The Brief Introduction Of Glass Fiber Extraction Thimbles

Classically, the glass fiber extraction thimbles without rubber are made of 100% alkali-free glass fiber and are produced at high temperatures. There is no adhesive, and it’s chemically inert. The glass fiber extraction thimbles are used to collect fine and submicron particles, which is an efficient and high-quality filtration device for catching pollution source particles, acid mist, aerosol, beryllium compounds, etc.

It has the advantages of high-temperature resistance, low weight loss, high capture efficiency, and high strength, and can be widely used in the sample collection of pollution source particles, metal compounds and so on.

For example, in the monitoring of air pollution, the monitoring of smoke emission concentration has become more conventional and mature. There are clear requirements for quality control and management specifications. In daily monitoring, the sampling collection is mainly by glass fiber extraction thimbles. The key to the success of the experiment is the stability of the weight of extraction thimbles when sampling atmospheric particles.

Appearance Inspection
No cracking is found in the base pressed after the glass fiber sleeve is added. Although the weld line is still visible on the part, there is no crack in the part. A simple test method is to apply the red or blue ink to the weld line of the shape of the part, to see if the ink is leaking out of the internal thread hole, and if the ink leaks out, it indicates that there is a crack there. The perfect shape is pursued in our production process.

Performance Inspection
According to the technical requirements, the high and low-temperature aging tests, vibration, impact and moisture resistance tests are carried out, and the mechanical and electrical properties of the parts meet the requirements of the technical conditions. No cracking was found in the tested base. The base parts are pressed by the above process method, and no cracking occurs after storage, assembly, and assembly of the whole machine, and the performance is good. The cracking of the base parts from the fusion line has been completely solved.

Property of Glass Fiber Extraction Thimble
Glass fiber extraction thimble is braided into a thimble with alkali-free glass fiber yarn, and then after high-temperature treatment, coated with silicone resin and silicone rubber.

Treatment Method of Glass Fiber Extraction Thimble
Folding injection molding will be adopted in the production of glass fiber extraction thimble, to begin with, the glass fiber thimble immersed in phenolic resin will be wrapped on the thread core in the injection die, close the die, and then press the injection molding on the 45t hydraulic press. The heating plate temperature is 180-200 ℃. Press pressure is 15~20MPa. The time of heat preservation and pressure preservation is 8 min and 10 min. Press the forming base according to the above process, glass fiber casing and parts become a whole.

The Brief Introduction Of Glass Fiber Extraction Thimbles

Cleaning, Disinfection And Pipetting Skills Of Bottle-Top Dispenser

The selection of the appropriate suction head has a great influence on the accuracy of the final dispenser, so it is best to select the suction head used in the initial calibration of the dispenser, that is, the suction head recommended by the manufacturer. In operation, when the lower end of the sleeve handle of the dispenser enters the suction head, the dispenser can be swayed from side to side for 1 to 2 seconds and gently pressed down; if it is a bulk suction head, gently pressing the suction head in the direction of the dispenser with hand, then turning the suction head slightly for 1 to 2 seconds.

Range Control of Bottle-top Dispenser
Generally speaking, the range of consumption of dispensers is 10 ≤ 100% of the maximum range of liquid shifters. For specific liquid shifters, the accuracy of the liquid shifters decreases with the decrease of the liquid shifters. In general, the best range is 30 ≤ 100% of the maximum range of liquid shifters. In the process of adjusting the range, the principle of from large to small are obeyed in order to eliminate the mechanical error of the liquid shifters themselves.

Internal and External Cleaning Method

Proper cleaning methods can maintain a bottle-top dispenser in good condition as long as possible. The following method should be followed strictly: using wet cloth containing soap. Detergent or 60% isopropanol cleaning solution, then removing external dirt from the dispenser, rinsing with double steamed water and drying; if the sample is polluted by mistake, the lower half of the dispenser needs to be removed and operated according to step 1.

Cleaning, Disinfection And Pipetting Skills Of Bottle-Top Dispenser

Steps For Operation Of Filter Paper

The specifications are important data for reference when using filter paper in the laboratory. Considering about the applicability, some filter paper is processed by special production procedures.

For example, when testing nitrogen content in blood in the application of medicine inspection, nitrogen-free filter paper must be used. When referring to capacity, because solid particles which are collected during the process of filtration will block the micropore on filter paper, the more intensive the micropore is, the higher the capacity the filter paper has.

On the other hand, there are two key specifications of filter paper. One is filtration features; another is physical properties. Specifically, filtration features include air permeability, airlock, the maximum diameter of micropore and average micropore size. Physical properties include fixing quantify, thickness, deflection, depth of the corrugated, bursting strength, resin content, and so on.

In detail, fix quantify refers to the mass per square meters of filter paper. Thickness refers to the thickness of filter paper excluding the depth of the corrugated. Airlock refers to the resistance of filter paper to the airflow. Air permeability refers to the air amount per unit time under certain areas and certain pressure. Deflection refers to the non-deformability of filter paper.

Specification
The specifications of Hawach filter paper for qualitative filter paper products can be found in the national standard (GB l 515). The aperture is about 80 μ 120 μ m, 30 μ m 50 μ m, and 1 μ 3 μ m, respectively. Hawach filter paper is committed to providing high filtration accuracy, which refers to the retention ability of filter paper to particles of a certain size, the size of a tiny sphere that can retain or filter out 50%, the resin content is usually from 10% to 30%, the depth of the grove to be pressed to enhance the stiffness of the filter paper in the longitudinal direction is usually 0-2 mm, and the maximum pressure that can be tolerated on the unit area of the filter paper is greatly enhanced by superior materials and delicate structure.

Steps for Operation
1. Fold the filter paper in the shape of the 90-degree round core. Then, divided into three layers on one side, and open the other side of the filter paper to form a funnel shape.
2. Put into the funnel, pour some clear water into the funnel mouth, contact the soaked filter paper with the inner wall of the funnel, and pour out the rest of the clear water.
3. Place the funnel with filter paper on the funnel frame for filtration, lower the beaker in the neck of the funnel, and keep the tip of the funnel on the wall of the receiving container.
5. When the liquid needing to be filtered is injected into the funnel, the right-hand holds the liquid beaker, the left-hand hold the glass rod, the lower end of the glass rod is close to the lower surface of the funnel, and the liquid cannot exceed the height of the filter paper in the funnel.
6. When the liquid passes through the filter paper and flows down the funnel neck, check if the liquid is running along the wall of the cup and pour it to the bottom of the cup.

Steps For Operation Of Filter Paper

Category Of Membrane Filter

MCE Membrane Filter
MCE membrane filter called mixed cellulose ester membrane filter, is ideal for colony counting and sterility testing. It is composed of cellulose acetate and cellulose nitrate, which has made it one of the best membranes in research and analytical applications. It is suitable for sterilizing filtration, air monitoring, and particle monitoring; it is also fit for clarification of aqueous removal and analysis and microbiology analysis.

Cellulose Acetate Membrane Filter
The protein absorption capacity of the cellulose acetate membrane is very low, which is very suitable for aqueous solution and alcohol. Cellulose acetate membrane has improved solvent resistance. The membrane filter can withstand 180℃ high temperature, so it is suitable for hot gas and disinfection by various methods while maintaining the integrity of the membrane.

Nylon Membrane Filter
Hawach Scientific are available in a broad range of pore size and materials such as Nylon. The nylon membrane filter is suitable for use with high PH samples and good for filtration of aqueous biological solutions, alcoholic solutions and other aqueous solutions where protein, peptide, and nucleic acid binding is not a concern. Nylon membrane filter contains no wetting agents, which can greatly reduce the potential for extractable and leachable and provide good chemical resistance with aggressive fluids.

Hawach Nylon membrane filter has good mechanical strength and strong adsorption, it can withstand most organic solvents and most alkaline solutions, especially fit for the filtration of alkaline and solutions. Hawach Nylon membrane is a supported, naturally hydrophilic membrane, which is designed to wet out evenly and retain its superior strength during use in general filtration.

Produced through a proprietary manufacturing process, Hawach Nylon membrane filter meets rigorous quality standards throughout every step of production. And this process generates consistent lot-to-lot binding among the membranes and ensures product uniformity. Low extractable guarantees tests will be clean and pure and lead to more stable results.

Category Of Membrane Filter

The Basics You Should Know About Syringe Filter

The syringe filter is a fast, convenient and reliable filter tool commonly used in laboratories. It is beautiful and light in appearance and high in cleanliness. It eliminates the need for membrane change and cleaning filters, with no need for complicated and time-consuming preparations.

It is widely used in the laboratory, for sample pre-filtration, clarification and sterilization filtration of particles, liquids, and air. It is the preferred method for filtering small samples of HPLC and GC and is often used in conjunction with disposable syringes. The filtration diameter is 4 mm to 50 mm, and the treatment amount is from 2 ml to 5000 ml.

The syringe filters provided by HAWACH can provide foundry services according to customer needs. The consistency of the produced batches of the filters is good. From the raw materials to the production process to the delivery management of the inbound and outbound warehouses, there are strict control processes to ensure to the greatest extent.

Material Introduction of Syringe Filter

1.PTFE Material
PTFE (polytetrafluoroethylene) is an effective filter for solvent chemicals and other non-aqueous solutions. A wide range of chemical compatibility, strong chemical stability, and inertia PTFE film is especially suitable for corrosive, strong acid, strong base chemical filtration can also be added ethanol and water to make it have certain hydrophobicity.

2.PVDF Material
PVDF (polyvinylidene fluoride) is suitable for highly corrosive organic solvents with hydrophilic properties and very low protein adsorption. It can filter out moisture in air and gas. PVDF film is coated on the support network, which has strong strength and maneuverability and can withstand high temperature.

3.PP Material
PP (polypropylene) takes food grade isotactic polypropylene as raw material, there are no additives in the whole production process; the physical and chemical properties are stable and have good compatibility; it has a series of pore size, high porosity, large amount of pollution, recoil and high temperature disinfection; good pressure resistance.

The Basics You Should Know About Syringe Filter

Do You Really Know The Differences Between The Glass Sample Vials?

The sample vials supplied by Hawach are precisely designed, engineered and manufactured to exacting specifications. Hawach also rigorously tests dimensions such as polishing, OD and length – to ensure that each vial is exactly matched to the autosampler jaw and sample system. The design and manufacture of caps and septa ensure a good seal and are compatible with other brands and other instruments.

Chromatographic performance tests on silicone rubber septa is performed to ensure the high purity requirements, impurity contamination elimination and possible analytical errors. The 2-40ml chromatographic injection bottles, headspace sample bottles and storage bottles are commonly used. Suitable for most autosamplers

Glass sample vials
Glass sample vials are the most common small consumables in the lab. But have you noticed that what materials made of the glass, what the differences between these materials are and how to distinguish between good and bad. Glass sample vials are generally made of borosilicate glass, with the commonly seen expansion coefficients of 3.3, 5.0 and 6.8. However, when the manufacturer sells the sample vial, there is almost no intended description of the material, so few people will care about what material it is.

Expansion coefficients
3.3: Mainly used in experimental instruments and household heat-resistant utensils; low expansion ratio, high-temperature resistance, high strength, high light transmittance, and high chemical stability; water resistance level 1.
5.0: Neutral glass, low expansion rate, high-temperature resistance, high strength, high chemical stability; water resistance level 1.
6.8: Low borosilicate glass, the chemical performance is worse than 3.3, but the cost is much lower than 3.3, it is suitable for one-time use.

Do You Really Know The Differences Between The Glass Sample Vials?

Some Tips About Reversed-Phase Flash Columns

Reliable and Reproducible
Hawach flash columns are precision-packed for high resolution as well as reproducibility. It features a one-piece design with Luer end fittings for easy connection to diverse chromatography systems. Hawach constantly pursues top technology to improve consumer feeling, for example, automatically detect the column type and size, and programs a default method, which can greatly reduce setup time and the potential errors in operation. A special chromatography technique uses compressed gas or a pump to make solvent pass flow through the column smoothly. As opposed to conventional gravity flow, Hawach flash column allows for faster flow rates and give special consideration for the stationary phase such as silica gel in the usage of finer particle size.

Versatile and Safe
Hawach flash columns are available in extra thick walls and cartridge pressure for safe operation. Flash column are all-welded end fittings ensure the column is able to withstand the pressure stability and not leak valuable compound. A wide offering of TLC plates makes operation easy, and delicate stationary phases expand the utility of the flash column. Moreover, high-quality media is specified for high resolution and reproducibility for high standard purification.

The selection of the mobile phase
The commonly used mobile phases are water with acetonitrile or water with methanol, occasionally water with tetrahydrofuran. Generally, we can add some weak acids or weak bases to adjust the liquid systems to partial acids or alkalis, which makes sure that the components can peak.

The commonly used weak acids are formic acid, trifluoroacetic acid. And the commonly used weak bases are ammonia water, ammonia bicarbonate, etc. The percentage added is generally the same as that in liquid systems.

A sampling of reversed-phase flash columns
In general, liquid phase wet sampling is used. Commonly used solvents include water, methanol, tetrahydrofuran, acetonitrile, NH-dimethylformamide, dimethyl sulfoxide.

Some Tips About Reversed-Phase Flash Columns

A Brief Introduction Of Hawach Filter Bag And Filter Capsule

With years of experience in the production line of lab consumables, Hawach is known for its outstanding performance in the industry, who constantly upgrade their products to meet the international standards. Hawach is able to provide on-time deliveries with high quality, thanks to a team of professionals and continuous hard work.

Hawach filter bag
The filter bag is made of porous short fiber non-woven fabric or nylon woven mesh by heat sealing or sewing. It has a deep filtering structure and good integrity. There are four kinds of materials at choice: polyester needle (PET), PP needle felt (PPF), PP flat sheet (PPP), nylon monofilament (NMO); and two kinds of interface materials: stainless steel ring, PP plastic ring. It features deep filtration, especially large filtration flow, low resistance, long service life, low cost, no fiber shedding, and easy operation.

Applications
Hawach filter bag has been widely used in the petrochemical industry; filtration of sugar, spices, juice, tea, etc. in the food industry; filtration and solvent filtration in polyester and acrylic production in the textile industry; recycling of valuable components in the pharmaceutical industry, gelatin, vitamins, syrup, etc.

Hawach capsule filter
The capsule filter is also called a disposable filter. The outer shell is made of high-temperature polypropylene material and the inner filter cartridge is hot-melted and welded together with the folding filter cartridge. It does not contain adhesives and other chemicals. The filter has different filter membranes and pore sizes, which can be autoclaved, suitable for filtering small dose liquids such as 1-20L laboratory, gas or industrial precious small volume liquid.

A Brief Introduction Of Hawach Filter Bag And Filter Capsule

Filtration And Membrane Filter

The filtration includes two methods: positive pressure and negative pressure filtration. The two kinds of methods can both make the solvent and the solute of smaller molecules pass through the filtration membrane with certain pore size, while the solute of larger molecules cannot pass through, so as to dehydrate, desalinate and concentrate the macromolecule materials, which will intercept the bacteria and parasites in order to achieve the purpose of sterilization, bacteria collection or increase the detection rate.

According to the size of separated substances, the membrane filtration technology is divided into microfiltration (MF), ultrafiltration (UF), reverse osmosis (RO) and nanofiltration (NF), etc.

Most of the filter membranes are made of high molecular materials, including cellulose ester, regenerated cellulose, polyamide, polyvinyl alcohol derivative, polyacrylonitrile, polypropylene, polyethylene, polyvinyl chloride, acrylonitrile/vinyl chloride copolymer, polycarbonate, polytetrafluoroethylene, polyvinylidene fluoride, etc.

The pore size of the membrane is expressed in μm, mainly including 0.025, 0.03, 0.05, 0.08, 0.1, 0.22, 0.3, 0.45, 0.6, 0.8, 1.0, 2.0, 3.0, 5.0, etc.

The main components of the membrane are including flat membrane, foldable membrane, tubular membrane, roll-type, and hollow fiber.

Cellulose Ester Materials is a standard membrane filter, characterized in good pore-forming performance, good hydrophobicity, easy availability of materials and low cost. And the pore size specification of the membrane is of a wide variety. The temperature range of the film is very wide. It is suitable for resistant to acid and base, but not suitable for ketone, ester, strong acid and alkali liquid filtration.

Filtration And Membrane Filter

To have a deeper understanding of HPLC column

Column structure: plastic protection head of the column; stud screw; blade ring; seal ring; filter (sieve plate); column (stainless steel tube) and column packing.

The sieve plate of the column is usually made of stainless steel or titanium alloy. Its pore diameter is generally between 0.2-20μm. The pore size depends mainly on the particle size of the column packing. It is a very important part and it can prevent the packing from leaking out. At the same time, it is to prevent the impurities from entering the column during operation to reduce the separation effect, and even the column is easily blocked.

The connection between the column and the infusion tube generally requires the use of a stainless steel ferrule and stainless steel fastening the joint screw. They are also very important, otherwise, the column system will leak, resulting in a drop in column pressure, a mobile phase or a sample leaking, which affects the analysis of test results, even the analysis, and testing work cannot be done.

HPLC column classification
In terms of type, the column can be divided into two types: preparative type and analytical type. Generally, the analytical type column is used most. If subdivided, the column can be further divided into a conventional column, a narrow column, a capillary column, a preparative column, and a semi-preparative column.

In order to improve the speed of analysis, short columns are often used, the column length is 5-10 cm, and the particle size of the filler is about 3 μm. Many analysts have emphasized analytical sensitivity, so narrow-diameter columns, capillary columns, and micro-diameter columns have been developed.

HPLC column efficiency
Column efficiency is the most important key indicator and generally depends on the performance of the stationary phase and the packing technology. There are roughly three types of column stationary phases (packings) for general HPLC: silica gel or silica-based fillers, polymer fillers, and inorganic fillers.

To have a deeper understanding of HPLC column

Do You Know Non-Sieve SPE Cartridges?

SPE is typically a sample preparation technique that uses chemical particles and chromatographic packing materials contained in a core-type device to chemically separate different components of a sample. Samples are almost always liquid, but special applications may use some of the samples in the gas phase. Figure 1 shows that a sample (shown in black) is being processed using an SPE device to separate each dye component that makes up the sample by chromatographic analysis.

A chromatographic bed can be used to separate different components in a sample, making subsequent analytical testing more successful. For example, SPE is commonly used to selectively remove interferents.

The exact name given to this technique from a technical point of view should be “liquid phase-solid phase extraction”; this is because the chromatographic particles are solid and the sample is in a liquid state. The basic chromatographic principle of liquid chromatography used here is the same as that of high-performance liquid chromatography, except that the form of use differs from the cause of use. Chromatography is used here to better prepare samples before they are submitted for analytical testing.

In terms of sample preparation, the source of the sample is very broad. They may be biological samples (eg plasma, saliva or urine), environmental samples (eg water, air or soil), foods (eg cereals, meat, and seafood), pharmaceuticals, nutritional supplement foods, beverages or industrial products. Even the head of a mosquito can be a sample! When scientists need to analyze neuropeptides extracted from the brains of mosquitoes, SPE is the preferred method of sample preparation

SPE (Solid Phase Extraction) solid-phase extraction is a popular pretreatment method for purifying liquid samples with solid adsorbents. Typically, SPE is used for purification, constant enrichment, desalination, derivatization, and separation prior to quantification by chromatography or other analytical methods.

What are the advantages of SPE compared to traditional LLE?
The effects of SPE and LLE (liquid-liquid extraction) are similar. LLE is an immiscible liquid two-phase extraction, while SPE extracts substances from the liquid phase to solid phase adsorption. The characteristics of SPE over LLE are:

Do You Know Non-Sieve SPE Cartridges?

The Introduction Of The Pipette Tips And Pipette Stand

Make sure that the pipette, the head, and the liquid are at the same temperature before liquid transferring at first. When sucking the liquid, you should hold the upper part of the pipette with four fingers together and press the button on the top of the plunger rod with your thumb. And then keep the pipette vertical, insert the head 2-3 mm below the liquid level. Release the button slowly, and stay for one or two seconds to suck liquid. Slide the head of the pipette out of the container along the wall. Finally, press the push rod of the head into the waste tank.

There are two methods of liquid transfer, as described below.

One is forward pipetting. Press the button with your thumb to the first stop spot, and then release the button back to the original spot slowly. Next, press the button to the first stop point to discharge the liquid, and then press the button to the second stop point to blow out the residual liquid. At last, release the button.

The other is reverse pipetting. Generally, the method is used to transfer liquid with high viscosity, biologically active, easily foaming. The principle is to suck liquid beyond the set range, and not blow out the residual liquid when transferring. First, press the button to the second stop point, and release the button to the original state slowly. Then press the button to the first stop point to discharge the liquid with the set range, and keep the button pressed and held at the first stop point. Remove the head with residual liquid and discard it.

Selection Knowledge of Pipette Tips

Significance of Selection
When choosing and purchasing pipettes, the users usually have taken a lot of factors such as precision, handle, brand, suction head adaptability and so on into consideration. In fact, the pipette tips will have a lot of impact on the accuracy of liquid transfer, because the tip bears the philosophy of perfect function, steady performance, and delicate appearance. Innovative handling and packaging of pipette tips are beneficial to overcome common problems of automatic pipette tips, such as static stacking and retention of residues.

The Introduction Of The Pipette Tips And Pipette Stand

The QuEChERS Method Facilitates Food Safety Detection

Let’s take a good look at the Quick, Easy, Cheap, Effective, Rugged, and Safe sample preparation technique: QuEChERS, the most efficient solid-phase extraction method for detecting pesticide residues in food. And Hawach QuEChERS products can make procedures easier than ever.

Packed with 50ml empty tube, Hawach QuEChERS extraction salts offer you a pre-weighed anhydrous extract salt. The anhydrous magnesium sulfate is to remove water from the sample matrix, and other buffer salts can provide a suitable pH to make sure that some alkali-sensitive pesticides have a good recovery rate.

When the sample comes with relatively high water content, the recovery rate might be influenced by the QuEChERS buffer salt reacting exothermically with water. Now you don’t need to worry about it because Hawach has separate extraction salt packs available, and you can add buffer salts after adding organic solvents.

You don’t need the specialized glassware when you use QuEChERS extraction salts as well. Free-flowing extraction salts and salt packets can perfectly fit into the extraction tubes and make transferring the salts to your sample neat and easy.

Food safety problem

Environmental pollution caused by unreasonable use of pesticides has caused widespread concern. So does food safety. With the enhancement of environmental awareness and the rapid development of the economy, the governments of various countries have paid more and more attention to the monitoring of pesticide residues in the environment and food. Strengthening research on pesticide residue detection technology has important theoretical and practical significance for the rational use of pesticides, environmental protection, and human health protection.

The QuEChERS Method Facilitates Food Safety Detection

About The Classification Of Vacuum Pump

Diaphragm vacuum pumps have the advantages of advanced design, wide work scope, and long service life. The pumps are mainly applied in the areas of medical product analysis, fine chemical engineering, biochemical pharmaceuticals, food detection, and public security criminal investigation technology. Furthermore, the diaphragm vacuum pumps are the products which support precision analytical instrument, and they are necessary equipment for laboratories.

Most of the diaphragm vacuum pumps can be operated without any working medium and do not produce any pollutants. At the same time, the gas exchange chambers of the pumps are equipped with filter materials so that a clean vacuum effect or positive pressure power will be guaranteed.

In general, diaphragm vacuum pumps always adopt new technology and new materials. They have compact and reasonable structures as well as small volume, low weight, and easy movement. In a word, the stable operation of diaphragm vacuum pumps can ensure the ideal vacuum effect or high flow capacity of the air current.

Moreover, diaphragm vacuum pumps adopt membrane movement without producing heat and frictional loss, which leads to long service life. Also, diaphragm vacuum pumps are equipped with a self-cooling exhaust system which can ensure 24 hours of continuous work.

Diaphragm vacuum pump, with advanced design, high work efficiency, and long service life, is a new generation of high-tech integrated products. Mainly used in medical and pharmaceutical product analysis, fine chemicals, biochemical pharmacy, food inspection, public security criminal investigation technology, etc. It is a product for its precision chromatography instruments and one of the necessary equipment for the laboratory.

Diaphragm vacuum pump design, high work efficiency, long service life, is a new generation of high-tech integrated products. It is mainly used in medical and pharmaceutical product analysis, fine chemical, biochemical pharmacy, food inspection, public security criminal investigation, and other fields. It is a product for its precision chromatography instruments and one of the necessary equipment for the laboratory.

About The Classification Of Vacuum Pump

How Many Steps Do You Need To Operate The Bottle-Top Dispenser?

Hawach bottle-top dispensers are liquid measuring devices, preventing spills to make our laboratory cleaner and safer. The bottle-top dispensers can attach to the top of the bottles which contain the liquid to be measured, and make allow safe and accurate liquid distribution without contamination. Hawach bottle-top dispenser has a wide field of applications in biology, clinical, chemical, pharmaceutical, and forensic labs.

The air purging system on the bottle-top dispensers helps to avoid the loss of expensive reagents and media messes during liquid transfers. The nozzle can dispenses liquids accurately into the receiving container easily. The right-angled spout of bottle-top dispensers does not require any cap to keep clean workspaces in your lab. You can find that Hawach bottle top dispensing system is so innovative that it fits lots of laboratory chemicals including corrosive and flammable liquids and its most standard laboratory bottles.

To match your needs, Hawach bottle-top dispensers include mechanical bottle-top dispensers and electronic bottle-top dispensers.both of them are safe and convenient with the volume regulation which makes your liquid distribution quickly and accurately. And the electronic control system on electronic bottle-top dispensers makes the process more stable and reliable.

Preparation before operation
Before use, please check whether the bottle-top dispenser damage or not. If there is a malfunction (such as difficulty in plunger movement or valve blockage), the liquid separation operation should be stopped immediately. Before use, please clean it according to the cleaning instructions or contact the manufacturer. Pls, note the bottle-top dispenser is made of polypropylene (PP) and can only be used to dispense liquids that do not react with PP materials.

Operation steps
Step 1 Connect the outlet tube
Do not use a non-standard dispensing tube; do not use a damaged or deformed outlet tube.
1. Tighten the liquid outlet valve with a tool
2. Insert the outlet tube as deep as possible into the outlet valve

Step 2 Connect the inlet tube
1. Tilt cut the inlet tube
2. Insert the inlet tube into the inlet valve as deep as possible so that the beveled side is at the bottom.

How Many Steps Do You Need To Operate The Bottle-Top Dispenser?

Which Kind Of Filter Paper Is Suitable For You?

Filter paper is frequently used in lab experiments. Filter paper loose and has a strong absorption ability to liquid. The filter paper commonly seen in the analytical laboratory is used as a filter medium to separate the solution from the solid.

The right filter paper will get twofold results with half the effort. Choosing the right filter paper can be determined by considering the following four factors. At present, the filter papers mainly include quantitative analysis filter paper, qualitative analysis filter paper and chromatographic qualitative analysis filter paper.

Hawach Scientific co., LTD. is specializing in the production of Qualitative filter paper, product quality stability, exported to all parts of the world.

Qualitative filter paper refers to “qualitative analysis filter paper”, which is compared with quantitative analysis filter paper and chromatography qualitative analysis filter paper. The paper is loose and has a strong absorption of liquid.

Qualitative analysis filter paper generally has a large amount of residual ash, which is only used for general qualitative analysis and filtration of precipitation or suspended substances in solution, not for quality analysis.

(1) the general use of natural filtration, the use of filter paper and the ability to trap solid particles, so that the liquid and solid separation;
(2) as a result of the filter paper mechanical strength and toughness are weak, as far as possible with less filtering method, such as must accelerate the filtering speed, in order to prevent filtering failure, in the air pump filtering, according to the size of the suction in the funnel stack 2 ~ 3 layers of filter paper, in the vacuum filtering, in the leakage.First pad a layer of dense press cloth, and then put filter paper to filter;
(3) filter paper had better not filter hot concentrated sulfuric acid or nitric acid solution.

Consideration In Selection Of Syringe Filter

When syringe filter is used to treat chromatographic samples, it is necessary to avoid the introduction of other impurities in the filtration process. The appearance of this impurity may be that the shell material or filter membrane will drop particles and bring it into the filtrate. Therefore, the material of filter membrane and shell structure is very important. Different types of filter membranes are suitable for samples with different properties.

1) Hydrophilic samples: hydrophilic membranes are selected, which have affinity to water and are suitable for filtering water as matrix solution. The available filter membranes are mixed cellulose ester, polyethersulfone (PES) Nylon and so on. 
2) Strong corrosion erosion organic solvents (properties: transparent, colorless liquid): hydrophobic membranes, such as PTF E, polypropylene (PP) and other material quality filter membranes, are generally used. 
3) Protein solution: select low protein adsorption filter membrane, such as PVDF filter membrane.┬а 4) Ion chromatography: it is generally considered that the PES filter membrane is more suitable for filtration of a solution of a low inorganic ion.

Sample Volume

In addition to the above factors, the volume of the sample shall be taken into account, and when the sample volume is less than 2 ml, a micro-filter with a diameter of 4 mm is selected; the sample quantity is between 2 and 10 ml, and a filter with a diameter of 13 mm is used; when the sample quantity is more than 10 ml, a needle type filter with a diameter of 25 mm is used.

Tolerance of syringe filter

Syringe filter provided by Hawach Scientific uses PTFE as source materials, which is an effective filter for solvent chemicals and other non-aqueous solutions. The chemical stability and the inert PTFE membrane with strong chemical compatibility are particularly suitable for filtration of the corrosive, strong acid and strong alkali chemical, and the ethanol and the water can be added so as to have certain hydrophobicity.┬аMoreover, the product structure design is precise, the inner space rationalization, the residual rate is very low, and thus it ensures the filtration fluency and reduces the sample waste.

Consideration In Selection Of Syringe Filter

Ways Of Cleaning Sample Vials

As the rapid development of analytical chemistry, more and more large analytical instruments are applied in all areas of detection, especially in gas chromatography, liquid chromatography and mass spectrum. These instruments need large amounts of sample vials to be matched with. If the sample vials are only for single use, that would be great waste and huge cost. Generally, laboratory workers often clean the sample vials for reusing.

However, during the cleaning, as the bottle mouths are very small, the air inside the sample vials cannot be eliminated smoothly and the cleaning solvent cannot flow into the sample vials, which lead to poor effect in the end.

In China, there are a great number of agricultural products that need to be tested every year, using Liquid Chromatogram or Gas Chromatogram. Cleaning sample vials are of great importance, which is related to the test results. Clean the sample vials according to the glassware cleaning instructions and degree of contamination, and you can choose different cleaning methods.

As a result, laboratory workers have developed some batch cleaning methods which are with the advantages of handiness, low cost and high efficiency.

For example, we can put the sample vials into the reagent bottle firstly, then add the organic solvent to the mouth of the reagent bottle, cover with hole less plug and screw the outer cover. Secondly, we can use the vortex mixer to eliminate the air inside the sample vials, then fill in the reagent bottle with organic solvent over time. Thirdly, we put the reagent bottle into the supersonic cleaner with the cleaning temperature between 30 ℃ to 50 ℃ to clean for 1 minute to 15 minutes. Lastly, we eliminate the organic solvent from the reagent bottle.

Ways Of Cleaning Sample Vials

Polymeric MAX, MCX, And HLB SPE Cartridges

Polymeric MAX SPE cartridges are used to the extraction of acidic compounds. MAX is a mixed strong anion exchange adsorbent obtained by bonding quaternary ammonium to highly crosslinked PS/DVB surface. It has strong anion exchange and reverse phase retention, and is suitable for the extraction of acidic compounds.

Polymeric MAX SPE cartridges can be wetting and are not easy to penetrate, whose PH tolerance range is wide. They are stable acid compound extraction cartridges in the organic solvent.

Polymeric MCX SPE cartridges are used to overcome the limitations of traditional silica matrix mixed solid-phase extraction adsorbent. It is a mixed type of strong cation exchange, water – wettable polymer adsorbent and has high selectivity and sensitivity to basic compounds.
Polymeric MCX SPE cartridges provide dual retention modes: ion exchange and inversion, and retention occur on a clean, stable, high-surface-area, a stable organic copolymer with a pH range of 0 to 14.

Polymeric MCX SPE cartridges require a high adsorption capacity to effectively extract alkaline compounds from biological substrates using a mixed solid-phase extraction absorbent.

The curved-type silica matrix mixed adsorbent of polymeric MCX SPE cartridges is synthesized through a complex process that is difficult to control and has a relatively low exchange capacity (within the range of 0.06-0.2meqlg).

Polymeric HLB SPE cartridges are used to extract nonpolar to the medium polarity of acidic, neutral and alkaline compounds. HLB hydrophilic and lipophilic equilibrium packing is prepared by special copolymerization technology and contain a specific proportion of hydrophilic and hydrophobic groups.

Polymeric HLB SPE cartridges can recycle nonpolar to the medium polarity of acidic, neutral and alkaline compounds and are especially suitable for complex matrices, such as blood, urine and food processing.

Advantages of polymeric MAX SPE cartridges
1. Easy operation, good reproducibility;
2. Save the cost of instruments and consumables;
3. No blank background interference;
4. High recovery rate;
5. High specific surface area and large exchange capacity;
6. Stable quality.

Advantages of polymeric HLB SPE cartridges
1. Universal packing, wide application range;
2. High water infiltration, not afraid of solvent drainage, not easy to penetrate;
3. High recovery and good reproducibility;
4. Tolerable to PH 1 – 14, compatible with most solvents;
5. Adsorption capacity and sample load were much higher than C18 bonded silica gel.

Polymeric MAX, MCX, And HLB SPE Cartridges

About The Development Of Flash Column

In 1978, Still invented flash chromatography, published in J.O.C, from which the flash method was established. Flash column is derived from open glass column chromatography and is mainly used for the separation and purification of natural products and organic synthesis products. The classical flash chromatogram consists of a glass column, a liquid storage bottle, and a compressed air regulating valve. With low cost, it is easy to observe, but the pressure is low and easy to break.

Many laboratories now place a pressurized ball on top of a glass column, which is a similar product and forms a classic flash chromatography system after improved. It consists of the infusion pressure tank, flows regulating valve, flashes pre-packing column and sample loading device. The equipment is compact, easy to use, with high pressure and high reproducibility. The classic flash chromatogram is still pressurized with air pressure, the pressure range is about 0-7 bar, the column length is about 15 cm, and the filler particle size is 40-60 Torr. The solid and liquid can be loaded and the fraction collected by hand.

Development
Over 20 years of development, the flash column has been widely used as a conventional purification separation device. The narrowly defined flash column refers to a low-pressure short-column preparative liquid chromatography system that uses compressed gas to generate pressure and accelerate the elution rate of the mobile phase. The generalized flash column system refers to the medium-low pressure liquid chromatography system of all infusion methods.

Recently, because of the intensification of scientific research competition and the increase of laboratory labor costs, higher automation and separation speed are required, resulting in automated flash columns, chromatography pumps, detectors, automatic fraction collectors and workstations. Some also have a gradient elution system, a column switching system, and an automatic sample introduction system. The conditions can be optimized to achieve unmanned operation, which greatly reduces labor costs and speeds up development.

About The Development Of Flash Column

Liquid Filter Housings

Hawach filter housing is an equipment that is commonly used to filtrate or purify samples in pharmaceutical, electronics, chemical, and other fields. Due to an optimized construction, Hawach’s filter housing offers low differential pressures at high flow rates and compatible with high pressure or high-temperature applications.

A multitude of various housings with different connections makes it suitable for high standard filtration. Smooth and round corner design greatly eliminates dead angles and media shedding. All Hawach’s filter housings conform to the requirements of international standards for simple pressure vessels.

Highlights of Filter Housing
Hawach Scientific always makes an endeavor to produce high-quality, cost-effective filter housing, and make great achievement in less adsorption, high filtration accuracy, and excellent corrosion resistance. It is of extremely robust construction and high mechanical strength, which is ideal for strong acid and alkali.

Complete stainless steel structure and polished inner wall design provide convenient maintenance and long service time. It is the perfect choice for cost-sensitive applications that need a reliable analysis result and good sealing capabilities. And Hawach almost available all kinds of filter housings, contact us for detailed information.

Hawach is home to five kinds of filter housings to meet different requirements.

1. Stainless steel liquid filter housing BJH:
It is internally ground and polished, no dead angle, low flow resistance, acid and alkali resistance, easy to clean; can be equipped with different filter cartridges according to requirements, in line with food and pharmaceutical GMP requirements, which is the ideal filtration equipment for the food and pharmaceutical industry;

Liquid Filter Housings

Membrane Filtration Technology

Membrane filtration technology is, actually a kind of membrane separation technology, which driving force relies on the pressure. And this technology includes MF, UF, NF, and RO. When the solution flows over the membrane, under certain pressure, only water or some small molecule is allowed to get through the numerous micropores distributing over the membrane and turned into permeate.

Other matters whose volume is greater than the diameter of membrane micropores would be stopped and turned into a concentrated solution. According to this principle, the membrane filter realizes solution separation and concentration. It is a kind of advanced water treatment technology.

The installing of the membrane component
Make sure the system has been cleaned before you install the membrane components. Before you install the reverse osmosis membrane into the system, the O ring and the seal need to be lubricated. You can use a 50% glycerin-water solution. Oil, grease, vaseline or other petroleum compound are prohibited.

Micro-filtration Membrane
The micro-filtration membrane is a kind of precise filtration and can be divided into dead-end and crossflow. The former is usually used in small-scale applications and the filter elements are always one-off. The latter is usually used in industry huge scale and it requires periodic cleaning and regeneration to recover the filtering performance of the membrane.

Micro-filtration membrane mainly used in the pharmaceutical industry degerming filtration. Besides, it is also widely used in urban sewage disposal and wastewater treatment preprocessing.

Ultrafiltration Membrane
Ultrafiltration membrane is a kind of membrane process which is between nanofiltration and microfiltration. It applies to the separation, concentration, and purification of macromolecular substance and small molecular substance.

The early industry ultrafiltration only applied to the treatment of sewage and wastewater. In the latest decades, with the development of ultrafiltration technology, it has been used in the food and drinks processing, medicine industry, clinical medicine, and sewage treatment, etc.

Membrane Filtration Technology

FAQ Analysis And Solutions About HPLC Columns

FAQ analysis and solutions about HPLC columns

1.The column pressure is too high, after a period of use.
Solution: First check whether the HPLC system is the cause. After eliminating the system cause, the reason is basically due to the accumulation of impurities in the column during the experiment. Try to improve the operating conditions. After the sample is finished, it should be rinsed off in time. For example, the mobile phase of the buffer salt must be washed with a high proportion of aqueous solution (such as 90%) and then stored with the organic phase.

2.Sieve plate blockage and column head collapse.
Solution: If it is determined that the filter screen of the column head is contaminated, the column can be flushed to normal pressure in the opposite direction with methanol, or the column head should be removed, the sieve plate should be carefully removed, and the solution should be sonicated for about 20 minutes with a 5% or so nitric acid solution. Then, it is sonicated with pure water for about 20 minutes and reloaded into the column.

3.The packing of the column head is contaminated by the sample.
Solution: If it is determined that the packing of the column head is contaminated, remove the stud screws, dig out the contaminated packing in the front part of the column, refill with the same column packing. And after careful repair, reinstall the stud screws.

4.The salt in the buffer in the column encounters a high concentration of methanol or other organic solvent to form crystals and precipitate.
Solution: If it is determined to be salt crystals, rinse the column with 10% methanol/water to dissolve all the salt in the column, and then change the high concentration of methanol.

Notes
1. Whenever possible, the column bed must be kept dry, especially during the injection test and column flushing process, the mobile phase should not be left empty for more than 30 minutes. Otherwise, the column will dry up and can be discharged into a large amount of non-ejectable bubbles which even cause partial collapse or central cracking of the bed.
2. For use and storage, it is strictly forbidden to use force to absolutely prevent accidental violent impact or falling at high places. Otherwise, it will easily cause mechanical damage to the column bed, then there will be no regeneration.
3. When the column and the chromatograph are coupled, the valve or pipe must be cleaned.

FAQ Analysis And Solutions About HPLC Columns

Pipette Operation And Common Mistakes

Pipette is a perfect tool to transport a measured volume of liquid. It is widely used as a media dispenser in labs. For different purposes and needs of accuracy and precision, we can find pipettes in several designs in the market, glass and polyethylene ones. Adjustable and electronic pipettes are available too.

The pipette is always needed wherever the precise transfer of liquid is required in the lab. Regardless of what type the pipette you have, you should handle them with care. Placing the pipette 1/4 of an inch from the bottom of the container is the right way to prevent damage when you draw the liquid. You’d better tap the side of the pipette to remove excess droplets very gently when the required volume of the liquid is drawn up. Always hold the pipette at a 10-20 degree angle when you dispense. Never blow through a pipette and try to remove extra liquid.

To make sure the pipettes working accurately and also to prevent pollution from previous contents, you should clean the them after use.

Operation Procedures of Pipette
To do a correct liquid operation using a normal pipette, there are some operating steps for follow, first, connect the suction head, then press the piston exhaust, insert the suction head approximately 2 mm below the liquid level, next, inhale liquid and transfer to the destination container, finally, push off the suction head. It takes about 10 seconds for the whole process.

Maintenance Procedures of Pipette
In experimental operation, when there is liquid in the suction nozzle of the pipette, do not place the it horizontally or inversely to prevent the liquid flowing into the piston chamber to corrode the pipette piston.

Besides, use the pipette correctly to absorb and drain liquid to achieve high precision; when it occurs leakage in operation, stop for one to three seconds after suction to see whether the liquid level in the suction head drops, if the liquid level drop, firstly to check whether there is a problem with the suction head, if it is, just replace the suction head, if not, call for professional maintenance personnel to repair.

Pipette Operation And Common Mistakes

Two Major Hawach Products Used In QuEChERS Method

If you are looking for a Quick, Easy, Cheap, Effective, Rugged, and Safe sample preparation technique, let’s start with QuEChERS. Developed and published by US scientists in 2003, QuEChERS was originally designed for the analysis of fruits and vegetables. Now, it can take practice on lots of agricultural products, such as animal products, milk, honey, food products, cereals, and grain products.

What is QuEChERS?
It is a pretreatment method in pesticide residue detection, which has the characteristics of Quick、Easy、Cheap、Effective、Rugged、Safe; it is the standard method for pesticide residue detection recognized by developed countries, say the AOAC 2007.01 (analysis of national standards for pesticide residues in the United States) Method, and EN 15662 (European legal standard analytical method).

Extraction and purification kit
The Hawach kit is designed to make the QuEChERS method faster, including QuEChERS extraction kits and purification kits. The extraction kit includes a salt pack and a 50ml centrifuge tube. For laboratories that prepare their own tubes, Hawach also provides bulk salts and adsorbents. The purification kit is directly adsorbed in a centrifuge tube, including 2ml and 15ml two specifications.

Suitability
Hawash’s kits are suitable for: common fruits and vegetables, fruits and vegetables containing fats and waxes, and colored fruits and vegetables. Its products are manufactured under strict IS0-9001 standards and include a wide selection of polymers, silica gels and other adsorbents ranging from small columns of various sizes to orifice plates. Hawach also offers a full line of multi-tube vacuum systems and accessories.

Two Major Hawach Products Used In QuEChERS Method

Two Major Hawach Products Used In QuEChERS Method

If you are looking for a Quick, Easy, Cheap, Effective, Rugged, and Safe sample preparation technique, let’s start with QuEChERS. Developed and published by US scientists in 2003, QuEChERS was originally designed for the analysis of fruits and vegetables. Now, it can take practice on lots of agricultural products, such as animal products, milk, honey, food products, cereals, and grain products.

What is QuEChERS?
It is a pretreatment method in pesticide residue detection, which has the characteristics of Quick、Easy、Cheap、Effective、Rugged、Safe; it is the standard method for pesticide residue detection recognized by developed countries, say the AOAC 2007.01 (analysis of national standards for pesticide residues in the United States) Method, and EN 15662 (European legal standard analytical method).

Extraction and purification kit
The Hawach kit is designed to make the QuEChERS method faster, including QuEChERS extraction kits and purification kits. The extraction kit includes a salt pack and a 50ml centrifuge tube. For laboratories that prepare their own tubes, Hawach also provides bulk salts and adsorbents. The purification kit is directly adsorbed in a centrifuge tube, including 2ml and 15ml two specifications.

Suitability
Hawash’s kits are suitable for: common fruits and vegetables, fruits and vegetables containing fats and waxes, and colored fruits and vegetables. Its products are manufactured under strict IS0-9001 standards and include a wide selection of polymers, silica gels and other adsorbents ranging from small columns of various sizes to orifice plates. Hawach also offers a full line of multi-tube vacuum systems and accessories.

Two Major Hawach Products Used In QuEChERS Method