Hawach Syringe Filter Classification

From the raw materials to the production process to the delivery management of the warehouse, there is a strict control process.

HAWACH guarantees the quality and use value of the products to the greatest extent. HAWACH filters are available in a variety of sizes and membrane options for easy use in sterile and non-sterile laboratory applications.

Whether your research requires pre-filtration, sample preparation, sterile filtration, laboratory filtration, or venting, the HAWACH syringe filter is a must-have for your laboratory.

HAWACH syringe filter classification

The following are mainly divided into three series according to HAWACH positioning:

1. Filstar series

This series belongs to high-end models, with transparent color and imported membrane. It can be divided into different kinds based on different focuses. There are pre-filter ones and also some have not. It can also be sterilized and non-sterile. Form the aspect of membrane materials, there are active carbon, nylon, PTFE, PTFE L, PES, PVDF, MCE, CA, GF and PP.

2. Winstar series

This series belongs to low-end models, with colored ring and domestic membrane. It can be only non-sterile and also there fewer choice for the membrane materials, nylon, PTFE, PTFE L, PES and PVDF.

3. Sterile series

This series belongs to high-end models, with transparent color, Millipore equivalent membrane, and fewest choice, nylon, PTFE B, PTFE L and PVDF.

Hawach Syringe Filter Classification

Five Methods To Clean Sample Vials

In China, a large number of agricultural product samples, other chemical products, organic acids, etc. will be detected by gas or liquid chromatography. Cleaning of the sample vial is very important. The cleaning method is selected based on the degree of contamination and there is no fixed mode.

Option 1
1. Drain the test solution in the sample vial.
2. Dip all into the 95% alcohol, dry it after twice ultrasonic washing, as the alcohol easily enters the 1.5mL vial and can be mutually soluble with most organic solvents.
3. Pour into clean water and ultrasonic washing 2 times.
4. Drain the bottle and bake at 110 ℃ for 1~2 hours. It should not be baked at high temperature.
5. Cool and save.

Option 2
1. Wash it with the tap water several times.
2. Place in a beaker with pure water, sonicate for 15 minutes.
3. Change the water, then sonicate for 15 minutes.
4. Soak in a beaker with absolute ethanol.
5. Finally, take out ans dry with natural air.

Solution 3
1. Soak with a yeast (chromatographically pure) and ultrasonically clean for 20 minutes, then pour out the yeast.
2. Fill the injection bottle with water, ultrasonically clean for 20 minutes, then pour out the water.
3. Dry the sample vial.

Option 4:
1. Generally, it is first rinsed with water and then soaked with potassium dichromate wash solution.
2. The washing method of the injection bottle is the same as the other ones. First, use medical alcohol to infuse for more than 4 hours, then ultrasonic for half an hour, then pour out the medical alcohol, use water ultrasonic for half an hour, rinse with water and dry it.

Option 5:
1. If there is enough budget, it is best to use news ones.
2. If it is to be reused, the cleaning method is also very important. First, soak it with a strong oxidizing cleaning solution (potassium chlorate) for 24 hours, then wash it with deionized water for three times under ultrasonic conditions, and finally wash it with methanol once and dry.
3. The bottle mat must be replaced with new, especially when analyzing pesticide residues, otherwise, it will affect the quantitative results.

Five Methods To Clean Sample Vials

Flash Chromatography And Flash Columns

Invented by Professor Clark Still of Columbia University several years ago, flash chromatography was popularized nowadays. To replace the slow and inefficient gravity-fed chromatography, flash chromatography works differently from the old ways.

Slightly smaller silica gel particles are used, and the pressurized gas is used to drive the solvent through the column of stationary phase because the restricted solvent flow is caused by the small gel particles in practice. Due to this two innovation, we can get a high efficient resolution chromatography.

You can always find Hawach flash columns with special high purity stationary phased packed with the full range of sizes. With the cartridge made from medical grade virgin PP material and PE frits.

From hydrophilic to hydrophobic, Hawach offers excellent separation performance flash columns for compounds analysis of a varies of properties. And the stationary phase includes Standard Silica gel, Superior Silica gel, Spherical C18, Irregular C18, Spherical NH2, Spherical C4, Spherical C8, Spherical CN, Spherical HILIC, Neutral Alumina, Spherical Phenyl, Spherical SAX, Spherical SCX, Spherical C8, Spherical Diol, etc..

Flash Chromatography And Flash Columns

Overall Instruction of Filter Membrane

In order to use the filter membrane properly and efficiently, there are several certain aspects as below that need to be paid attention to by the users.

Operation Instruction

The number one rule of membrane selection is that remember to select the filter membrane recommended in the experimental instructions. The first necessary step before the filtration is to conduct the cleaning procedure.

The filter membrane shall be cleaned with distilled water and then be soaked in the distilled water with the temperature kept between 70-80 degrees for four hours (or 12 hours in the normal temperature distilled water). the next step would be sterilization for those membranes that are not sterilized before going into the market.

The most common method is to put the cleaned filter into the filter first, and then go through the autoclaving process in 120 degrees for half an hour. In case that the sterilization process causes the membrane to be dry, just soak it with sterile water before use, otherwise, it will have an influence on the filtration efficiency.

Transportation and Storage

The filter membrane is supposed to be stored in the place that is not subjected to direct sunbeam, and its ambient temperature should be under a normal condition with the 60% relative humidity. The cellulose filter membrane is flammable, which must be kept away from fire during transportation as well as storage.

Overall Instruction of Filter Membrane

About The Maintenance Of The Pipette

Placement
After use, you can hang it vertically on the pipette holder, and make sure it will not fall off. When there is liquid in the pipette tip, do not place the pipette horizontally or upside down to prevent the liquid from flowing back to corrode the piston spring.

Maintenance
If not used, adjust the range of the pipette to the maximum value to keep the spring in a relaxed state to protect the spring. It is best to clean the pipette regularly, either with soapy water or 60% isopropanol, then with distilled water, and air dry. Before autoclaving, make sure the pipette is suitable for high temperatures.

Calibration can be carried out by repeating the weighing of distilled water several times in a 20-25 degree environment.

Check for leaks before use. If there is liquid leakage, the reasons are as follows:
1. Whether the tip matches
2. Whether the spring piston normal
3. If it is a volatile liquid (as is the case with many organic solvents), it may be a problem of saturated vapor pressure. You can suck up the liquid several times before pipetting.

About The Maintenance Of The Pipette

Brief Introduction On QuEChERS

QuEChERS is a kind of rapid sample pretreatment technology, which is often used for agricultural products detection in recent years. QuEChERS provided by Hawach Scientific is noted for high recovery and accuracy, fast speed analysis, low contamination, and convenient operation.

And it adopts a highly beneficial analytical approach to simplify the analysis of multiple pesticide residues in fruit, vegetables, and processed products, etc. The QuEChERS entails a number of simple analytical steps and gives full flexibility in the choice of the determinative analysis technique.

Features of QuEChERS

QuEChERS developed by Hawach is compact designed which makes the structure of the product’s tightly packed, cleverly made, operate more simple. Besides, it also realizes the homogenization, oscillation, mixing and integration of the samples, and liberates customers from heavy repetitive work and greatly reduce sample preprocessing time.

QuEChERS marketed by Hawach has comprehensive types of products, full sale, and after-sale service for product and solution, and great recovery for a wide range of pesticides in food matrices. Other obvious features are that the QuEChERS has the great capabilities of grinding the sample, and simple procedure with few steps to lower potential for errors.

Brief Introduction On QuEChERS

Introduction And Performance Of Filter Cartridge

Filter cartridge provided by Hawach Scientific is considered as an excellent alternative to conventional filter bag as its improved performance and design, and it is widely used for the filtration of various impurities in different fields, such as fields in foods, pharmaceuticals, chemicals, and electronics.

It is highly appreciated for its high-temperature resistance, high dust holding capacity and chemical abrasion proof design. And it is well known for its easy installation, these filter cartridges need no tool due to their safety lock from the clean side. Specially designed for used in a variety of impurities filtration applications, it is suitable for high dirt loads.

Performance of Filter Cartridge

Filter cartridge supplied by Hawach Scientific has the characteristics of excellent chemical compatibility, superior quality, high flow rate, low-pressure difference, low price, and wide filtration precision. Large filter area and depth filtration provide a long lifetime of the filter cartridge.

The filter medium in cartridges is easy to adjust depending on the nature of the application. We offer this cartridge to clients in a wide selection of lengths and filter areas for meeting different needs.

Introduction And Performance Of Filter Cartridge

Vacuum Filtration In Practice

Filtration is the process in which solid particles in a liquid or gaseous fluid are removed by permitting the fluid to go through and retain the solid particles with a filter medium. According to the different nature of the driving force, there are gravity filters, pressure filters, and vacuum filters.

In the applications of collecting particulate from a liquid suspension, vacuum filtration is driven by negative pressure applied downstream of the filter holder in the lab. The retentate on the filter’s surface or the fluid filtrate is available for more analysis.

Vacuum filtration is widely applied in the laboratory for various analysis such as microorganism test in food, pharmacy, beverage, drinking water industries and suspended solid test in the water treatment field, solvent (mobile phase)refinement before HPLC, GC, AA analysis, etc.

Our collection of vacuum filtration equipment, such as diaphragm vacuum pumps, glass vacuum filtrations and stainless steel vacuum filtrations, provide high quality components for all of your lab’s vacuum filtration processes.

Vacuum Filtration In Practice

The Introduction To Soxhlet Extraction

Soxhlet extraction is a common method for solid and liquid extraction. It is mainly applied for the extraction and separation of solid samples.

The Soxhlet extraction uses the principle of backflow and siphon of the solvent, and make continuous extraction of the needed components in the solid mixture. When the liquid level of solvent which backflows in the extraction shell surpass the siphon of the Soxhlet extractor, the solvent will flow back to the round-bottom flask, and then the siphon happens.

As the temperature goes up, the backflow starts again. Before each time of the siphon, the solid matter can be extracted by the pure hot solvent and the extracted substances will be concentrated in the flask. At the same time, the solvent can be recycled. It reduces the extraction time and improves extraction efficiency.

In comparison with other common solvent extraction methods, the Soxhlet extraction saves time and solvent, and also improve the extraction efficiency. However, it is not suitable for the extraction of the hot and labile element.

The separation effect and concentration factor are related to the character of the sample, the extraction temperature, the extraction time and the character and dosage of solvent. In general, the sample should be concentrated in the organic solvent as far as possible.

The Introduction To Soxhlet Extraction

Installation And Maintenance of Bottle-Top Dispenser

Installation of Bottle-top Dispenser

Bottle-top dispenser provided by Hawach Scientific can meet the needs of a wide range of applications, especially for the direct removal of corrosive reagents from reagent bottles. To provide better customer experience, the device is of easy installation. The components are very few, the key part of the valve is formed in one body, so the assembly is very easy.

Only need to choose appropriate closure caps, adapters, and bottles, then screw those parts on right place according to relative instructions. After installation, it is better to check whether the device is in good condition, or not, screw each part tightly and operate again.

Maintenance of Bottle-top dispenser

Hawach Scientific bottle-top dispenser can be sterilized at high temperature and high pressure. The convenient design ensures the simple and economical cleaning and maintenance of the liquid dispense. Good material and few components greatly save maintenance times. In most cases, there is no need for maintenance or replacement.
Any non-human breakdown occurs during normal use, Hawach promises to provide free replacement and maintenance services for three months. Contact us for more details.

Installation And Maintenance of Bottle-Top Dispenser

How To Choose The Right Filter Papers?

As a mechanical-physical operation, the scientists in the lab use filtering paper to separate solids from fluids. solids in the fluid which are bigger than the pole of the filter media, can stay on and within the surface of the filter media, by interposing a porous media through which only the fluid can pass.

You can find filter papers in a variety of different options available around. It is very important that you choose the right type for your filtration. In other words, the success of filtration in the lab depends on your choice of filter paper, with the consideration of combing two important features: retention and flow rate.

Hawach provides filter papers in the range of qualitative and quantitative types to meet all of your particular needs for your application. And all of Hawach filter paper is made from pure cotton linters with The ash content mainly less than 0.006%.

We guarantee that all the Hawach filter paper are always produced under strict controlled manufacturing conditions to assure the stable high quality.

How To Choose The Right Filter Papers?

knowledge Of Glass Solvent Filter

Glass solvent filter is made of high-quality extra hard glass, which makes it become sparkling and crystal-clear. Its size meets the international standard size. Its voltage resistance and leakage proof are very good. Additionally, it is suitable for filtration at high temperature and high pressure.

Types of Glass Solvent Filter

Glass Solvent Filter includes two types, one is 300ml glass solvent filter, and the other is 500ml glass solvent filter. Those two types are of some similarity in following aspects, for example, the branch is single, the funnel valve is glass, the support screen is Pyrex glass, the connection is ground joint, and screen pore size is 10μm.

Besides, both of them can work under 121℃ high temperature. The difference is in funnel size and collection bottle: the 300ml glass solvent filter is smaller than the 500ml glass solvent filter in those aspects.

Maintenance of Glass Solvent Filter

The glass solvent filter should be work under safe and suitable environment and be kept in a correct way, concretely, strictly following the operating instructions, or its performance could be affected. In case damage occurs, it is better to furnish information about the operation of the device and related descriptive materials.

knowledge Of Glass Solvent Filter

The Tips of Flash Column

Flash column chromatography is a fast and easy way to separate complex mixtures of compounds for the scientists in the lab. compressed air is used to push the solvent through the column when we running the flash columns. The process not only provides better separation but cuts down the running time too.

Even though flash column chromatography is not a new concept, but it is still the primary technique for purification in the lab, as it is fast, easy and convenient. The same physical principles which work on HPLC also apply flash chromatography with the ability to use either normal-phase or reverse-phase and using bonded phases to modify elution profiles. Due to these characteristics, flash chromatography can be used in the field of natural products purification.

Hawach always provides high purity stationary phased packed flash column in the full range of size for our costumers, with the column cartridge made from medical grade virgin PP material and PE frits, and the standard Luer-lock end fittings which can connect to most of the flash system easily.

The Tips of Flash Column

Materials Of Filter Cartridge

The filter cartridge is a device for purification and separation. Nowadays, it is mainly used in filtration industry, such as oil filtration, air filtration, and water filtration, filtering impurity and separating substance. Liquid filter cartridge makes polluted liquid, including oil and water, clean to an extent. While the air filter cartridge purifies the air.

Materials of filter cartridge:

There are many kinds of filter cartridge made of different materials, paper cartridge, chemical fiber filter, screen filter. They are put in a filtering device to separate material components. According to its making materials, it can be divided into the metal filter, air filter, an activated carbon filter element.

How to tell:
The filtering material in an air filter cartridge is filter paper, which has good filtering quality. Filter paper of bad quality cannot stop the dust getting into the engine, and it would affect the work of the engine. Generally speaking, a filter cartridge of good quality has filter paper of single color and smooth surface. Besides, the filter cartridge can recover very soon after folding.

Materials Of Filter Cartridge

The Classification Of Membrane Filter

Membranes filters are classified according to the size of particles retained in raw water. Membrane holes are divided into microfiltration membranes (MF), ultrafiltration membranes (UF), nanofiltration membranes (NF) and reverse osmosis membranes (RO). The pore size of the MF membrane is more than 0.05um, or its molecular weight is more than 1000. The removal of colloids and macromolecule organic compounds is the object of the MF membrane.

The pore size of NF membranes ranges from 100 to 1000 molecular weight. It removes substances between UF and RO to remove trihalomethane, odor, chroma, pesticides, soluble organic matter, Ca, Mg and so on. The particle size of RO is 10 moles, and the removal of salt and inorganic salt is the object of RO separation.

The pressure of RO seepage water is 1-2 times higher than that of RO seepage water. In addition to the above four, there are ion exchange membranes and gas permeation membranes. MF, UF, NF, and RO are driven by the pressure to separate solids from the liquid. Ion exchange membranes are driven by electricity to separate salt molecules and promote desalination of seawater. Gas permeation membrane is a new type of membrane which can concentrate ethanol and desalinate seawater through the gas.

The Classification Of Membrane Filter

The Basic Knowledge Of HPLC Column

HPLC column is a separate analysis technology developed in the late 1960s and is an important means of modern separation and determination. It is widely used in biochemistry, drug, and clinical analysis because of its high separation efficiency, fast analysis speed, good detection sensitivity, and ability to analyze high-boiling but not vaporizable thermo-labile physiologically active substances.

Component

The system of high-performance liquid chromatography (HPLC) column consists of a reservoir, a pump, an injector, a column, a detector, a recorder, and the like.

Working principle

The high-pressure pump drives the mobile phase in the reservoir into the system and the sample solution enters the mobile phase via the sample injector and is flowed to the stationary phase.

Since the components in the sample solution have different partition coefficients in the two phases, each component produces a large difference in moving speed, after repeated multiple adsorption-desorption processes, during the relative motion in the two phases.

Thus they are separated into individual components and sequentially flowed out of the column. When passing through the detector, the sample concentration is converted into an electrical signal and transmitted to the recorder, and the data is printed in the form of a graph.

The Basic Knowledge Of HPLC Column

Operation And Difference Of SPE Cartridge

Operation of SPE Cartridge

In order to achieve greater reproducibility and cleaner samples, enhance performance consistency, reduce extraction time and avoid sample contamination, there are some operational suggestions or tips for customers to follow, specifically as follows: firstly, making sure it in a cleaning state before operation, next, choosing and putting appropriate samples in cartridge, conditioning for a while, and then carrying out sample load and washing, finally, performing sample elusion. When the whole process is finished, cleaning and drying the SPE cartridge immediately, and place it in holding the box.

The difference between SPE Cartridge

Since SPE Cartridge provided by Hawach Scientific is available in different types, and each type has its own special features, we made an endeavor to provide comprehensive instructions on our products.

Reversed-Phase is more suitable for use in the biological macromolecules sample and used to extract lipid soluble and water vitamins at the same time from other compounds; Ion-Exchange is often applied to separation of basic compounds from particle aqueous and keep permanent negative charge in the range of pH; Mixed Mode is fit for purification of alkaline aqueous solution or neutral compounds in urine and blood, such as drugs and metabolites.

Operation And Difference Of SPE Cartridge

The Classification Of HPLC Column

The frequently used HPLC columns are packed with silica, which is divided into normal phase columns and reversed-phase columns. Other packing columns are also available in polymer fillers and inorganic fillers.

1.Normal phase

The stationary phase for normal phase chromatography is typically silica gel and other bonded phase fillers with polar functional groups. As the silicon hydroxy group (SiOH) or other polar groups on the surface of the silica gel are relatively polar, the order of separation is based on the polarity of each component in the sample, that is, the component with weak polarity is first washed out.

2.Reverse phase

The packing for the reverse phase column is usually based on silica gel with a bonded phase bonded to a relatively weakly polar functional group. The mobile phase used in reverse phase HPLC column is more polar, which is usually a mixture of water, buffer and methanol, acetonitrile, and the like.

The order in which the sample exits the column is that the more polar component is first washed out, while the less polar component is more retained on the column. Commonly used reverse packing materials are C18 (ODS), C8 (MOS), C4 (Butyl), C6H5 (Phenyl) and the like.

The Classification Of HPLC Column

Sample Vial Cleaning Method

As an important instrument in the laboratory, the cleaning of sample vial is particularly critical. The specific methods are as follows:

Program I
1. In-bottle test solution of reverse-drying chromatographic sample.
2. Immerse in 95% alcohol, wash it twice with ultrasound and dry it, because alcohol is easy to enter 1.5mL bottle and can dissolve with most organic solvents.
3. Pour in clear water and wash twice with ultrasound.
4. Pour the lotion in the drying bottle and bake at 110 degrees Celsius for 1-2 hours. Be careful not to bake at high temperature.
5. Cooling and preserving.

Program II
1. Soak in methanol (chromatographic purity) for 20 minutes, then dry the methanol.
2. Fill the chromatographic sample vials with water, wash it with ultrasound for 20 minutes, and then dry it.
3. After that, the chromatographic sample vials were dried.

Program III
1. Rinse the tap water several times.
2. Put it in a beaker filled with pure water and ultrasonic for 15 minutes.
3. Change the water and ultrasound for 15 minutes.
4. Soak in a beaker filled with anhydrous ethanol.
5. Then take out the natural air drying.

Sample Vial Cleaning Method

Diversity of Syringe Filter

Currently, syringe filter is designed for sterilizing and clarifying, and suitable for both medical and laboratory applications. Syringe filter offered by Hawach Scientific is manufactured in a controlled environment with an automated process, which ensures the quality and use value of the product to the maximum extent.

Besides, precisely designed structure ensures the fluency of the filtration. Reasonable inner space minimize the hold-up volume, so that the waste is minimized. Housing material is medical grade polypropylene, which makes it provides with excellent compatibility with organic solvents and strong acids and bases.

Diversity of Syringe Filter

Syringe filter provided by Hawach Scientific mainly falls into three types: disposable syringe filter, syringe filter, and sterile syringe filter. All of them are suitable for use with a wide range of applications from filtering of biological samples to clarify aggressive solvents, strong acids, alcohols, based and aromatics.

Additionally, all of them are characterized in precision structure, smooth filtration, reasonable inside space, and low residue rate. In practical application, all of them could bear high temperature, and will not have leakage at all.

Diversity of Syringe Filter

The Advantages of Liquid Filter Bag

The liquid filter bag is one of the most important parts of the filter, and it is also the key element during the filtration process. The liquid filter bag is also called the heart of the filter because it decides the filtration effect to a great extent.

On a whole, except multiple material choices, a complete range of specifications and can be used repeatedly, the liquid filter bag has many other advantages which can meet the requirements pointedly in every field.

Firstly, the filter bag is manufactured by high-speed industrial sewing machine which adopts cooling of silicone oil-free, so that there will not produce any silicone oil pollution.

Secondly, the seams of liquid filter bags are flat and with no needle eyes, which means the situation of side leakage will not happen.

Thirdly, the labels which specify the specifications and models on the liquid filter bags are all easy to be removed, so we can prevent the labels and printing ink from polluting the filtrate during the use.

Moreover, the filter fineness of the liquid filter bags with the materials of polyester, polypropylene, and nylon, are ranging from 0.5 micrometers to 300 micrometers.

The Advantages of Liquid Filter Bag

Selection And Advantage Of HPLC Columns

Selection of HPLC Columns
Hawach HPLC columns are available with the full range of types and sizes such as standard series C18, Amino Acid, HILIC Amide, CN, C30, Diol, C8/C18 Low pH and Reversed-Phase series and so on.

All these columns are endowed with high column efficiency, low pressure and good corrosion tolerance for longer service time. Some suggestions on the selection of columns are as follows,C18 Alkaline HPLC Columns are fir for separation of alkaloids ingredients from Chinese medicine, C1 HPLC Columns are suitable for separation of proteins samples and hydrophobic polypeptide in reverse phase, Amino Acid HPLC Columns can apply to applications like Bio-pharmaceutical, Proteins, Cell Culture Media, and Feeds and so on.

Advantage of HPLC Columns
HPLC columns manufactured by Hawach Scientific are of some obvious advantages in retention, peak shape, and pressure. Through advanced technology and unique design, Hawach overcomes many pressure problems which are due to blockage in the system or guard, such as plugged packing, plugged frit, and column contamination.

Besides, many peak shape issue caused by column void, partially plugged frit or injection solvent effects are solved, and retention issues such as selectivity changes or retention time changes are also resolved. If you have any questions regarding column quality, or if there are signs of damage, contact us immediately.

Selection And Advantage Of HPLC Columns

Several Problems Affecting the Flow Rate of the SPE Cartridges

The basic operation of SPE cartridges includes five steps: activation, balance, sampling, wash, and elution. Generally speaking, those matters affecting the velocity of the SPE cartridges arise in these steps. Here we especially talk about the process of activation and balance. In that process, people fill the fillers at first.

In general, reversed-phase or ion-exchange columns are activated and balanced by methanol and water respectively, while normal-phase columns are activated by petroleum ether or n-hexane.

First, filling too tight results in slow flow rate. People can solve these matters through increasing the flow rate under pressure or purchasing products from manufacturers with strict quality control of convection rate.

Second, when the size of the fillers is smaller, the flow rate will be slower. People need to select the proper size of columns according to the type of sample matrix and the usage habit.

The third is the difference in the pipe volume. Obviously, the large diameter and the low height of the fillers means the fast flow rate. The selection of the columns with suitable pipe volume is also based on the type of sample matrix and the usage habit.

Several Problems Affecting the Flow Rate of the SPE Cartridges

Operation And Accessories On Vacuum Filtration

Operation of vacuum filtration

Vacuum filtration designed by Hawach does not need to use traditional buffer bottles and other accessories, thus customers can operate more simple and easy to use. All the firmware and spare parts required for each filter are concentrated in one body, and the space occupied is greatly reduced. Magnet at the bottom of the filter bottle can be firmly adsorbed on the machine to avoid toppling and shaking.

All stainless steel shell is strong and durable, easy to wipe and clean. Besides, the filter gasket adopts stainless steel making process, and the gasket watch is smooth to ensure the high smoothness of the filter film at the end of filtration, which is beneficial to the subsequent drying and weighing operation.

Accessories of vacuum filtration

Other accessories such as diaphragm vacuum pumps and glass solvent filters are also available in Hawach. The pump body is made of all-PTFE hard materials and has a strong resistance to acid and alkali chemical corrosion.

The user does not have to worry about the corrosion and damage of internal parts for a long time. With vacuum gauge and control valve, vacuum and filter speed can be adjusted according to the actual needs.

Operation And Accessories On Vacuum Filtration

FAQ of SPE Cartridge

There is no doubt that there are lots of various problems shown in the use of the SPE cartridge. In particular, several typical problems would be analyzed below, which could be greatly useful for operators and future customers.

Low Recovery Rate

Usually, two main reasons will cause the result of a low recovery rate.

The first one is that the sample remains insufficient on the filler – the actual detection concentration of the sample solution and the eluent exceeds 5%. no matter the excessive elution strength of the solution, the dry cartridge or high volume of the sample solution would all cause the insufficient sample.

The second reason is that the sample is not completely eluted. Either improving the eluting strength or the eluent volume would solve this problem.

Poor Reproducibility

The following situations could trigger the occurrence of poor reproducibility, including the poor matrix removal effect, sample blockage phenomenon, the fast flow rate, and human operation error. To change the pre-processing method is a clever move to better reproducibility.
Poor purification effect.

A permanent way to improve the purification effect is definitely to choose the most suitable SPE cartridge. Besides, operators could also change the pretreatment method used or eluent strength. To conduct the proper SPE operation is also necessary.

FAQ of SPE Cartridge

Brief Introduction Of Hawach Pipettes Products

Fixed and adjustable volume pipettes are widely used to transport a small measured volume of liquid in the lab, often used as a media dispenser. You can find Hawach products from single and multi-channel pipettes to more complex adjustable pipettes. Designs for various purposes with differing levels of accuracy and precision, Hawach provides electronic and mechanical pipettes.

The right pipette tip is key for proceeding the accurate and reliable results. Divided into advanced pipette tips, standard pipettes, and advanced filter pipette tips, Hawach pipette tips are designed for multiple applications. With volume ranges from 10ul to 10ml, Hawach pipette tips are flexible and soft tip cone that ensures better sealing without leaking. And you can always get the best recovery of the sample liquid.

Hawach has two different kinds of pipettes stand, linear stand and round stand. Both of them can hold up 6 pipettes. The stand can keep the pipettes away from contamination after use. It also can help you to make your lab neat and in the right order.

Brief Introduction Of Hawach Pipettes Products

Prospect Of QuEChERS Method In Pesticide Residue Analysis

Due to the wide application of chemical pesticides in food production and storage, and the increasing import and export trade, relevant management agencies will use a variety of different analytical methods to monitor food safety quality.

QuEChERS method can meet the requirements of the management department due to its unique procedures, as well as its advantages of quickness, convenience, easy operation, high sensitivity, and low cost. It will become the preferred pretreatment method for routine detection of pesticide residues in small laboratories around the world.

Development

After the QuEChERS method was introduced, the laboratory was effectively evaluated and verified by several laboratories including the US FDA. Some laboratories have applied the method to routine pesticide monitoring. Agilent Technologies Ltd. also validated this method in 2008 and promoted it in China. It is now working with the Ministry of Agriculture to plan the QuEChERS method as a standard in China.

Prospect

With the development and widespread application of pesticide residue detection technologies such as LC_MS, GC_MS, GC_MSn, and LC_MSn, the QuEChERS pesticide residue pretreatment method is not only widely used in sample pretreatment of agricultural pesticide multi-residue detection and It will also be widely used in the fields of pesticide residue detection, agricultural veterinary drug testing, and biological sample drug testing.

Prospect Of QuEChERS Method In Pesticide Residue Analysis

Matters Need Attention On Glass Fiber Extraction Thimbles

Hawach glass fiber extraction thimble is elaborately processed by special technology and made of high-grade special superfine glass fiber. It is an efficient filter device that is used to collect harmful substances such as smoke, acid fog, and beryllium substitutes. It has advantages, such as high-temperature resistance, low weight loss, high efficiency, and good strength.

People should pay attention to the following points when using because of the characteristics of glass fibers.

First, check the sampling heads to ensure the taper is matching and the clearance is appropriate.

Second, make sure it is not affected by tearing force, shearing force or some other forces in case that the mouth is not broken when loading or unloading the extraction thimbles.

Third, people should use the extraction thimbles in the appropriate temperature range which means they are under sufficient strength. It is reported that the strength of glass fibers begins to decrease when they are heated to more than 200 C and then cooled.

The glass fiber extraction thimble is promoted to widely use since put into production since 1974, which prompts the smoke and dust detection in China.

Matters Need Attention On Glass Fiber Extraction Thimbles

Matters Need Attention On Bottle-Top Dispenser

Bottle-top dispenser supplied by Hawach has good quality and attractive appearance, and there are some attentions to prolong the service life of it. It is necessary to ensure that the inlet valve and drain pipe, as well as all valves, are properly installed and tightly screwed to avoid spatter of piston movement.

Please stop immediately when a failure occurs in drainage, do not operate violently, so as not to further damage the instrument. Besides, once you finished all the operation, please buckle the helmet of the drain pipe to prevent the liquid in the outlet from dripping due to gravity or absorbing water vapor from the air.

Performance of Bottle-Top Dispenser

Hawach is committed to developing a series of bottle-top dispensers featured with concise structure, reliable and durable performance. The dispenser adopts PEEK materials, which provides perfect high-temperature resistance, strong corrosion tolerance, good self-lubricity, and mechanical properties.

Special process technology greatly improved mechanical properties and shock resistance. The electronic control system is beneficial for stable batching process and reduction of repeated strain damage.

Matters Need Attention On Bottle-Top Dispenser

About Qualitative And Quantitative Filter Paper

Filter paper is a kind of paper with good filtering quality, which is usually used in an assay laboratory to separate solutions and solid and do qualitative chemical analysis.

Qualitative analysis filter paper usually used in some non-numerical calculations qualitative test of chloride and sulfate. While quantitative analysis filter paper are used in filtering which needs precision numerical calculations.

About quantitative analysis filter paper:

In the process of producing quantitative analysis filter paper, pulp processed by hydrochloric acid and hydrofluoric acid is washed with distilled water, which remove impurities from the paper fiber. There is little residual ash content after burning, and almost no influence in analysis results. Two kinds of filter paper in shape can be chosen, including circle and square with more specifications.

About qualitative analysis filter paper:

Qualitative analysis filter paper can not be used in quality analysis. It can only be used in filtering, precipitation and general qualitative analysis.

About Qualitative And Quantitative Filter Paper

The Working Principle of Membrane Filter

Compared with traditional processes, UF membrane technology has the advantages of low energy consumption, low operating pressure, high separation efficiency, high flux, and recoverable useful substances. It is widely used in drinking water purification, domestic sewage recovery, oily wastewater, pulp wastewater, seawater desalination, and other water treatment. Next, the working principle of the ultrafiltration membrane filter is introduced.

Ultrafiltration (UF) membranes filter is solutions under pressure. Solvents and some low molecular weight solutes pass through the micropore on the membrane to the other side of the membrane, while macromolecule solutes or other emulsified micelles are intercepted to achieve separation from the solution.

The mechanism of interception is mainly screening, but sometimes the chemical properties of the membrane surface (electrostatic action of the membrane) also play an interception role. Ultrafiltration separation is a process in which macromolecule and colloidal substances are blocked in the pore due to the primary adsorption of the membrane filter surface and micropore, and the mechanical screening of membrane surface is blocked by ultrafiltration membrane, while water, inorganic salts, and low molecular substances pass through the membrane.

Ultrafiltration membrane technology has a defining range of molecular weight rejection of about 500-500000, the corresponding pore size of about 0.002-0.1 um.

The Working Principle of Membrane Filter

Sample Preparation Technology – Solid Phase Extraction

Solid phase extraction (SPE) is the use of a solid adsorbent to adsorb a target compound in a liquid sample, which is separated from the matrix of the sample and the interfering compound. Then, it is eluted with an eluent or desorbed by heating to achieve the purpose of separating and enriching the target compound.

Compared with liquid-liquid extraction, solid-phase extraction has many advantages: solid phase extraction does not require a large amount of solvent, which does not cause emulsification during the treatment.

It uses a highly efficient and highly selective adsorbent (stationary phase). Significantly reduces solvent usage and simplifies sample pretreatment while reducing costs. In general, solid-phase extraction costs one-fifth of the liquid-liquid extraction, but the disadvantage is that the recovery and precision of the target compound are slightly lower than the liquid-liquid extraction.

Solid phase extraction is essentially the first liquid chromatographic separation. It can be divided into normal phase (the polarity of the adsorbent is greater than the polarity of the eluent), and the reverse phase (the polarity of the adsorbent is less than Eluent polarity), ion exchange and adsorption.

The adsorbent used in solid phase extraction is the same as the stationary phase commonly used in liquid chromatography, except that it differs in particle size.

Sample Preparation Technology – Solid Phase Extraction