Filter Paper For Quantitative And Qualitative Analysis

The filtration products are widely used in the field of solvent filtering, cellulose analysis and lots of industrial applications as well。 Knowing as an essential tool for the labs and industrial process which involves separation and purification，filter paper plays an important role in the processes of separating and purifying in different stages of chromatography.

Besides being a purification product, filter paper usually comes out with muti-functions. Different types of filter papers can offer different filtration levels and capacities. You can find that they are also made for specific samples in particular applications. Application of the filtration product in the right industrial and research needs can be highly beneficial to the overall process.

Filter Paper for Quantitative Analysis
Hawach Scientific are available of high-grade filter papers which are indispensable for routine work in industrial applications and laboratory. Hawach offers a full range of 100+ individual grades of filter and technical papers all manufactured to your exacting standards and engineered to solve all filtration challenges. Quantitative filter papers are provided with complete sizes such as grade BIO-40, BIO-41, BIO-42, BIO-43 and BIO 44. All of them are manufactured to meet ISO 9001 and ISO 14001 environmental management standards. Moreover, Hawach is committed to offer ash-free filters with a variety of thicknesses, with flow rates and characteristics from wide pore and fast to narrow pore, as well as slow rates.

Filter Paper for Qualitative Analysis
Qualitative filter papers provided by Hawach are made of 100% cotton linters, multiple diameters, thickness, filtration rates and different grades such as BIO-1, BIO-2, BIO-4, BIO-6, BIO-91, AND BIO-113 can greatly satisfy nearly every need. Furthermore, it can be applied to general absorption and blotting, chromatography or even protection of the surface. Proven product consistency and customized design are fit for your exact requirements.

The Notice of Using Filter Paper
According to the size of the pore, the filter paper can be divided into fast-speed, medium-speed, and low-speed types. In terms of the size of the diameter, there are types of 7 cm, 9 cm, and 11 cm. When we choose which type of filter paper to use in the laboratory, we should consider the quality of precipitate.

Specifically, the low-speed filter paper is suitable for filtration of the fine-crystal precipitate; the medium-speed is for coarse-crystal precipitate, and the fast-speed is for gelatinous precipitate. When referring to the size of the filter paper, it should be based on the quantity of precipitate. Normally, the height of the precipitate is not allowed to surpass 1/3 of the height of the filter paper cone. Moreover, the size of the filter paper should match the size of the funnel. In general, the upper edge of the filter paper should be 1 cm lower than the upper edge of the funnel. Speaking to the funnel, it should be with the long neck of 15 cm to 20 cm, and the angle of the funnel cone should be 60°. Furthermore, in order to keep the liquid column in the neck, the diameter of the long neck should be 3 mm to 5 mm.

Filter Paper For Quantitative And Qualitative Analysis

Material Source And Classification Of Syringe Filter

Syringe filter manufactured by Hawach Scientific commonly adopts cellulose acetate membrane, polyethersulfone membrane, or glass fiber cellulose acetate membrane as filter material, which has good hydrophilicity and strong chemical compatibility. Moreover, syringe filter made from above materials are suitable for sterilization filtration of hydrophilic solution and liquid medium, and pre-filtration, clarification and sterilization filtration of refractory aqueous solution.

Common syringe filter and pre-filtered syringe filter

The common syringe filter adopts single layer microporous filter membrane, which can be used to filter general samples and is economical and applicable. Pre-filtered syringe filter uses pre-filter membrane to filter the coarse particle impurities in the air. In the process of production, transportation and use, it can protect the main filter material, prevent the main filter membrane damage and aging, improve the service life of the product, and enhance the filtration flow as well as filtration effect. When the needle filter comes out of the chromatographic sample, it is necessary to avoid the introduction of other impurities in the filtration process.

The F & H filter head can be used for pre clarification, particle removal, bacteria removal and filtration of mobile phase and sample in chromatographic analysis. It is also widely used in weight analysis, microanalysis, colloid separation and sterility test.

Product series, characteristics and application: (specification: Ф 25mm, Ф 13mm).

1. Syringe filter of water system (PES, PES)

2. Syringe filter of water system water system (MEC, mixed cellulose ester)

Characteristics: uniform pore size, high porosity, no medium shedding, thin texture, small resistance, fast filtration speed, little adsorption. Main use: filter out bacteria, gas, oil, beverage, wine and other particles and bacteria, which can be used for particle and bacteria inspection.

3. Syringe filter of water system organic system (nylon)

Characteristics: hydrophilic, no need to wet in advance. The pore size is uniform and has strong flexibility and adsorption, which can ensure the effective retention capacity to meet the application requirements of fine filtration. The chemical compatibility is good, it can be compatible with most reagents, without fiber shedding, and it completely conforms to the pharmaceutical industry standards. Typical applications: electronic, microelectronic, semiconductor, industrial water filtration, high-purity chemical filtration, pharmaceutical liquid filtration, beverage filtration.

4. Syringe filter of water system organic system (PVDF)

Features: good heat resistance and chemical stability, complete coverage on both sides of the membrane, no fiber exposure, dense surface pore distribution, consistent pore size on the front and back sides, hydrophobic hesitation, can be used for various corrosive liquid sterilization, particle removal filtration, gas steam dehumidification, dust removal and bacteria removal filtration. Main application: ideal material for separation of downstream products of food industry, medical industry and bioengineering.

5. Syringe filter of water system organic system (polytetrafluoroethylene PTFE)

Features: chemical stability and inertness, suitable for strong corrosive organic solvents, strong acid and strong alkali solutions. Main uses: organic solvent sterilization and filtration, gas purification sterilization and filtration.

Material Source And Classification Of Syringe Filter

What Kinds Of Lab Experimental Consumables Can HAWACH Provide?

HAWACH is specialized in manufacturing various kinds of lad products to meet your experiment requirement. With many years of professional experience in the lab field and 100,000 clean workshop and ISO9001 certificate, HAWACH aims to provide high-quality products with the best service and best price to its customers.

Main products
Its main business covers bottle-top dispenser, pipette, QuEChERS related products, flash column, HPLC column, SPE cartridge, syringe filter, filter cartridge (including, filter bag, filter capsule, filter housing), membrane filter, extraction thimble, filter paper, and vacuum filtration. HAWACH products are the ones used in the QuEChERS method, including the extraction box (salt bag and 50ml centrifuge tube) and the purification box. SPE cartridge is usually used in laboratory small sample pretreatment, with 1ml, 3ml, 6ml and 12ml at choice.

1. Extraction thimble
HAWACH mainly produces cellulose extraction thimbles, used in general Soxhlet extraction and glass fiber extraction thimbles, used when cellulose cartridges cannot be tried, like with a temperature higher than 120℃, strong acids, etc.

Generally, in a glass container below, it places the substance to be extracted, and the solution is repeatedly immersed to extract the required components from the substance (such as extracting pesticide residues from pepper). This experimental process is called Soxhlet extract. The extraction thimble also plays an important role in collecting particulate matter such as haze in the atmosphere. It is used with the haze collection device.

2. Syringe filter
In HPLC analysis, the chromatographic column packing has a small particle size and is easily clogged with foreign particles, so samples and solvents need to be filtered in advance to remove particulate contaminants and protect the instrument. The ion chromatography commonly used in the environmental analysis also requires that no inorganic pollutants be introduced into the sample pretreatment. We usually use it in HPLC analysis and IC analysis. Filtering the sample solution is an important step in the sample pretreatment process. The filter is available in the material of Nylon, MCE, CA, CN, PES, PVDF, PTFE, PP, Glass Fiber, with pore size ranging from 0.1μm to 10μm, which had been widely used in such industries as pharmacy, chemistry, bioscience, microelectronics, food & beverage, etc.

3. Vacuum filtration
HAWACH vacuum filtration device can replace the circulating water vacuum pumps and rotary vane vacuum pumps. It requires no special working medium, without friction in the working part. The vacuum index can be adjusted according to experimental requirements. All parts in contact with the gas are made of rubber material, which has a strong resistance to chemical corrosion. The valve disc is made of high-quality materials, with branded motors. The transmission mechanism has a reasonable design, reliable operation, small size, lightweight, convenient movement, and space-saving.

4. QuEChERS products
HAWACH products are the things used in the QuEChERS method, including extraction boxes and purification boxes. Extraction box includes salt pack and 50ml centrifuge tube. The purification box is filled with the adsorbent directly in a 2ml, 15ml centrifuge tube. Another type of product is a set, that is, an extraction box + a purification box, by which the customer can do the whole set of experiments.

In addition to the above products, Hawach also supplies pipette, bottle-top dispenser, filter paper, membrane, SPE/FLASH/HPLC columns and so on. Welcome to visit www.hawach.com to learn more.

What Kinds Of Lab Experimental Consumables Can HAWACH Provide?

Background And Rational Of Vacuum Filtration

The vacuum filtration is a device that realizes solid-separation with vacuum negative pressure as the driving force. In terms of the structure, the filtration section is arranged along the horizontal length direction, which can continuously complete filtration, washing, drying and other operations. It is mainly used for solid-liquid separation, liquid clarification, sterilizing, removing impurities and also for room temperature reaction.

Background and Rational of vacuum filtration
Traditionally, the separation is usually carried out by a conical funnel with a filter paper of different sizes, through which the liquid is pushed through the filter membrane by natural penetration and gravity. However there exist a great disadvantages. The pore size of the filter membrane will cause great resistance to the liquid, resulting in an extremely slow filtration speed.

Compared with traditional separation method, vacuum filtration can help greatly improve the filtration efficiency and save time.
Main performance of vacuum filtration:

1. Filtration bottle is made of borosilicate glass with excellent chemical and physical properties.
2. It has stainless steel brinell funnel, with excellent physical and chemical properties.
3. Stirring plug is made of special PTFE material, with perfect technology, corrosion resistance, and high cost performance.
4. There is no blind corner in the container, which is detachable for solid material discharge.
5. The machine is completely sealed, and the negative pressure can reach below 0.095 mpa at rest.

Advantages of HAWACH Vacuum Filtration
The core highlights of HAWACH vacuum filtration device can be represented from the following aspects:
Pump:
1. Advanced design, high work efficiency, and long service life.
2. It can work without any medium(oil-free pump), without pollution. Meanwhile, the air exchange chamber of the machine is built with filtering materials, so as to ensure the purity of the air.
3. Ideal vacuum degree and high air velocity
4. The motor is provided by ODM, a professional export motor manufacturer
5. It is equipped with a hot power protector: when the temperature of the pump reaches 130℃, the power will cut off automatically to protect the motor from loss.
6. Adopt friction-less membrane body movement, o heat and no friction loss. Adopt imported rubber for diaphragm, corrosion resistance and long service life.
7. The machine is designed with automatic cooling and exhausting system to ensure 24-hour continuous operation.
8. There is a surface treatment by Teflon for the connected parts of the anti-corrosion pump and gas, which has a complete resistance to chemical corrosion.

Stainless Steel Multi-connection Vacuum Filter:
1. It can process multiple samples at the same time with no pollution and can improve working efficiency.
2. Stainless steel filter can be easily used for high temperature disinfection, with high temperature resistance, and corrosion resistance.

Solvent filter:
1. With high quality glass materials, which is smooth and transparent, with no bubble.
2. The glass material is used to resist the temperature variation up to 280℃.
3. It has goof pressure resistance and can be used for high temperature and high pressure sterilization
4. With fast flow, standard grinding and good sealing performance.
5. The size and specification are in line with international standards, which can match with various foreign brands.

Background And Rational Of Vacuum Filtration

Cellulose Extraction Thimble Use In Soxhlet Extractor

The extraction thimble is made of high-quality cellulose long fiber or cotton wool fiber, which is made with a highly homogenized mold. Soxhlet extraction is a widely used technique for the analysis of lipids and other solid-liquid extraction in food and soil materials – often used for the analysis of fats and pesticide residues in food and soil samples, or for the determination of crude oil in cement slurries. Oil content (different from 1PS phase separation paper for determination of oil content in oilfield wastewater)

Extraction thimble use in Soxhlet extractor:

The Soxhlet extractor is composed of an extraction bottle, an extraction tube, and a condenser. There are siphon tubes and connecting tubes on the two sides of the extraction tube, and the connection of each part must be tight to prevent air leakage. During extraction, the sample to be tested is placed in a cellulose filter cartridge and placed in an extraction thimble. Petroleum ether is added to the extraction bottle, the extraction bottle is heated, the petroleum ether is vaporized, rises from the connecting pipe into the condenser, and condenses into a liquid and drips into the extraction pipe to extract the lipids in the sample.

When the level of petroleum ether in the extraction tube reaches a certain level, the petroleum ether in which crude fat is dissolved flows into the extraction thimble bottle through a siphon. The petroleum ether flowing into the extraction bottle continues to be heated, gasified, raised and condensed, and then dripped into the extraction thimble, and so on until the extraction is complete.

Soxhlet extractor main features:
1. When operating the Soxhlet extractor, the heating temperature can be adjusted according to the boiling point of the reagent and the ambient temperature;
2. The sample is repeatedly immersed and extracted during the extraction process to achieve the purpose of rapid extraction;
3. The solvent can be automatically recovered, which greatly facilitates the use of the user and saves a lot of time;
4. The extraction time of Soxhlet extractor is adjustable.

Efficiency of Cellulose Extraction Thimble
Cellulose extraction thimble provided by Hawach Scientific is refined from imported inert cellulose long fiber and cotton wool fiber, using high efficiency and innovative technology highly homogenized model. It is completely free of impurities, and provides with uniform product pores, stable and solid quality, fixed size accurate, mechanical strength, strong retention force. The cellulose extraction thimbles are commonly used for various Soxhlet extractions, rapid solvent extraction, or other similar extraction applications.

Application fields of Soxhlet extractor:

Determination of fat content in aquatic product feed, determination of fat content in leather, determination of succinic acid content in Pinellia ternata, determination of polysaccharide content in Ganoderma lucidum, determination of residual oil content in chemical fiber, determination of fat content in shiitake mushrooms.

Hawach can provide different types of extraction thimble for your choice, If you have any questions for extraction thimble, don’t hesitate to contact us.

Cellulose Extraction Thimble Use In Soxhlet Extractor

Why The Experimenters Should Choose Bottle-Top Dispenser?

The bottle-top dispenser is divided into three types: basic type, organic type, and hydrofluoric acid type, which has covered all the solvents in the laboratory.

Basic Type

The basic type is suitable for a wide range of reagents, including general acid-base solution, low concentration of non-oxidizing strong acid and strong base, such as H3P04/HCI/H2SO4/NaCI and so on. The maximum pressure resistance is 500mbar, the maximum solution viscosity is 500mm 2 / s, and the maximum liquid density is 2.2 g / cm³.

Organic Type

The organic type is suitable for a high concentration of strong acid solutions and a wide range of organic solvents, such as trifluoroacetic acid, chlorine-containing fluorine organic solvents, and peroxide. The maximum pressure resistance is 500mbar, the maximum solution viscosity is 500mm / s, the maximum liquid density is 2.2g / cm³.

Hydrofluoric Acid Type

The hydrofluoric acid type is only suitable for HF solution. Because of the strong corrosion of HF, the piston of the distributor is the ceramic piston, and the suitable reagent bottle should be plastic material with a maximum pressure resistance of 500mbar, maximum solution viscosity resistance of 500mm 2 / s, and maximum liquid density of 3.8g / cm³.

1. The HAWACH bottle-top dispenser can be used to dispense aggressive reagents, including concentrated acids, such as H3PO4, H2SO4 and NaOH, KOH and other salt solutions. It can also dispense a variety of organic solvents.

2. Digital display: very easy to read, can accurately set the dispensing volume and continuously repeat operations (mechanical counting). A red recalibration indicator can indicate an automatic transition to industrial settings.

3. The components of the HAWACH bottle-top dispenser use advanced materials: borosilicate glass, ceramics, platinum-iridium, ethylene tetrafluoroethylene, fluorinated ethylene propylene (rubber), phenolic resin, etc. The discharge tube safety nut is made of polystyrene.

4. Drain tube safety helmet: Screw on the safety helmet after draining to prevent residual liquid from dripping and reduce the risk of contact with harmful reagents.

5. Safety valve: use internal circulation to discharge air bubbles, avoid waste of solution, and ensure dispensing accuracy.

6. Operating rating: maximum vapor pressure 500Mpa, maximum viscosity 500mm2/s, maximum temperature 40℃, maximum concentration 2.2g / cm³.

7. Easy to disassemble and clean, has a replaceable filling valve and can be autoclaved at 121℃.

8. Equipped with multiple bottle adapters as standard, suitable for a variety of reagent bottles

The do’s and don’ts for the use of bottle-top dispensers

1. When installing the drain pipe and the inlet pipe, insert the nozzle straight into the valve, tighten the screw cap to avoid violent installation, and insert the nozzle.

2. Before each use, make sure that the inlet valve and drain pipe and all valves are properly installed and tightened, so as to prevent the piston movement from splashing.

3. Drain the liquid so that the drainpipe is not directed to the operator to ensure safety.

4. Control the piston to move slowly and uniformly when draining liquid, use a suitable container to receive, let the liquid go down the wall.

5. Please stop immediately when you encounter a failure when draining liquid. Do not operate violently to avoid further damage to the bottle-top dispensers.

6. After use, please fasten the safety cap of the discharge pipe to prevent the liquid at the discharge pipe from dripping due to gravity or absorbing water vapor in the air.

7. After use please rotate the scale adjustment ring to the “0” position to ensure safety.

8. Prohibited reagents: HF acid and bromine suspension. (If used, a special bottle-top dispenser is required).

9. Do not attach organic reagents to the surface. If so, wash with water immediately.

10. The suitable temperature for the bottle-top dispenser is 4-50 ℃.

Why The Experimenters Should Choose Bottle-Top Dispenser?

Frequently Asked Questions (FAQ) About QuEChERS Method

1. How can QuEChERS benefit work? (matrix removal and analyte extraction)
The QuEChERS method is a generic sample preparation technique that focuses on matrix removal. Since the QuEChERS method is not analyte-specific, you can prepare samples for analysis of various compounds without spending any time on method development.

2. How long does the QuEChERS program take? (time)
For 25 to 30 samples, the actual extraction and SPE purification process should take no more than 90 minutes. The time-limited step is to weigh the sample into a 50 ml centrifuge tube during the extraction step.

3. Are QuEChERS compatible with my work? (sample preparation selection)
If you want to eliminate matrix noise, the QuEChERS approach is for your work. The technique is particularly effective for solid, semi-solid, viscous liquid mixtures and small amounts of liquid samples.

4. Compared to other food sample preparation techniques – is it expensive?
Not at all. Each sample will cost a few dollars. The QuEChERS approach allows you to use less hazardous solvents in smaller volumes, which eliminates the cost of hazardous solvent disposal and general bulk solvent disposal. At the same time, you will get a better sample purification effect and will help extend the service life of the analysis column and save the cost of purchasing a new column.

5. How to select the appropriate kit for the QuEChERS method?
Select the kit according to the nature of the sample. The MgSO4 / PSA kit can be used for high-water, light-colored, fat-free samples such as apples, oranges, and lettuce. MgSO4/ PSA/C18E kits can be used. These samples are rich in fat and wax, but only light-colored samples, such as coconut, avocado, nuts, and seeds. The MgSO4/PSA/GCB kit can be used to sample colored and low-fat samples (e.g. spinach, berries, chilies). MgSO4 /PSA/GCB/C18E can be used for samples rich in pigment and fat, such as chocolate and black olives.

6. I am not bound by AOAC or EN standards. Which extraction kit should I choose?
Any buffer extraction kit can be used if a large number of pesticides or target analytes are pH dependent. Use the original non-buffering kit, if there are only a few compounds or the target analyte is not pH dependent.

7. What is the difference between AOAC and EN QuEChERS?
Both are buffered and are different from the selection of buffer salt in the extraction step and the sample to the salt and adsorbent ration in the dispersion purification step.

8. Under what circumstances would you choose a 1 ml QuEChERS kit and an 8 ml kit?
To use bulk injection for GC/MS in the lab, the 1 ml kit is suitable and an 8 ml kit requires concentration of the final extract and exchange of the solvent into toluene for GC/MS to enable detection of 10 ng/g pesticides.

9. What is the role of magnesium sulfate in the extraction and dispersion purification process?
During extraction and purification, add the magnesium sulfate to absorb water and also increase the aqueous mixture ionic strength and initiate phase separation from acetonitrile.

10. My QuEChERS analysis included a fair amount of acidic pesticides. Does PSA reduce its recovery? What changes can I make?
PSA adsorbents may retain acid analytes. If this is a problem, you can omit the dSPE step and directly analyze the supernatant in the extraction step. You can also use PSA to compare results with and without dSPE to determine whether the PSA purge is appropriate for your sample.

Frequently Asked Questions (FAQ) About QuEChERS Method

Six Steps To Correctly Use The HAWACH Pipette

A complete pipetting process consists of the following six steps:

1.Tip installation–rotary installation
■ Use a tip with a suitable pipette range. To ensure good sealing, insert the pipette vertically into the tip, rotate it halfway to the left and right, and tighten it. The recommended pipette volume is 35% -100% of the tip within the range. (Multi-channel pipettes are recommended to use imported tips)

2. Volume setting: rough adjustment / fine adjustment
■ Adjusting from large range to small range is the normal adjustment method, just rotate the scale counterclockwise.
■ When adjusting from a small range to a large range, it should first be adjusted to exceed the set volume scale, and then adjusted back to the set volume. (Do not turn the button out of the range, otherwise, it will jam the mechanism and damage the pipette.)

3. Rinse the tips
■ After installing a new tip or increasing the volume value, the liquid is sucked and discharged two or three times, and the adsorption on the inner wall surface of the tip reaches saturation, ensuring the precision and accuracy of the pipetting work;

4. Imbibition
■ Tip immersion depth when pipetting with different volume
• 0.1-2.5ul / 0.5-10ul ≤ 1mm
• 2-20ul / 10-100ul / 20-200ul ≤ 2mm
• 100-1000ul ≤ 3mm
• 1000-5000ul / 2-10ml ≤ 4mm

■ Positive pipetting (low-density solution)
1. Press the button to the stop point;
2. Gently release the button to the starting point to complete the imbibition;
3. Gently press the button to the stop point to drain the liquid; pause for a while and continue to press the button to drain the liquid;
4. Release the button to return to the origin. If necessary, continue pipetting after changing tips.

■ Reverse pipetting (for viscous or volatile liquids)
1. Press the button to the second stop point to imbibe, and gently release the button to the starting point to complete the imbibition. Suck more liquid than set capacity;
2. Gently press the button to the stop point to exclude the liquid with the set capacity;
3. The excess liquid remaining in the tip is discarded with the tip.

5. Drain
The tip is close to the wall of the container. Press the discharge button to the stop point, pause slightly, and then press it to the second stop point. This will ensure that there is no residual liquid in the tip. If there is still residue, the tip needs to be replaced.

6. Remove the tip
■ After removing the pipette tip, set the pipette to a large volume.
After the pipette is operated, there are a few more TIPS to remember:
• Do not use a large-range pipette to transfer small volumes of liquid;
• Use a pipette tip that matches the pipette;
• Bubbles are generated too quickly when the liquid is imbibed, and the liquid immerses into the pipette to corrode the interior;
• The set range must not exceed the valid range of the pipette and damage the pipette;
• Pipettes that have sucked liquids should not be placed flat, and the liquid in the tips will easily contaminate the inside of the pipettes;
• The pipette should be adjusted to a large scale after each experiment to allow the spring to return to the prototype to extend the life of the pipette;
• Check for leaks during use. After imbibing the liquid, suspend it for a few seconds and check whether the liquid level drops. If the liquid leaks, check whether the tip is matched and the spring piston is normal.

Six Steps To Correctly Use The HAWACH Pipette

Why Does The Sample Vial And Septa Quality Are So Important?

According to different factors, Hawach sample vial can be divided into different categories.
1). Due color, the vial can falls into: transparent, brown (brown is mainly used to
avoid light);
2). Due volume: 2ml, 10ml, 20,ml 40 ml;
3). Due diameter: 8mm, 9mm (8-425/9-425 are thread ports), 11mm is clamp/bayonet;
4). Due the writing blank area: there is a writing blank area, there is no writing blank area;
5). Due the glass material: USP1 borosilicate glass (more expensive than domestic glass bottles), transparent color is divided into 7.0 and 5.0, 5.0 is better, transparent glass is all USP1;
6). Due  the type of bottle mouth: thread, buckle, clamp mouth (where the clamp mouth needs the corresponding pliers to be used together).

 

The importance of sample vial quality
If the tolerance is not strictly controlled, the labeled size and wall weight of the autosampler sample vial may be different, which will affect the sample volume in the sample vial, especially important for a small number of samples. HAWACH’s strict tolerance control runs through the entire manufacturing process, from the initial design to the final photoelectric scanning inspection process, to ensure the accuracy of each sample vial and cap specifications.

Harm of using poor quality vials and seals on the autosampler
1. Inconsistent thickness at the bottom of the vial: Inconsistent sampling; damage to the injection tip;
2. Autosampler sequence stops: Mishandling or dropping vials; loss of precious samples
3. Seal leaks are not detected: Sample loss, volatility; may contaminate samples
4. Displaced or misaligned septa: Sample loss; sample contamination
5. Ghost Peaks: Contamination of cap septa

The importance of septum quality
To prevent contamination and to avoid damage, the correct septum selection is crucial. Here are some issues you should pay attention to:
1. Temperature control
At higher temperatures, the septa will degrade and cause sample contamination. Rubber septa are not suitable for high temperature applications，because they only stable below 90℃. Generally, PTFE-lined silicone rubber septa are the best choice for various temperatures.
2. Debris
When the tip diameter is too large compared to the septum or the septum material cannot withstand multiple injections, debris will be generated. At this time, the septum material will fall off into the sample vial and contaminate the sample. Here’s how to prevent debris:
a. Select a PTFE-lined septum to prevent the septum material from entering the sample;
b. Make sure the tip is not damaged;
c. Using pre-perforated septa can almost completely eliminate debris.
d. For highly sensitive samples, we recommend the use of a PTFE-lined (“sandwich”) septum, as the PTFE layer acts as a chemical-resistant barrier.
3. Resealability
Resealing is an important factor to consider when choosing a septum. Taking it in a long term, the PTFE/silicone rubber/PTFE is recommended.
4. Puncture ability
In general, silicone rubber septa are easier to puncture than red and butyl rubber septa. Pre-perforated septum is the best choice, it is the most easy to puncture and reduces the possibility of debris.
5. Cap and septum compatibility

Why Does The Sample Vial And Septa Quality Are So Important?

Working Method Of Flash Column

When water is heated at atmospheric pressure, 100 °C is the highest temperature allowed for liquid water at that pressure. Reheating does not increase the temperature of the water, but only converts it into steam. The heat absorbed by water before it rises to the boiling point is called “sensible heat”, or the saturated water sensible heat. The heat required to convert saturated water into steam at the same atmospheric pressure is called “latent heat.”

However, if the water is heated under a certain pressure, the boiling point of water will be higher than 100 °C, so more sensible heat is required. The higher the pressure, the higher the boiling point of water, and the higher the heat content. The pressure decreases and part of the sensible heat are released. This part of the excess heat will be absorbed in the form of latent heat, causing some water to be “flashed” into steam.

Working principle of the flash column: The method of flash column uses the volatility of each component in the liquid mixture, and uses the heat energy as a medium to partially vaporize it, thereby enriching the light component in the vapor phase and enriching the liquid phase in the liquid phase. The principle of using silica gel as the stationary phase in the flash column is an equilibrium between adsorption and desorption. So if the sample and silica gel adsorption are relatively strong, it is not easy to flow out. This will happen, the back point first out, and the front point after out. Then it’s better to adopt alumina as the stationary phase to prevent samples from leaking and allows the mobile phase passes through.

In fact, in the distillation calculation of the flash column, each theoretical plate must perform such a flash calculation, but at this time the general name is called “equilibrium level” calculation, which is theoretically stricter, and its calculation content is exactly the same Every rigorous or “flash” calculation or “equilibrium level” calculation must meet the following three major balances: mass balance, energy balance, and phase balance.

Therefore, a standard “flash” calculation module can handle both changes in pressure (increasing or decreasing) can also handle heat exchange and work exchange. The internal and external work exchange and heat exchange are mainly reflected in the energy balance, and the mass balance and phase balance mainly determine the vaporization fraction and vapor phase. In addition, there is a very important and difficult task in the “flash” calculation.

Flash column is to determine whether the state you specify is in the vapor-liquid two-phase, or only the vapor-phase or liquid-phase only. Moreover, the calculation of liquid-liquid equilibrium, in general, also requires “flashing” calculations. Of course, some software orders come out because the calculation is more difficult. The above description of “flashing” is only one word, not very rigorous, but relatively more accurate. In short, whether you use PROII, ASPEN, or H “YSIS, Flash” calculation is really its most basic core.
Working Method Of Flash Column

To Have A Comprehensive Understanding Of HPLC Columns

1.History of HPLC columns
In the mid 1870s, HPLC instruments began to appear. The main filler: 10 μm amorphous silica particles. In the late 1970s, reversed-phase liquid chromatography was developed. In the 1980s, HPLC was widely used for the separation of compounds. The main filler: spherical silica gel with a particle size of 5-10 μm. In the early 1990s, high-purity silica gel with a particle size of 5 μm, the so-called B-type silica gel, was developed and became the standard for fillers in this industry. This B-type silica gel contains trace amounts of metal. In the late 1990s, in order to meet the needs of rapid separation, 3 μm or 3.5 μm spherical silica gel was developed, and its function and performance gradually gained people’s approval and acceptance. In the early 21st century, in order to meet the ultra-fast separation requirements, fillers with a particle size of less than 2 μm were developed, and monolithic columns, inorganic and organic hybrid silica gels were developed.

At present, the popular HPLC silica gel matrix filler for analysis on the market is mainly type B silica gel.

2.Classification of chromatography
Liquid chromatography separation methods can be roughly divided into normal phase chromatography, reversed phase chromatography, ion exchange chromatography, hydrophobic interaction chromatography, volume exclusion chromatography, affinity chromatography and chiral chromatography. In high performance liquid chromatography, normal phase chromatography and reversed phase chromatography are the most widely used, and reversed phase chromatography is the most important.

3.Principle of chromatographic separation
Separation principle of normal phase chromatography: According to the difference of the solute polarities, the solutes are separated on the adsorbent.

Separation principle of reversed-phase chromatography: The solutes are separated according to the differences in the partition coefficients between the mobile and stationary phases due to the different solute hydrophobicity.

4.Silicone matrix and polymer matrix
Two popular fillers are made of silicone matrix material and polymer matrix material with the following features.

4.1 Silicone matrix material
1. The most widely used matrix material
2. High mechanical strength and high specific surface area
3. Can use direct and extensive surface bonding reactions to meet the needs of normal phase, reversed phase, ion exchange, hydrophobic interaction chromatography and volume exclusion chromatography.
4. High efficient
5. Good reproducibility
6. PH scope of application ph2-8
7. Has a surface active and acidic silicon base that easily causes tailing of strongly alkaline substances

Influence of Silicone Shape
1. Amorphous silicone: Original HPLC packing; Particle size> 5μm; Poor bed stability; Small specific surface area; Cheap
2. Spherical silica gel: Modern HPLC packing; Small particle size (5μm, 3μm, <2μm); Reproducible; Good stability; High separation efficiency

Influence of silica purity
The purity of silica gel is most important for the separation of highly polar compounds. Previously low-purity silica gels are called A-type silica gels). A-type silica gels are prepared from metal silica gel salts, have a high metal content, and can be used to separate neutral compounds from non-ionic compounds.

Silica gel with high purity and weak acidity (called B-type silica gel). This silica gel is prepared by a metal-free process and contains only a trace amount of metal. It is recommended for the separation of ionic compounds and ionizable compounds, especially alkaline. Metal impurities cause asymmetric or tailing peaks in the separation of integrator and basic compounds.

4.2 Polymer matrix material
1. Crosslinked styrene, divinylbenzene and methacrylic acid esters
2. Good PH stability: PH1-13
3. Surface chemical treatment can be performed in a wide range to meet the needs of reversed-phase chromatography, ion-exchange chromatography, hydrophobic interaction chromatography, and size exclusion chromatography.
4. Better peak shape for strongly alkaline substances at moderate pH
5. The volume of the filler varies with the mobile phase, such as expansion or contraction.
6. Low separation efficiency compared to silica gel
7. Poor reproducibility

5.Comparison between HPLC and classic liquid chromatography
I. High pressure: When the liquid mobile phase passes through the chromatographic column of a HPLC, it will encounter great resistance. To quickly pass through a HPLC column, high pressure must be applied to the carrier liquid.
2. High speed: The analysis speed is fast, and the carrier liquid speed is much faster than traditional liquid chromatography. Generally speaking, the analysis of HPLC samples can be completed within 15-30 minutes, and some samples can be completed within 5 minutes, usually less than 1 hour.
3. High efficiency: The choice of stationary phase and mobile phase can achieve the best separation effect, which is several times more than that of industrial distillation column and gas chromatography.
4. High sensitivity: UV detector can reach 0.01ng.
5. Wide application: Use HPLC to analyze more than 70% of organic compounds, especially suitable for the separation and analysis of compounds with high boiling points, large molecules, strong polarity, and poor thermal stability.
6. The HPLC column can be reused: one column can separate different compounds.
7. Small sample size and easy recovery: The sample will not be damaged after passing through the HPLC column, and a single component can be collected or prepared.

To Have A Comprehensive Understanding Of HPLC Columns

Method And Principle Of Solid Phase Extraction Column

Solid phase extraction column (SPE) is a kind of sample pretreatment device developed from chromatography column for extraction, separation, and concentration. Thermo chromatographic column and Waters chromatographic column are commonly used in the experiment. It is mainly used for the pretreatment of target compounds in various kinds of food, agricultural and livestock products, environmental samples, and biological samples.

In order to separate and enrich the target compounds, the spe apparatus used solid adsorbents to adsorb the target compounds in the liquid sample, separated them from the matrix and interfering compounds in the spe column of sample c18, and then eluted them with elution solution or desorption by heating.

Compared with liquid-liquid extraction, spe has many advantages: spe does not need a large number of insoluble solvents and does not produce emulsification in the treatment process. It USES highly selective adsorbent (fixed phase), which can significantly reduce the amount of solvent, simplify the sample processing, and reduce the cost. Generally speaking, the time of spe is 1/2 of that of liquid-liquid extraction and the cost is 1/5 of that of liquid-liquid extraction. The disadvantage is that the recovery and precision of the target compound are lower than that of liquid-liquid extraction.

The model and principle of solid phase extraction
Solid-phase extraction is essentially a liquid chromatography separation, the main separation mode is the same as liquid chromatography, can be divided into positive phase (adsorbent polarity is greater than the polarity of the eluent), reverse phase (adsorbent polarity is less than the polarity of the eluent), ion exchange and adsorption. The adsorbents used in spe are also the same as the fixed phase commonly used in liquid chromatography, except that the particle size is different.

The adsorbents used in normal solid phase extraction are polar and are used to extract (retain) polar substances. Target when positive phase extraction using c18 solid-phase extraction small column compound how to keep on the adsorbent, depend on the polar functional groups of target compounds and the interaction between polar functional groups on the surface of the adsorbent, including the hydrogen bond, PI, PI bond interaction, dipole-dipole interactions, and dipole – induced dipole interaction and another polarity – polarity effect. Polar compounds can be adsorbed from non-polar solvent samples by positive solid-phase extraction.

Usage of spe column:
The simplest spe can be done manually by attaching a syringe to the top of the spe column and squeezing the fluid out of the column. In addition, a positive or negative pressure spe device can be used to perform spe on bulk samples. With the development of science and technology and the increase of sample quantity, more and more analysis laboratories begin to use automatic spe, especially multi-channel spe to process batch samples.

Principle of spe column:
SPE technology is based on the theory of liquid-solid phase chromatography, which USES selective adsorption and elution to enrich, separate, and purify samples. It is a physical extraction process involving liquid and solid phases. It can also be approximated as a simple chromatographic process.SPE is the separation principle of selective adsorption and selective elution by liquid chromatography.

The more common method is to make the liquid sample solution through the adsorbent, retain the measured substance, then choose the appropriate strength of solvents to wash away impurities, and then use a small number of solvents to quickly elute the measured substance to achieve rapid separation purification and concentration of the purpose. It can also selectively absorb interfering impurities and cause the measured substance to flow out. Or adsorb both the impurity and the measured substance, eluting the measured substance selectively in an appropriate solvent.

The general process for extraction column use:
Firstly, the sample was treated, the sample was activated on the extraction column, the processed sample was added slowly, the column was cleaned, a few times for elution, then the eluent was blow-dried with a nitrogen blower, the volume was redetermined, and the analysis was carried out on the machine.

At present, the extraction column is applied in the field of food safety in China, such as the analysis of drug residues of various antibiotics and antimicrobial drugs in various kinds of food. Analysis of pesticide residues in agricultural and sideline products; Analysis of the amount of legal and illegal additives in many kinds of food. In the field of pharmaceutical research and analysis, the pharmacokinetic, pharmacokinetic data analysis, and pharmaceutical composition analysis is widely used in drug research and development. Because it is easy to use and practical, it is more and more widely used.

Method And Principle Of Solid Phase Extraction Column 

Filtration Process Of Active Carbon Block Filter Cartridge

Hawach activated carbon block filter cartridge is a kind of commonly used water treatment equipment. As the pre-treatment of water treatment desalination system, it can adsorb the residual chlorine which cannot be removed in the pre-stage filtration, which can effectively ensure the service life of the post-stage equipment, improve the effluent quality, prevent pollution, especially prevent the pollution of free residual chlorine poisoning of post-stage reverse osmosis membrane, ion exchange resin and so on. It has outstanding properties for odour, organic matter, and residual chlorine in water. It also plays a good role in reducing the turbidity, chromaticity, purification of water quality and pollution to the follow-up system.
#Filtration Process Of Active Carbon Block Filter Cartridge#

10 Steps To Clean Membrane Filter

The frequency of filter membrane cleaning is related to the perfection of pretreatment measures. The more complete the pretreatment measures, the longer the cleaning interval; conversely, the higher the cleaning frequency.

1. The chemical cleaning cycle depends on the degree of membrane fouling.
2. The common cleaning liquid formula is as follows:
Alkali washing solution: 0.1 ~ 0.5% NaOH solution. Acid pickling solution: 0.2% HCI or 1% citric acid solution (selected according to the actual situation). Oxidant solution: 500 ~ 1000mg / L (effective chlorine concentration) NaClO solution.
3. According to the instructions of the cleaning solution above, prepare the cleaning solution according to the proportion in the chemical cleaning box, and mix thoroughly to control the pH and temperature.
4. Reduce the liquid level in the membrane tank to the lowest level, or drain the water in the membrane tank.
5. In the way of backwash, the chemical cleaning solution penetrates the membrane from the inside of the hollow fiber under the pressure of the cleaning liquid pump and accumulates in the membrane tank until the membrane module is flooded.
6. Let the cleaning solution soak the membrane filaments in the membrane tank for 2 ~ 4 hours, while soaking, it can be aerated to enhance the cleaning effect.

#10 Steps To Clean Membrane Filter#

Application And Operation Process Of Wet-strengthened Filter Paper

Paper chromatography uses filter paper as an inert support. The filter paper fiber has a strong affinity with water, and can absorb about 22% of water, and 6 to 7% of the water is hydrogen bonded to the hydroxyl group of cellulose, which is difficult to remove under normal conditions. The affinity with organic solvents is very weak, so the general paper chromatography actually uses the binding phase of filter paper fibers as the stationary phase and the organic solvent as the mobile phase.

When the mobile phase passes the sample along the paper, the solute at the sample point is in water and the organic phase is continuously distributed. Part of the sample moves with the mobile phase and enters the solute-free zone. At this time, it is redistributed, and part of the solute enters the stationary phase (water phase) from the mobile phase. With the continuous movement of the mobile phase, various parts are continuously distributed according to their respective distribution coefficients, and move along the mobile phase, so that the material is separated and purified.

#Application And Operation Process Of Wet-strengthened Filter Paper#

About The Usage, Type And Features Of Syringe Filter

HAWACH specializes in lab experimental consumables that are engineered and built to meet the industry specific needs of small and medium size companies. We provide high value, one-stop shopping systems that are easy to use, easy to clean and easy to maintain for the lowest total cost of ownership.

Being a single-use filter cartridge located at the end of a syringe, syringe filter is a good tool to remove small particles from a sample before analysis in the lab. With the luer lock which can fit the secure fit attach the syringe, syringe filters provide efficient filtration in many fields, such as pharmaceutical, biotechnology and agricultural laboratories.

You can find syringe filters with different types of membrane. So before you select a syringe filter, you need to know what kind of the filter membrane is appropriated for your application.

To handle different applications, the syringe filter's membrane can be made of various materials. The most common filter materials are cellulose acetate and polyethersulfone. Depend on their chemical compatibility, flow rate, and burst pressure, we can tell the differences of the membranes. You may find out the different capacity of the filter, as the material will change the effective filtration area. The design of filter body, different filter and pore size should be considered too.

Here I would like to share the Hawach syringe filter, like the usgae, type and features.

Use

HAWACH syringe filters is mainly used for filtration of mobile phase and samples in chromatographic analysis. It has a good effect on protecting the chromatographic column, infusion pump tube system, and injection valve from being contaminated. It is widely used in gravimetric analysis, microanalysis, colloid separation and sterility test.

Type

There are two types, water system and organic media system.

Characteristics of filter membrane material in syringe filter

A. PTFE (polytetrafluoroethylene)

Performance: it is all solvents-resistant, with low solubility and suitable for water system and various organic solvents. It has the characteristics of breathable and water-tight, large air flux, high particle retention rate, good temperature resistance, resistance to strong acids, alkalis, organic solvents and oxidants, aging resistance and non-stickiness, non-flammability and non-toxicity, and biocompatibility. In environmental protection, energy, pharmaceutical, chemical and electronics etc. can find its related products.

B. Water-based PES (Polyethersulfone)

Performance: It has high chemical and thermal stability, fast flow rate, strong acid and alkali resistance (pH range 1-14); has high mechanical strength.

C. Organic nylon 6

Performance: Good hydrophilicity, acid and alkali resistance, antioxidant. Not only for aqueous solutions containing acid and alkali, but also for organic solvents such as alcohols, hydrocarbons, lipids, phenols, and ketones.

D. Organic nylon 66

Performance: Better than domestic nylon 6. This product is suitable for most organic solvents and aqueous solutions. It can be used for organic solvents such as strong acid, 70% ethanol, dichloromethane, with high temperature resistance, good strength and stable chemical properties.

E. PVDF

Performance: Polyvinylidene fluoride membrane is chemically stable and inert, suitable for chemically corrosive organic solvents, strong acids and alkali solutions, and sample preparation in liquid chromatography analysis. It has hydrophobic properties and can filter out air and gases Moisture content. With strong strength and operability, the polyvinylidene fluoride membrane can withstand high temperatures of 130 degrees.

#Syringe Filter#