How To Use Vacuum Filtration?

 In the laboratory vacuum filtration experiment, customers often filter some samples with a lot of particles or very viscous. When these samples are filtered, they often fail to pump.

This situation is generally due to the liquid in the liquid. It is caused by the solids completely blocking the microporous filter membrane. In this case, the following methods are generally recommended:
1. Dilute the sample: In the detection and filtration of suspended solids, it is often the case that the high particle content in the water sample blocks the microporous filter membrane and can not move. You can dilute the sample that needs to be filtered and then filter it.
2. Increase the filtration area: now the common vacuum filter bottle on the market can be placed with a 50mm diameter microporous filter membrane. Replace a set of filters that can place a larger diameter filter membrane, so that the solids in the sample are not so easy to block the filter. membrane.
3. Increase the vacuum degree: replace a vacuum filter pump with a higher vacuum degree. The suction filter pump with a higher vacuum degree has more force during suction and may alleviate the phenomenon of inability to filter to a certain extent.

300ml glass solvent filters are to suck out the solvent and it will evaporate. The loss of solvent pressure filtration is to squeeze out the solvent. Generally, there will be more solvent residue in the filter cake. It is better to use a centrifuge to separate the material, fully enclosed, and automatically unloading. Both environmental protection and low labor intensity. If you don’t care whether the loss of solvent and residue is the same as pressure filtration and reduced pressure filtration, both can be used.

Process

1. Install the instrument, check whether the connection between the Buchner funnel and the suction filter bottle is tight and whether the connection port of the suction pump is leaking;
2. Trim the filter paper to be slightly smaller than the Buchner funnel but cover all the holes, add distilled water dropwise to wet the filter paper, and slightly open the exhaust valve to make the filter paper and the funnel tightly connected;
3. You should turn on the air pump switch, pour the solid-liquid mixture, and start suction filtration. Try to keep the material to be filtered in the center of the Buchner funnel to prevent it from flowing directly through the gap between the funnel and the filter paper without being filtered.
4. After filtering, first remove the suction filter bottle to take over, and then turn off the suction pump.
5. When taking out solids from the funnel, remove the funnel from the suction filter flask, hold the funnel tube in your left hand, turn it upside down, and “slap” the left hand with your right hand to make the solids fall onto the clean paper or watch glass together with the filter paper . Remove the filter paper and dry the solid.
The solution in the suction filter bottle should be poured out from the upper mouth.

Precautions
1. When installing the instrument, the inclined surface of the lower end of the funnel tube should face the branch nozzle. But not too close to avoid the filtrate being pumped away.
2. When the filtered solution has strong acidity, strong alkalinity, or strong oxidation, glass fiber should be used instead of filter paper or glass sand funnel should be used instead of the Buchner funnel.
3. It is not suitable to filter the colloidal precipitate or the precipitate with too small particles.
4. In the process of suction filtration, when cracks appear in the solid layer in the funnel, use glass plugs or the like to compress them to block the cracks. If it is not compacted, the suction efficiency will be reduced.
5. When stopping suction filtration, first unscrew the cock on the safety bottle to restore normal pressure, and then close the suction pump.

How To Use Vacuum Filtration?

Use of Laboratory Extraction Thimble

 Soxhlet extraction is a form of continuous solid-liquid extraction in which a solvent is used to extract the desired compound from a solid material. Although there are other methods for extraction, such as adding solids directly to the solvent and adding filtration, Soxhlet synthesis is particularly effective when the solubility in the extraction solvent is limited, and the solvent will be repeatedly used during the extraction process.

The principle of Soxhlet extraction

Heat the flask containing the solvent to evaporate the solvent, and the solvent flows along the side arm until it reaches the condenser. The steam condenses and drips into the thimble in the extraction thimble, which should contain the material to be extracted.

The material to be extracted should be ground as much as possible, and the required compounds can be easily removed. Over time, the solvent will evaporate and concentrate from the flask to fill the extraction thimble. After filling the Soxhlet, the liquid content will be emptied back into the solvent bottle along with any compounds dissolved in the solvent.

This process will continue to circulate, and the solvent will evaporate from the flask and be refilled. Over time, all soluble components will be extracted into the round bottom flask. The compounds can then be separated by rotary evaporation. One of the most common uses of the extraction thimble is to obtain compounds from natural products, such as extracting compounds from seeds or fruits.

Key points of using extraction thimble

1. The size of the flask and the amount of solvent must be larger than the Soxhlet extraction capacity to avoid boiling and drying the solvent bottle and keeping the extracted components in solution when the extraction thimble is running. The choice of solvent is critical to the success of extraction.
2. Crushing, grinding, or shredding the extract can greatly reduce the time required for extraction. The solid is held in a sleeve usually made of cellulose. If you want to quantify the number of certain substances in the extract, the thimble may also have an internal standard added.
3. Firmly clamp the round bottom flask or pressurized pellet containing the solvent and stirring rod on the heat source. It is usually desirable to be able to remove the heat source at the end of the reaction, using a laboratory jack.
4. Soxhlet extraction may last an hour or may last several days, so the experiment needs to be prepared for extraction. The heat source needs to be protected.
5. In order to cool the solvent vapor in the condenser, an effective condenser is required.

Extraction thimbles are laboratory equipment designed to process certain solids. These devices continuously process samples with solvents over a period of hours or days to extract target compounds. They are commonly used by chemists in various fields of sample testing, analysis, quality control, and related applications. As a supplier of laboratory equipment, Hawach can provide various sizes of accessories and accessories.

Use of Laboratory Extraction ThimbleUse of Laboratory Extraction Thimble

Material And Cleaning Procedures For Sample Vial

Hawach sample vials are manufactured with high-quality borosilicate glass after precise design, the use of professional technology, and strict technical specifications. Low free ion content, low expansion coefficient, and very high chemical resistance. The unique thread design can ensure the consistency of the seal, and strict quality guarantees the dimensional consistency between batches.

1. Borosilicate glasses: Chemical inert glass is widely used in laboratory, especially chromatographic analysis. It is mainly composed of silicon and oxygen and some boron and sodium, which has low dissolution and linear expansion coefficient.

2. Salinized or deactivated glass: It has strong hydrophobicity and inertia on its glass surface, thus it can be applied to long-term sample storage and trace analysis.

3. Threaded sample vial: Reusable sealing method that is less harmful than the clamp cover, and does not require additional tools. The thread cover sample vials distinguished by different thread specifications, which are defined by the Glass Packaging Association (GPI). For example, the 9-425 sample vial thread diameter is about 9 mm, the thread type is 425.

4. Threaded port sample vial pad: An automatic injection design hole cover, a solid cover for sample storage design, and an integrated PP cover are also available. This puncturable thread cover is designed for a single injection without the need for cover assembly, which can save experimental preparation time.

5. Clamp sample vial: Sealing with aluminum cover is relatively cheap. When the correct clamp is tight, it can be used for long time storage to provide sealing. The clamp cover cannot be reused and needs a larger force clamp.

Cleaning Procedures and Tips of Sample Vial

In practice, sample vial cleaning usually wastes a lot of time, reduces working efficiency, and sometimes results in deviation of experimental results due to the lack of cleanliness of chromatographic sample vials after cleaning.

The cleaning of the chromatographic sample vials is very important. If the cleaning is not clean, it may affect the next measurement, so we must master the cleaning method of chromatographic sample vials and select the cleaning method according to the degree of pollution according to the washing method of glass instruments. There are some cleaning tips for sample vials:

Tip one: Rinse it with tap water several times; then put it in a beaker filled with pure water for 15 minutes; change water and ultrasound for 15 minutes; put it in a beaker filled with anhydrous ethanol, and finally take out the natural air drying.

Tip two: first soak with methanol (chromatographic purity), and ultrasonic cleaning for 20 minutes, then dry methanol; fill the chromatographic sample vial with water, ultrasonic cleaning for 20 minutes, then dry the water; finally, dry the chromatographic sample vial.

Tip three: washing method of the chromatographic sample vial is the same as that of liquid, first use medical alcohol to soak for more than 4 hours, then ultrasonic for half an hour, then pour out medical alcohol, use water ultrasonic for half an hour, rinse with water and dry.

Material And Cleaning Procedures For Sample Vial

Common Problems In Use Of HPLC Chromatographic Column

 For a commonly used HPLC chromatographic column, how should I activate and maintain it when I get a new HPLC chromatographic column? Why do you want to do this?

Activation of a new column is actually an equilibrium process. In addition to balancing with the mobile phase, it is sometimes necessary to equilibrate the new column with the sample to be tested, especially for the determination of peptides with relatively high molecular weight.

Because of the high molecular weight substance molecules, the diffusion speed is slow, and the time required for equilibrium is correspondingly longer. The specific balance method is also very simple. Inject samples several times until the peak area and retention time are stable, and then perform the formal sample injection measurement.

If you want to speed up the equilibration time, increase the concentration of the injection sample used for equilibration, or continuously inject multiple injections without waiting for the elution to complete. Equilibrate the new column with the analyte in order to saturate the adsorption capacity of non-specific adsorption sites on the surface of the silica matrix filler.

What are the HPLC chromatographic column technologies? For example, tail sealing, etc., where are these technologies reflected in the application?

HPLC chromatographic column technology includes packing technology and packing technology. It goes without saying that the packing technology has a decisive influence on the separation performance and selectivity of the HPLC chromatographic column. The packing technology is not as simple as imagined.

Different stationary phases, different particle diameters, different inner diameters, and lengths of the column tube, the packing process is different, it is necessary to pack a compact, stable, and uniform column bed. Art requires accumulation of experience.

Where is the gap in HPLC chromatographic column technology?
Answer: There are actually certain skills and procedures for liquid HPLC chromatography column packing, and there may be some luck. Generally, use the high-pressure homogenization method for filling. That is, the filler can be uniformly suspended in the solvent. Then use instant high-pressure compaction, which actually uses different proportions of homogenized liquid and appropriate pressure.

If the pressure is too high, the particles will be broken, the pressure will be too small, and the number of plates will be small. At the same time, the pressure needs to be stable, otherwise, the distribution will be uneven and the tailing will be serious. At the same time, the level of head flatness. Put on the sleeve and it’s ready to use.

Under what circumstances can the column be cleaned? Originally discussed this issue, I also removed it and cleaned it, but I saw that the front part of the HPLC chromatographic column was more contaminated, so I scraped it with a blade, and then installed the cleaned sieve. The problem is solved, but will the service life be reduced?

If the HPLC chromatographic column head is contaminated, remove the contaminated one, and install some packing. Because you scraped some fillers, the number of micro-plates is reduced. You don’t shave too much, only the surface maybe some dirt, so the problem is solved. But in the future, there will be the same problem. If you hang it again, it will be scratched accidentally, which will affect the column efficiency. It is recommended to install a pre-column.

Common Problems In Use Of HPLC Chromatographic Column

Four Tips On The Choice Of SPE Cartridge

Before talking about the choice of SPE cartridge, HAWACH will discuss the SPE cartridge and its capacity first.

About the SPE cartridge and its capacity
SPE cartridge is a sample pretreatment equipment developed from chromatography columns for extraction, separation, and concentration. It is mainly used in sample pretreatment of target compounds in various food, agricultural and livestock products, environmental samples, and biological samples, etc.

The capacity of the SPE cartridge refers to the adsorption capacity of the cartridge packing. For an SPE cartridge based on silica gel, its capacity is generally 1~5 mg/100 mg, that is, the cartridge capacity is 1%~5% of the mass of the packing. The bonded silica gel ion exchange adsorbent packing capacity is meq/g, that is, the capacity of each gram of packing is X milliequivalents. The capacity of this type of packing is usually 0.5 to 1.5 meq/g.

How to choose the SPE cartridge
In short, the selection must be made according to the nature of the sample and the solvent background. Generally speaking, there is no uniform regulation about what solvent to be used for the activation and elution of the solid phase extraction packing. Please refer to the national standard, pharmacopeia, or validated method based on your analysis.

1. Activation: There are two purposes for the activation of the SPE cartridge, one is to infiltrate the packing so that the sample solution can flow through it; the second purpose is to clean the interfering impurities and solvent residues on the SPE cartridge.

2. Sample loading: Let the sample solution flow through the solid phase extraction column to allow the packing to adsorb the target substance. Generally, the flow rate should not be too fast, otherwise, the adsorption is not complete and the recovery rate will below.

3. Washing: It is necessary to choose a suitable solvent, which will not wash off the target product adsorbed on the SPE cartridge packing, but also wash away some interfering impurities. This choice is also based on existing methods and there is no uniform standard.

4. Elution: Choose a suitable solvent to elute the target substance adsorbed on the SPE cartridge packing (most of the time you need to use a test tube to collect). This solvent is also determined according to the specific experimental method and cannot be uniformly specified.

If the above cannot clear your doubts, welcome to contact HAWACH for more, who has years of experimental experience.

Four Tips On The Choice Of SPE Cartridge

About the Mixed Cellulose Ester Filter Membrane

 Filter membrane is essential to use with syringe filter in the syringe to filter chemically turbid solution samples, most commonly used in chemical HPLC-MS/GC-MS analysis of liquid and gas dust removal, sterilization filtration, biological sample preparation, filtering of tissue culture medium, microbial media, buffer solutions, etc.

There are different filter membranes adopted in the syringe filter to meet different requirements. Today, HAWACH will mainly discuss the mixed cellulose ester(MCE) filter membrane in the syringe filter.

The mixed cellulose ester filter membrane is made of refined nitrocellulose, added with an appropriate amount of cellulose acetate, acetone, n-butanol, ethanol, etc. It is hydrophilic, non-toxic, and hygienic. It is a porous membrane filter material with a comparative pore size distribution and its uniform penetrating micropores with a microporosity of up to 80‰. The MCE filter membrane is mainly used for the filtration of water-based solutions, so it is also called a water-based membrane. This product is flammable. When storing, it should be sealed, moisture-proof, and fire-proof.

The main application of mixed cellulose ester filter membrane

1. The pharmaceutical industry requires autoclaving, water injection, large infusion, traditional Chinese medicine extraction, and beverage filtration to remove particles, which can improve the internal quality of drugs and the pass rate of clarity and sterilization of heat sensitive drugs (insulin ATP, coenzyme A, and other biochemical preparations). Use 0.45 micron filter membrane (or 0.3 microns, 0.2 micron filter membrane), the sterility test of antibiotic film method.

2. Medical and sanitation, the detection of human body fluids and bloodworms, and the detection of coli-group in drinking water, surface water, and well water.

3.Analysis and determination of particles and oil insoluble matter in solution, and determination of water pollution index.

4.Applied to research departments such as somatic cell hybridization and mitochondrial complementation to predict heterosis.

5.Fine filtration of high-purity water in the electronics industry.

6. The filter membrane must be in a wet state when filtering liquid. If the filter membrane becomes dry due to disinfection, it must be wetted with sterile water. If the wetting is not good, the flow rate must be disinfected before the sterilization filtration. And then carry out sterilization filtration in a sterile room, which should be carried out strictly in accordance with the sterilization operating procedures, with a nominal pore size of 0.45 microns, 0.3 microns, and 0.2 microns, and escherichia coli with a nominal pore size of 0.65 microns.

7.The membrane is resistant to high temperatures of 120 degrees, flammable, not resistant to acids and alkalis, and not resistant to solvents. It is only suitable for aqueous solutions (PH2-10), oils, air, fruit juices, and wines, etc. Whether the filter material is suitable for the filter membrane before use should be well noted.

8.When the filter residue is below 0.025 microns, it is not advisable to use a microporous membrane to filter. It only has an adsorption effect on heat source viruses and cannot be completely removed.

9.When the filter is used, the original air inside the filter should be discharged when the material liquid enters the filter, otherwise, the filter speed will be affected.

10.Pay attention to problems when using natural pressure, pressurization, vacuum, and negative pressure to prevent bacteria and particles in the outside air from inhaling and polluting the filtrate when vacuuming. For pressure filtration, the faster the filtration rate, the faster the pressure, the faster the filtration rate. For high pressure, we should consider whether the main body of the filter is intact, generally not more than 0.3MPa/c㎡.

11. Put the filter membrane into the container, soak it in distilled water at about 70 degrees to make it wet for several hours (about 4 hours) and then wash it with distilled water once for use.

About the Mixed Cellulose Ester Filter Membrane

Introduction And Application Fields Of Chemical Filter Paper

Introduction And Application Fields Of Chemical Filter Paper

Filter paper is the general term for ultra-thin filter materials. Chemical filter paper can be made of various fiber materials, including wood pulp paper (made of plant fibers), glass fiber paper (made of ultra-fine glass fiber), and PP paper ( Made of ultra-fine polypropylene material), and so on. Non-woven fabrics are originally formed by spinning a chemical fiber material, which is different from the principle of textile molding, so it is called non-woven fabric (also called non-woven fabric, non-woven fabric). It was first used as clothing material and later borrowed as a filter material.

The relationship between chemical filter paper and the non-woven fabric is PP paper, which is a kind of chemical filter paper. Originally, non-woven fabrics do not have to be called a kind of chemical filter paper. In international trade, the concept of “cloth” belongs to textiles and is restricted in import and export procedures, so it is called a kind of “filter paper”.

As an effective filter medium, the filter paper is widely used in various fields, such as industry, food, medical treatment, hygiene, environmental protection, and so on. There is mainly grinder filter paper for the grinder processing industry, automotive processing industry filter paper, automotive filter paper, air filter paper, grinding fluid filter paper, emulsion filter paper, transformer filter paper, edible frying oil filter paper.

Chemical filter paper filtration is actually chromatography:

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

When the mobile phase passes through the sample along with the paper, the solute on the sample point is the water and the organic phase are 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 substances can be separated and purified, and water and alcohol can be filtered.

Laboratory chemical filter paper is a kind of essential need in the processing of separation and purification. Throughout the different stages of chromatography, As the must-have products for lab and industrial process, the chemical filter paper can be used in solvent filtering, cellulose analysis, and other applications that involves separation and purification.

The purification products but also come in different variants for different purposes. Hawach provides the complete range of different types of chemical filter paper with varying capacities, different filtration levels. And all the products which are made for specific samples in every particular application will highly beneficial the whole chromatographic process.

Introduction And Application Fields Of Chemical Filter Paper

Boxed Sterile Filter Tips

Introduction of low retention tips

Hawach pipette tips are universal fit, the tips can be used with most of the brands in single-channel pipette and multi-channel pipette. such as Eppendorf, Gilson, Rainin, Biohit, Brand, Finpipette, etc. Hawach pipette tips are available in three different packages, respectively are bags, racks, and stacked packages. Bag packaging is the most cost-effective option; Rack/box packaging is convenient to use and stock; Stack packaging is economic for tips stock management.

Features

1. Electron Beam Sterilization, this way make sure the sterile tips with no chemical residue after sterilization, no interference for virus detection
2. Non-pyrogenic, Non-endotoxin, DNase/RNase free
3. 100,000 class clean room for production and packaging
4. Universal fit with most pipettes on the market
5. Super fine grinding molding technology which does not need agent demolding ensures smooth inner wall of low retention tips with minimum liquid residue and precise liquid absorption
6. Pipette tips made of virgin PP with high transparency and wide chemical resistance
7. PE sintered filter as a barrier to against aerosol, which eliminates the risk of cross-contamination between the sample and the pipette
8. Filtered pipette tips can be used for suck up of organic solvent products
9. Optimized pore size: ensures smooth absorption of sterile tips. Innovative design, which ensures good flexibility, good sealing, and compatibility of the filtered pipette tip
10. Wide size range: size 10ul, 10ul extended, 200ul, 300ul, 1000ul, 1250ul. Available in standard and low retention tips
11. Wide packaging range of sterile tips: bags, rack, and stack to choose
Bag packaging is the most cost-effective option
Innovative design and special molding technology, which ensures precise and smooth adsorption of low retention tips
Special electric beam sterilization technology ensures the sterility property of our pipette tip box
12. OEM service available

Boxed Sterile Filter Tips

Performance And Quality Commitments of Luer Lock Syringe Filter

Performance And Quality Commitments of Luer lock syringe filter

Syringe filters are suitable for water filtration in electronics, microelectronics, and semiconductor industries, as well as filtration of tissue culture media, liquid medicines, beverages, high-purity chemicals, water and organic solvent mobile phases.

There is no need to change the filter membrane and clean the filter, saving working time. It is mainly used in the filtration of mobile phase and samples in chromatographic analysis, pre-filtration of mobile phase and samples in chromatographic analysis, sample pre-filtration, clarification and removal of particles, and sterilization and filtration of liquids and gases.

Reliable Performance

The glass fiber Luer lock syringe filter is a natural hydrophobic filter medium, which has the characteristics of large flux and large amount of dirt, and is suitable for conventional filtration of organic solvents such as high particle content and strong alkalinity.

It can be used for chemical laboratory analysis of pre-filtration, can be matched with other terminal filters, especially for strong alkaline viscous solution filtration. It has the characteristics of natural hydrophobicity, high flux, high pollutant uptake, good mechanical strength and so on.

Technical Support

Hawach constantly adopts advanced design concept and excellent product technology to guarantee the quality of product. Hawach uses glass fiber membrane as filter materials, and chooses polypropylene as shell materials.

Quality Commitments of Luer lock syringe filter

Hawach glass fiber Luer lock syringe filter is a fast, convenient and reliable filter tool used in laboratory. It is beautiful and light in appearance and high in cleanliness. It is mainly used for sample pre-filtration, clear removal of particles, liquids and gases. It is also a recommended method for filtering HPLC、GC small samples.

According to sterilization method can be divided into sterilization and non-sterilization.The regenerated cellulose membrane is the best choice for DMSO compatibility. The surfactant-free cellulose acetate membranes (SFCA) provide low protein binding. And it provides with natural hydrophilicity of nylon membrane and low extract. Meanwhile, PTFE film provides excellent chemical resistance and natural hydrophobic membrane for ventilation or filtration of gases. What’s more, it is manufactured in accordance with ISO 9001、ISO 9002 standards.

Service Commitments of Luer lock syringe filter

It is available in quality guarantee period of 18 months, life free maintenance. During the warranty period, except for human factors, any defects or failures caused by improper instrument design, material or process are repaired or replaced free of charge. Hawach promises that response within 10 minutes after receiving user notification of failure of the instrument provided. And Hawach ensure timely provision of spare parts and breakable parts at favorable prices to customers.

The conventional aperture is 0.22(μm) and 0.45(μm), the maximum operating temperature is up to 180°C, and the suitable pH range is PH4-14. The filtration capacity of glass fiber syringe filter is faster than standard syringe filter, which can easily and quickly filter samples that are difficult to filter. It can be used alone or in conjunction with the final membrane filter to increase flow rate and handling capacity.

Performance And Quality Commitments of Luer Lock Syringe Filter