The Brief Introduction to SPE Cartridges

SPE cartridges, with a full name of Solid Phase extraction cartridges, is also called the SPE column( solid phase extraction column). The solid phase extraction column/cartridges is a pretreatment device for the sample being analyzed, which developed from the chromatographic column for extraction, separation, and concentration.

Applications of SPE cartridges

SPE cartridges are mainly used in the sample pretreatment of target compounds in farm product and livestock products, various food, environmental samples, and biological samples. SPE technology has been widely used in many industry analysis standards and national standards(GB/T).

Principles of SPE cartridge

SPE mainly comply with the separation principle of selective adsorption and selective elution by liquid chromatography. Based on the theory of liquid-solid chromatography, selective adsorption and selective elution were used to enrich, separate and purify the samples. It is a physical extraction process including a liquid phase and solid phase, which can also be approximated as a simple chromatographic process.

A more common method is to pass a liquid sample solution through an adsorbent, retaining the substance under test. Then select the appropriate strength of solvent to flush impurities, and then use a small amount of solvent to quickly elution material, so as to achieve rapid separation and concentration of the purpose of purification.

Product Highlights & Core Techniques of Vacuum Filtration

Generally, we introduce advantages of Hawach products mainly around three compositions – the pump, stainless steel multi-continuous vacuum filtration, and vacuum filter holder.

Vacuum Pump

The pump is designed specifically advanced with high working efficiency and long service life. When it is exploited into experiments, there is no medium(oil pump) and no contamination, and the gas exchange tank has inner filter materials to keep air purified. Meanwhile, it possesses an ideal vacuum degree, high air velocity and installed thermal power protector which could cut electricity once the temperature of the pump surpasses 130℃.
Besides, the setting applies to frictionless membrane motivation so that no heat is generated to avoid motor loss.

Stainless Steel Multi-continuous Vacuum Filtration

This can process multiple samples spontaneously to prevent them from polluting each other and enhance working efficiency. The stainless feature is easier to be pasteurized and resists high temperature and erosion.

Vacuum Filter Holder

The holder utilizes superior glass materials which are cleanly transparent without air bubble. In addition, it has excellent pressure resistance for the autoclave.

Get Familiar with Hawach High-Performance Extraction Thimbles

A. Cellulose Extraction Thimbles

1. 60% high purity grade polar fiber+40% refined cotton fiber no any binding agents which make it has stronger mechanical strength and stronger retention
2. 6 wall thickness optional to meet different retention and wet strength, dry strength increasing requirements or other special requirements.
3. DOP Retention 99.8%@0.3μm, Maximum temperature 100 ℃，
4. 30 sizes optional to fit for all your laboratory extractors.

B.Glass Fiber Extraction Thimbles

1. Low background response
2. Maximum temperature 600 ℃ compared to others’ 500 ℃
3. DOP Retention more than 99.99% (condition: >0.3 μm)
4. Weight loss less than 0.20%
5. 3 Sizes optional for use

Someone may ask how are we gonna choose the right size of Extraction Thimbles?

It’s indispensable to choose the appropriate size to match the normal use of the extractor. While most of the times the difference is only a few millimeters.

Remember one principle: The filter cartridge passes through the narrower end of the extractor and has a gap of 1-2 mm, and 5-10 mm above the top of the siphon. Pay more attention to the thickness while you are calculating the outside diameters.

A Brief Introduction to Hawach Qualitative Filter Papers

Qualitative filter papers usually apply to filter at atmospheric pressure, which uses the ability of the material to remove particles to separate the liquid and solid of the sample. It covers most of the laboratory applications, is used commonly for liquid clarification and, sometimes, for qualitative analysis and purification of the deposits.

In the industrial filtration, it is commonly used to separate solids or extract liquids from solution as a filter material, not as chemical analysis filter paper. The Hawach qualitative filter paper has two categories: standard grade products and wet strength grade products. Users can select from either product depending on their requirements.

Standard Grade qualitative filter papers

Standard grade qualitative filter paper is frequently used in conventional filtration. There are several models of its different particle retentions and filtration speeds.

Usually, the slow filtration speed ones which have stronger separation ability by high adsorption are suited for the chemical analysis. In industrial, medium particle retention, medium filtration Speed models are especially suits to the analysis. Besides, the fast filter paper is thicker and has a higher load which can be used for filtering culture media and colloid substances.

Product parameters

Wet Strength grade qualitative filter papers

Considering some special requirements of users, Hawach developed wet strength qualitative filter paper on the basis of standard grade products. The chemical stabilizer was added to the materials of this kind of filter paper to improve the breaking resistance significantly. However, wet strength is not recommended for Kjeldahl nitrogen determination for the nitrogen elements from the chemical stabilizer. Users can select any model to meet your specific needs.

Product parameters

C18 HPLC Columns

C18 HPLC columns are the reversed phase columns, high purity silica gel skeleton, single function high-density bonding, excellent peak shape, extremely high stability, suitable for the separation and analysis of amphoteric and acidic compounds.

Application of C18 HPLC column

1. Good separation of neutral, acidic, amphoteric and partial alkaline compounds;
2. Especially suitable for the analysis of acidic and amphoteric small molecular compounds;
3. Can be used to maintain the stability of the compound;
4. Can be used to change the separation selectivity.

The installation and use of C18 HPLC columns

Rotate the column heads at both ends of the column and connect them to the instrument according to the direction of fluid flow on the label of the column. When the column is not in use, screw on both ends of the column.

Sample and mobile phase

To avoid blockage of C18 HPLC columns, the sample and mobile phase are filtered by a filter membrane before use. The mobile phase is a mixture of the organic phase and water phase, such as methanol-water, acetonitrile-water.

It is best to install a protective column to prevent impurities and protect C18 HPLC column.

QuEChERS-Guard for Food Safety

Today, if you go to a market, you can see various fruit and vegetables on sale, even you cannot tell which season they belong to. This is all due to modern technology and planting technique. On the one hand, we are researching on genetically modified food to enlarge its advantages and avoid its disadvantages at the same time, on the other hand, we have been exploring more advanced pesticide which can not only perform as weed killer but also as chemical fertilizer with no harm to the environment.

Whether genetically modified food or pesticide, safety is always our first and foremost concern. But how to detect pesticide residue in fruits and vegetables?

No doubt QuEChERS method. With Hawach QuEChERS kit, you can achieve your experiment results quick, easy, cheap, effective, rugged, and safe.

Whether you follow AOAC 2007.01 or EN 15662, whether you want the kit or absorbent only, you can always find your ideal choice in Hawach.

All Application and Test Report strengthen our confidence in improving your experiments. If you have more questions, just feel free to contact us with info@hawach.com.

NH2 HPLC Columns

NH2 HPLC columns can be used in the positive phase or in the negative phase, but it should be noted that the positive phase solvent and the negative phase solvent are usually not mutually soluble. New NH2 HPLC columns are preserved in the positive phase environment under normal circumstances.

Preservation of NH2 HPLC column

For the reversed phase, it can be preserved with 95% methanol or acetonitrile for short term storage. Methanol should be replaced successively with isopropanol and chloroform, and finally preserved with n-ethane for long term storage.

The usage of NH2 HPLC column

1.For positive phase usage

It is not suitable to analyze the compounds containing aldehyde compounds, carbonyl compounds and reducing sugar. The mobile phase shall be completely degassed and shall not contain carbonyl compounds or peroxides. When replacing the mobile phase of NH2 HPLC columns, ensure that the new mobile phase is mutually soluble with the original column storage solution.

2.For reversed phase

The ideal PH range is 3.0-7.0. The lower the PH is the more risk of hydrolysis. If there is buffer salt in the mobile phase, use the same proportion mobile phase without buffer salt to avoid the precipitation of buffer salt.

Installation of the HPLC Column

The installation of the HPLC column should be carried out in the following three steps:

a. Unpack the HPLC column and confirm the type, size, date of manufacture, and solvent stored in the column.

b. Unscrew the sealing plug from the joints at both ends of the column and put it back in the box for spare.

c. According to the flow direction indicated on the HPLC column, connect the inlet end of the column to the outlet of the injection valve through the connecting pipe (if the conditions permit, it is recommended to use the guard column in front of the column); the outlet of the column is connected with the detector. The connecting pipe is a stainless steel pipe having an outer diameter of 1.57 mm and an inner diameter of 0.1 to 0.3 mm.

Both ends of the connecting tube have a hollow screw and a sealing ring for sealing. Always try to reduce the dead volume outside the column when taking over. After the connecting tube passes through the hollow screw and the pressure ring, insert it as far as possible into the end, then tighten the hollow screw clockwise until it stops, then use the wrench to continue to screw 1/4-1/2 turn clockwise, remember not to use too much force.

If the HPLC column is leaking after being pressurized by the mobile phase, use a wrench to continue to turn 1/4 turn clockwise until it does not leak.

Guide for Selecting Filter Membranes

Filter membranes have different types and apertures for removing bacteria and impurities, which is important to protect the chromatographic system and column.

Factors to be considered in the selection of membranes

The first thing to consider is chemical compatibility, that is, whether the filtration membrane is acid, alkali, organic solvents and so on.
1. The apertures of the filter membrane;
2. Characteristics of the filter sample.

Characteristics and applications of several common filter membranes:

1. Water system filter membrane
Uniform pore size, high porosity, no media shedding, thin texture, low resistance, fast filtration speed, low cost, but not resistant to organic solutions and strong acids and bases.

2. Nylon filter membrane
Good temperature resistance, high-pressure sterilization of saturated steam for 30 minutes, the highest working temperature 60 ℃, good chemical stability, can withstand dilute acid, dilute alkali and other organic and inorganic compounds and solvents.

3. PVDF filter membrane
High mechanical strength, good tensile strength, good heat resistance and chemical stability, low protein adsorption, strong hydrophobicity.

4. PTFE filter membrane
Wide chemical compatibility, good temperature resistance, strong acid, and alkali resistance, suitable for strong chemical corrosive solvents and oxidants.

Structure of HPLC Columns

The empty column is assembled from column joints, column tubes, and filters.

The HPLC columns joints are constructed with a low dead volume. The column joints are threaded assemblies at both ends, with 7/16-inch external threads on one end and 3/16-inch internal threads on the other end (standardized at home and abroad). The 7/16-inch external thread is connected to the 1/4-inch column tube (Φ6.35mm) and placed in the middle for sealing. The 3/16″ internal thread is connected to the 1/16″ (Φ 1.57mm) connecting tube, and a pressure ring is placed in the middle for the seal of the column joint.

In order to minimize the dead volume outside the column, when installing the HPLC columns, use a Φ1.57mm connecting tube to insert the hollow screw into the ring, and then tighten the hollow screw. The pressure ring is pressed and deformed by the hollow screw and then hung on the connecting pipe (the length of the pipe exposed after the connecting pipe passes through the pressure ring should be strictly controlled to 2.5 mm long or other fixed sizes).

In the column joints at both ends, a stainless steel filter (or strainer) is placed at each end of the HPLC column tube to block the column packing from being washed out of the column by the mobile phase. Each component of the empty column is made of 316# stainless steel, which can withstand the general solvent effect.

However, since the chloride-containing solvent is corrosive to it, it should be noted that the solvent and the connecting tube cannot be stored for a long time to avoid corrosion.

https://www.hawachpipette.com/hawach-scientific-advanced-mechanical-pipette/

Hawach Scientific mission is to work with our customers to make the world healthier, cleaner and safer. We help our customers accelerate research in the life sciences, solve complex problems and challenges in the analytical field, promote the development of medical diagnostics, accelerate the drug launch process, and improve laboratory productivity.

Hawach multi-channel advanced mechanical pipette is comfortable to use and can play an ideal role in the application of microplate. Color-coded wide finger support and ergonomic handle design can improve your fluid transfer test. The advanced mechanical pipette can be used for single and multi-pass molds. We are leading the way in introducing integrated solutions that combine innovative technologies, convenient procurement and all-around services.
More detail information from info@hawach.com.

Products specification
Single-channel Adjustable Volume
Single-channel Fixed Volume
Eight-channel Adjustable Volume
Twelve-channel Adjustable Volume

Products description
1. Ergonomic comfort
2. Color-coded wide finger-like supports are ergonomic in their identification
3. The design of the handle is soft enough to attach to the shape of your hand
4. Large Ergovisio display, easy to identify capacity

Function
1. Durable handle material
2. Double control liquid transfer button; The rotary button cap at the top prevents accidental volume selection errors.
3. Advanced gear capacity selection mechanism can enhance precision and accuracy
4. Strong blowing force to achieve 50 microns and below the efficient transfer of droplets

More Advanced Pesticide Analysis QuEChERS Solution

QuEChERS method was originally applied to extract pesticides from fruits and vegetables. Whether under AOAC or EN stipulations, according to our products’ Application and Test Report, we can see that the combination of salting out and d-SPE-purification in the initial liquid-liquid extraction has shown more satisfactory results in the multi-residue analysis of pesticides, veterinary drugs, and mycotoxins in various foods and agricultural products.

Furthermore, Hawach QuEChERS solution has presented more advantages over other pesticide analysis products and technologies:
Easy to operate, high time efficiency, stable experimental results, high-cost performance, reduce labor costs, improve work efficiency, quick start kits selections, suit for both AOAC and EN stipulations, free match those materials of all kits, can customize your unique kit etc.

Hawach offers a wide range of sorbent blends to help you remove complex matrices from your samples:
C18 can be used to remove non-polar interferences such as fat;
PSA can be used to remove polar interferences, including sugars and organic acids;
A bulk adsorbent containing graphitized carbon black (CGB) and C18 can also be supplied to remove excess fat or high levels of chlorophyll.

No more hesitations, come to contact us info@hawach.com

Diaphragm Vacuum Pumps

A diaphragm vacuum pump is mainly used in the fields of medical and pharmaceutical product analysis, fine chemicals, biochemical pharmacy, food inspection, public security criminal investigation technology, etc.

The advantages of a diaphragm vacuum pumps

1. Advanced design and technique.
2. High efficiency.
3. Long service life.
4. Does not produce pollution.
4. No working medium is required.
5. The gas exchange chamber is provided with filter material.

Applicable occasions of a diaphragm vacuum pumps

It is made of aluminum alloy die-casting, anti-corrosion spraying and plastic spraying, light and beautiful, wide application range. The air chamber adopts Teflon treatment. Therefore, a diaphragm vacuum pumps have the feature of high corrosion resistance and can meet the requirements of various working environments.

Matters needing the attention of a diaphragm vacuum pump

1. Working environment temperature cannot exceed 55 ℃.
2. This product cannot be used at high altitude.
3. It is the precision instrument. Keep away from dirt and moisture.
4. Do not allow corrosive liquids or particulate matter into the pump. Water vapor, oil contaminants or other liquids must be filtered out.

A Glance at Gravity Filtration and Vacuum Filtration

Filtration is a technique to separate a solid from a liquid by passing the mixture over a filtering media. The feature of filtering media is chemically inert to the mixture, and all kinds of media have small patch way for the liquid to pass through, while the pathways should be smaller than the solid particle size.

The mixture of solid and liquid can be forced through the filter by two ways, gravity filtration, and vacuum filtration. And each technique has its advantages.

Gravity filtration is often used for filtering larger size particles through kind of course media. It is also the best way of filtration when we use the solvent of low boiling point as the solution is hot.

The advantage for the vacuum filtration is in the condition of filtrating very small particles such as decolorizing carbon. It can force some near pore size solids through the filter media, while gravity filtration can’t. Vacuum filtration is also used to dry crystals to speed up the analysis. It is perfect if you want to save some time in the lab.

Introduction to the Structure of Standard Diaphragm Vacuum Pumps

The laboratory vacuum pump is a basic instrument that can be used with a variety of instruments and equipment. It is very versatile. With the continuous upgrading of laboratory equipment, the requirements for vacuum pumps as auxiliary instruments are also increasing.

Standard diaphragm vacuum pumps is an oil-free vacuum pump designed based on the user’s new requirements. It solves the problem that traditional pumps need to be filled with water. The pump needs to be added and replaced, and there is pollution.

The standard diaphragm vacuum pumps uses an oil-free piston structure. It does not require the addition of pump oil or water. It only needs to be plugged in to start the work.

The two-stage series pumping structure design can make it shorter. High vacuum is achieved in the time; the low-noise air-cooling heat dissipation system is installed on the side of the secondary cylinder, which greatly reduces the heat during the working of the machine, ensuring that the model can work continuously for 24 hours for a long time; Working noise, the air outlet is equipped with a silencer to reduce wind noise.

Important Technical Parameters of Cellulose Extraction Thimbles

Hawach will introduce cellulose extraction thimble from six technical parameters: material, temperature and forming time, DOP retention, size selection, porosity, and fitting accuracy.

●Material
The consistency of component content of extraction thimbles made of different materials and those made of the same material has a great influence on the determination accuracy of various detection and analysis.

Cellulose extraction thimbles consist of high-grade alpha cellulose/seamless noble cellulose and linters of cotton without any binding elements(60% high-clean poplar fiber +40% refined cotton fiber).

●Temperature and forming time
The relevant temperature parameters and forming the time of the cellulose extraction thimbles can reflect the tolerable working temperature to a certain extent and the requirements of special working conditions. Relevant parameters are as follows:
The heating temperature: 75℃;
The forming temperature: 10℃;
The forming time: 1Hour;
The maximum temperature is 100℃;

●DOP Retention
The DOP Retention is a reflex of retention ability. The DOP Retention(% @0.3) of cellulose extraction thimbles is 99.8% .

● Size selection
As shown in the figure below, ID represents the inner diameter of the filter cartridge, H represents the height of the cellulose extraction thimbles, and wall thickness reaches the thickness of single-sided thimbles.

●Porosity: Consistent high porosity ensures fast flow through.

●Fitting accuracy: High fitting accuracy for all available extraction systems.

Three Types of Bottle-top Dispensers

According to the properties of solutions, the bottle-top dispensers are divided into three types.

The first one is the basic one. It is highly applied to the common solutions, such as the non-oxidative but a strong acid/base with a lower concentration, polar organic solvent and the solutions of acid, alkali or salt. H3PO4, HCL, H2SO4, NaOH are frequent here.

The second one is the organic one. It is used for the vast majority of organic solutions and the strong acid with high concentration. Let me list some examples. There are the organic solvents containing fluorine or chlorine, chloroform, peroxide, and some other solvents.

The third one is applicable to HF solutions. The plunger of the bottle-top dispenser is made of pottery and porcelain because HF solution can corrode glass.

The process of moving solutions by the bottle-top dispenser is totally closed, which effectively prevent the solvents’ volatilization, spatter and spill. That is safer than moving solutions by cylinders. We can even transfer the solvents with high density and volatilization in the petrochemical industry.

What’s more, chloroform is usually used as solvents for most plastics. It is often used for experiments in labs. However, it is easy to volatilize and poisonous. Transferring chloroform through the bottle-top dispenser can avoid it because of the closed conditions.

Why do We Recommend Bottle-Top Dispensers?

If you want to dispense an aliquot of liquid from bottles, the bottle-top dispensers always provide the best results for your lab in the way of productively dispensing and no reagent wasting.

Depending on what you need, the important factors of choosing the bottle-top dispenser include the volumes and the type of the liquids you will dispense such as strong acids and bases, organic solvents, saline solutions, etc.

You always need to make sure that your liquid handling settlement is properly calibrated, and up to a high standard every single time. Calibrating bottle top dispenser is an important step to guarantee your liquids dispense is precise and accurate in the lab. Scientists prefer to use a pipette correctly calibrated, the situation is the same when dispensing liquids using bottle top dispensers. Be aware of checking out the bottle-top dispenser calibration all the time.

Combined with perfect calibrating equipment, the good quality bottle-top dispensers will be achieving the best results, saving your lab money with no more reagent loss, and avoiding the annoying repeated experiments and extra working hours in the lab.

Hawach’s Bottle-Top Dispensers Introduction

Hawach has two types of the bottle-top dispenser, the electronic one and the mechanical one. They are made of excellent chemical resistance and the components are made of PTFE, FEP, BSG, PP. It is available for fully autoclavable at 121℃.

The electronic bottle-top dispensers, the volume range is from 0.1ml to 99.9ml. The max piston lift is 10 ml and resolution is 100ul. The electronic control decreases the repetitive strain injury. In addition, the remote control panel makes the operating process without the manual disturbance.

The mechanical bottle-top dispensers have four range covering a volume range from 0.5ml to 50ml. They are easy for operation, cleaning and maintenance following the user’s manual.

Based on the optional flexible discharge tube, our bottle-top dispenser presents the performance of fast and precise dispensing. We also offer the full-size adaptors with S40, GL32, GL38, GL25, GL28. The structure as:

At present, the bottle-top dispenser has a wide application, such as biological, Pharmaceutical, Clinical, Chemical, Forensic laboratories, etc. If you are interested in our bottle-top dispenser, welcome to have the request of quotation. The E-mail available: info@hawach.com.

Filter Paper

Hawach Scientific work for filter paper for more than 16 years, we are happy to see our products exported to the United States, UK, Germany, Dubai, Thailand, South Korea, and other countries.

We are not satisfied with our present achievement, this year our R&D department have good news: We have a new type of filter paper special for wine filtration, the specifications just as followings:

1. All of our filter papers all manufactured from High-quality cotton liners to ensuring quality;
2. Particle Retention: 7-10um;
3. Filtration Speed: Medium;
4. Basis Weight: 80g/m2;
5. Grade: Food grade;
6. 20*20cm, 40*40cm are regular size, if you need other sizes, we can customize for you.

Here is the photo of our filter papers:

If any question about the filter paper, please don’t hesitate to contact us!
Thank you for your time!

Overview of SPE Technique

SPE Technique Introduction

SPE(Solid-phase Extraction), is an increasingly popularized technology of sample pretreatment, which is established on the basis of traditional LLE(Liquid-liquid Extraction). Combined with the substance interaction mechanism that like dissolves like, and basic knowledge of stationary phases with currently widely applied HPLC(High-Performance Liquid Chromatography) and GC(Gas Chromatography), the skill has been gradually developed.
Besides, SPE features a small number of organic solvents, convenience, safety, and high efficiency.

SPE Technique Category

According to the similar dissolution mechanism, SPE can be divided into four types– reverse SPE, positive SPE, ion exchange SPE, and adsorption SPE.

SPE Technique General Applications

SPEs are mostly utilized to treat liquid samples extracting, concentrating and purifying the semi-volatile and non-volatile compounds. If solid samples are provided, they have to be processed into liquids ahead. Nowadays, domestic applications mainly focus on the analysis of polycyclic aromatic hydrocarbons(PAHs) and polychlorinated biphenyls(PCBs) for watery conditions, pesticide and herbicide residues in fruits, vegetables and food, antibiotic analysis and clinical drug analysis.

SPE Technique Typical Applications

● Biological fluid analysis
● Analysis and monitoring of drinking water, groundwater, and sewage
● Volatile oils, plant tissues, fruits, vegetables, and grains
● Liquid drug samples, soils, and sediments
● Meat, fish and other animal tissues
● Tablets and other solid drugs

Vacuum Filtrations

Vacuum filtrations are based on the principle that oil and water vaporization temperature is different (water vaporization temperature is lower than oil vaporization temperature) under the same pressure.

Vacuum filtrations are a kind of paper filter equipment with the features of a high degree of automation and high precision, filter precision up to 10 microns.

Application of vacuum filtration – a vacuum oil filter

It relates to a continuous filtration operation for dewatering sludge, which is generally completed in a cylindrical rotary filter. The filter media can be natural fabric, synthetic fiber products or wire mesh. Usually, in order to make the vacuum oil filter to achieve good processing capacity, it is necessary to adjust the wet sludge.

Matters needing the attention of vacuum filtration

Before any maintenance or overhaul of the vacuum filtrations system, the pressure in the system must be released and the power cut off! High pressure can lead to heavy casualties!

When vacuum filtration system is working, it is not allowed to be close to or step on the scraper, or enter the box, which is controlled by the program time and may start suddenly, if involved, it may seriously damage personal safety.

Glass Fiber Membrane Filters

The glass fiber filter is chemically inert and contains no binder. It is made of 100% borosilicate glass fiber. It has a capillary structure, can absorb more water than the same cellulose filter paper, has the characteristics of fast flow rate, high-temperature resistance and strong dirt holding capacity, and can filter fine particles. But in our company, we have two types of with binder and without binder. So when you going to buy it, you should know the type you need. As an important part of FRP products, glass fiber is widely used, and the application of filter film is very close to our daily life. The glass fiber membrane filters are extremely fine fiber, which has high filterability and high dirt carrying capacity and has good hydrophobicity and biological inertness.

Compared with other fiber materials and synthetic materials, glass fiber membrane filters have higher filtration efficiency and belong to deep filtration. Their main purpose is to use as a filter layer and directly on the membrane filter. Glass fiber membrane filters are used for routine monitoring of air pollution monitoring and special monitoring of solid contaminants, microorganisms, oils and acid mist in the air. It is used for the collection of highly efficient fine particles for water pollution analysis. It is an ideal product for collecting dust in the air and accurately measuring it. It can be used for pre-filtration of membranes to prevent clogging of membranes; large surface area uses glass fiber membranes for excellent retention. Different sizes of filters have specific requirements on the diameter of the pre-filtration membrane. Learn more about the different specifications of adhesive-free glass fiber filters:

MG A high-efficiency filtration is generally used for laboratory solvent buffer purification, air, and water pollution testing, in line with international standards
MG B filters and screens suspensions in water, sewage analysis, prefilters, suitable for bulk filtration.
MG C standard for wastewater and rainwater purification testing filters, cell collection, and hydrocarbon analysis.
MG D is generally used for pre-filtration.
MG F Efficient microparticle collection filter, protein purification for high-performance liquid chromatography liquid filtration.
MG G water filtration and testing.

Introduction of Hawach Microporous Membrane Products

The microporous membrane is one of the most widely used membrane types in membrane separation technology. It has the characteristics of large gas flux, high particle retention rate, good temperature resistance, strong acid, strong alkali, organic solvent and oxidant, anti-aging and non-stick, non-flammable and non-toxic, and good biocompatibility. Its material can be divided into organic and inorganic categories.

In view of the separation characteristics of the microporous filter membrane, the application scope of the microporous filter membrane is mainly to trap particles, bacteria and other pollutants in the gas phase and liquid phase to achieve the purpose of purification, separation, and concentration.

For microfiltration, the membrane interception characteristics are characterized by the pore size, usually ranging from 0.1 microns to 1 micron, It can be used for clarification, security filtration and air sterilization of general liquid. It is widely used in scientific research, medicine and health, biochemistry, food, energy, microelectronics industry, nanotechnology, environmental protection, and other departments.

Microporous membrane application

This product is mainly used for the filtration of the mobile phase and sample in chromatographic analysis. It has a good effect on protecting the chromatographic column, infusion pump pipe system and injection valve from contamination.

Microporous membrane material

1. MCE gridded membrane filter
2. Nylon membrane filter
3. PTFE membrane filter
4. PES membrane filter
5. CA membrane filter
6. PVDF membrane filter
7. GF membrane filter
8. PP membrane filter

Guide for Selecting Filter Membranes

Filter membranes have different types and apertures for removing bacteria and impurities, which is important to protect the chromatographic system and column.

Factors to be considered in the selection of membranes

The first thing to consider is chemical compatibility, that is, whether the filtration membrane is acid, alkali, organic solvents and so on.
1. The apertures of the filter membrane;
2. Characteristics of the filter sample.

Characteristics and applications of several common filter membranes:

1. Water system filter membrane
Uniform pore size, high porosity, no media shedding, thin texture, low resistance, fast filtration speed, low cost, but not resistant to organic solutions and strong acids and bases.

2. Nylon filter membrane
Good temperature resistance, high-pressure sterilization of saturated steam for 30 minutes, the highest working temperature 60 ℃, good chemical stability, can withstand dilute acid, dilute alkali and other organic and inorganic compounds and solvents.

3. PVDF filter membrane
High mechanical strength, good tensile strength, good heat resistance and chemical stability, low protein adsorption, strong hydrophobicity.

4. PTFE filter membrane
Wide chemical compatibility, good temperature resistance, strong acid, and alkali resistance, suitable for strong chemical corrosive solvents and oxidants.

Laboratory HPLC Columns

HPLC columns are manufactured and tested to exacting standards. If you use and maintain a liquid chromatography column with the following information, you will not only get better results but also extend the life of your HPLC column.

Installation of HPLC columns:
1. First, check that the column and instrument connections and piping are matched. In order to reduce the dead volume, the inner diameter of the connecting pipe between the injection valve, the column, and the detector should be as small as possible, and the length of the connecting line between the injector, the HPLC column, and the detector should be controlled. Before installing the LC column, verify that the solvent in the flow path system is normal. It is recommended to install a guard column for more complex samples.

2. In order to achieve the best connection between the HPLC column and the instrument system, the nut and tapered joint matching the LC column interface should be used as much as possible. For example, the original joint is long-term matched with other types of LC columns. Check the match before connecting the new HPLC columns to avoid damage to the HPLC column or leakage due to the mismatch in the HPLC column.

3. the use of PEEK material universal joints, only need to hand tighten without the need for a specific wrench, the use of pressure is 5000psi; the use temperature must not exceed 100 °C.

Advantages of QuEChERS

Hawach summarized the advantages of QuEChERS in eight aspects.

1. Recovery Rate

QuEChERS technology has the advantage of high recovery rate. Experimental data show that the recovery rate of large quantities of polar and volatile pesticides by QuEChERS is above 85%.

2. Accuracy

Laboratory workers can make use of the internal standard method to maintain correction with high accuracy in QuEChERS technology.

3. Analytical Range

The analytical range of pesticides by QuEChERS technology is wide. Pesticides including polar and nonpolar both can get great recovery rates by taking this technology.

4. Analysis Speed

The analysis speed of QuEChERS technology is fast that laboratory workers can deal with 6 samples within 30 minutes.

5. Use of Solvent

With less use of a solvent (0% use of a chlorinated solvent), QuEChERS technology can bring less pollution and lower cost in comparison with traditional techniques.

6. Operation

Easy operation of QuEChERS technology makes laboratory workers performing analysis quite smoothly without being well trained to have a command of advanced skills.

7. Safety

The container will be sealed immediately after acetonitrile is added inside, which reduces exposure between laboratory workers and the hazardous substances.

8. Sample Preparation

During the process of sample preparation in QuEChERS technology, less glassware is used and the whole equipment is simple and convenient for laboratory workers to conduct experiments and perform analyses.

A brief description of QuEChERS

QuEChERS is a pretreatment that has the characteristics of Quick、Easy、Cheap、Effective、Rugged and Safe, which is the reason why it is becoming more and more popular in the new testing methods. It was developed by Professor Anastassiades in 2003, which was used in agricultural testing at first.

The principle of QuEChERS is similar with the HPLC and SPE. QuEChERS purifies the substance because the interaction between the adsorptive stuff and the impurities of substrates can help absorb the impurities. Detailedly, after the homogenized samples are extracted by acetonitrile and the salting-out method, the disrupters of the samples combined with the PSA or some other adsorptions, such as organic acid and aliphatic acid. And then the impurities are removed by centrifugation. Therefore, the quality determines the test results.

QuEChERS is widely used in many fields as a testing method, especially in Pesticide Residues Determinations. We can use it to purify substances in numerous field as long as the percent recovery of the samples is in the allowable ranges and the substrates fit the needs of testing.

QuEChERS Product Related Information

The definition of QuEChERS and Product Information

QuEChERS means Quick, Easy, Cheap, Effective, Rugged and Safe, which is a sample preparation method and applied for the detection of Agricultural Products widely. Hawach has a great diversity of QuEChERS products for your choice, including the Extraction kit, the Extraction salt, Dispersive SPE Kit, Dispersive Absorbent, Ceramic Homogenizers.

Workflow

Firstly, you should select the test method, such as AOAC or EN, and prepare the buffered Extraction Kit & 50ml tube. Put the 10g or 15g comminuted sample into the tube and add the acetonitrile & extraction salt. After shaking the tube with 1 min, add the internal standard into the tube and do the centrifuge. Extracting the supernatant solution of 1ml, 6ml or 8ml and transferring it into dispersive SPE kit. In the same way, after shaking the tube with 1min, to do the centrifuge and Aliquoting the supernatant solution. Take it to be ready for analysis with GC-MS or LS-MS. Finally, achieve the analysis report. The whole of the process just takes about 30 minutes, which is a very convenient and fast operation.

If you are interested in Hawach QuEChERS products, welcome to have the request of quotation. The E-mail available: info@hawach.com.