hawachscientific (hawachsci)
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Three Cleaning Methods of Sample Vials
Sample vials play an important role in the experiments. We’d better not reuse them. If it has to be reused, the cleaning method is very important. It is noteworthy that vial pads must be replaced with new ones. Otherwise, the quantitative results will be affected. And here we will introduce three cleaning methods. Method one 1. Soak the vials into the methanol, and at the same time wash it with ultrasound for 20 minutes. After that, pour out the methanol. 2. Fill the vials with water, and wash it with ultrasound for 20 minutes. After that, pour out the water. 3. Dry the vials. Method two 1. Soak the vials in the medical alcohol for more than 4 hours, and then wash it by ultrasound for half an hour. Pour out the water. 2. Soak the vials in the water and wash it by ultrasound for half an hour. 3. Dry it. Method three 1. The vials should be soaked in a potassium dichromate solution for 24 hours. 2. Be cleaned three times with deionized water under the condition of ultrasound. 3. Be cleaned with methanol once. 4. Dry it.
about 5 months ago from web -
Brief Introduction to Flash Column Chromatography
Flash column chromatography can overcome the defect of ordinary column’s separation. It has the advantages of quick, time saving, high efficiency of separation, simple and practicable. As for samples of 0.01 to 10 grams and the Rf value more than 0.15, they can be quickly separated within 10 to 15 minutes. Packing 1. The adsorbed stationary phases are normally silica gel and aluminum oxide. The required mesh numbers are 100 to 160 or above 160, 2. The lower of adsorbing agent’s mesh number is, the higher degree of separation will be. However, the elution rate will be relatively slower, 3. When there are great differences between the Rf values, you can load 30 mg/g of silica gel with a mesh number of 100 to 160. In more cases, 10 mg/g of silica gel is required, 4. When using aluminum oxide, the required mesh number is 100 to 150. 20 to 50 grams of aluminum oxide are needed to separate 1 gram of sample. Conditions and Procedures of Flash Column Chromatography 1. Choose the eluting agent with high separation efficiency on TLC board, 2. Choose an appropriate chromatographic column with silica gel with a mesh number of 230 to 400, 3. After the eluting agent is added, quickly eliminate the air inside the silica gel under the pressure, 4. After sample loading, elute and control the flow rate within 2.0 in/min.
about 5 months ago from web -
The Difference Between Gravity and Vacuum Filtration
As a technique widely used in the lab, the filtration is the best way to remove solid impurities from an organic solution and to isolate an organic solid. We can find two types of filtration: gravity filtration and vacuum filtration. Gravity filtration is a common method to remove solid impurities from an organic liquid. The impurity that we call in the applications could be a drying agent, an undesired side product or leftover reactant. Vacuum filtration is used to collect a desired solid too. But compare with gravity filtration, it is much faster in the result of the solvent and air being forced through the filter paper by the application of reduced pressure. Remember, never use vacuum filtration to filter a solid from a liquid if you want to use the liquid, and the solvent boiling at about 125 degrees or lower will boil off in the vacuum flask while the pressure is reduced.
about 5 months ago from web -
Experimental Steps and Advantages of QuEChERS
QuEChERS is a sample pretreatment technique for sample preparation and purification of multi-pesticide residues in foods with high humidity. At present, QuEChERS is more and more widely used, involving more and more fields, such as drugs, antibiotics in soil, wine, meat and other pollutants detection. Steps of QuEChERS 1. Sample crushing; 2. Single solvent acetonitrile extraction and separation; 3. Add salt to remove water; 4. Adding adsorbent; 5. Perform GC-MS and LC-MS detection. Advantages of QuEChERS 1. Simple device and simple operation; 2. Acetonitrile has little contact with the staff; 3. Chlorine-free solvent; 4. Low pollution, low cost, high accuracy; 5. Rapid analysis; 6. Both polar and non-polar types of pesticides can achieve a good recovery rate. QuEChERS technology invented just a few years ago, has brought innovation to the field of multi-pesticide residue analysis and multi-category pesticide analysis. Now, in order to meet the demand for food production, a variety of pesticides have been used. Therefore, more attention has been paid to the residue analysis method of multiple pesticides, especially after the frequent occurrence of pollution events in our food supply.
about 5 months ago from web -
Extraction Thimble In Soxhlet Extraction
Notably, the extraction thimble has a special and common application to the Soxhlet extraction experiment. About Soxhlet Extraction The classical Soxhlet extraction has a history of more than 100 years, which is also an effective way of extraction and usually serves as a reference standard for new extraction methods. Specific Usage Progress To improve extraction efficiency, save time and reduce manual operation, there has been the automatic Soxhlet extractor for extracting multiple samples simultaneously. Both the extraction time and temperature are required to be precisely controlled electronically, which makes the entire operation more automated. Actually, automatic Soxhlet extraction is a combination of thermal solvent extraction and regular soxhlet extraction. Automated Soxhlet extraction (ASE) needs the sample in the extraction thimble to temporarily remain in boiling solvents. When a certain given time arrives, the thimble would automatically ascend to the upper part of the solvent, and then goes through the condensation solvent circulation. The process is almost the same as classical soxhlet extraction except for characteristics of the shorter extraction time and a higher degree of automation.
about 5 months ago from web -
Distinction and Relationship of Different Filter Papers
Three Types of Filter Paper Currently, there are mainly three kinds of filter paper: quantitative analysis filter paper, qualitative analysis filter paper and chromatography qualitative analysis filter paper. 1 Quantitative Analysis Filter Paper In the manufacturing process, reacting with hydrochloric acid, hydrofluoric acid treatment and distilled water washing, most of the impurities of paper fiber will be removed. So after burning, few residual ashes exists, which has little impact on analysis results. 2 Qualitative Analysis Filter Paper This one actually has comparatively more residual ash, which only serves for general qualitative analysis and filtering the precipitation or suspension in solutions, but for quality analysis. 3 Chromatography Qualitative Analysis Filter Paper Its major role is the support of paper chromatography. Comparison Qualitative filter paper is applied to solution filtering, while quantitative filter paper is designed for filtration based on precise calculation numerical value. And treatment in high-temperature furnace is required after the filtering of quantitative filter paper. Besides, concepts of quantitative filter paper and qualitative filter paper appear because of the cellulose filter paper, so they can not be adapted to other filter paper types like glass microfiber filter paper.
about 5 months ago from web -
Chromatographic Classification Method
There are many types of chromatographic methods, and different classification methods can be used from different perspectives. Classification from the state of two phases. In the chromatography, the mobile phase may be a gas or a liquid, and thus can be classified into gas chromatography (GC) and liquid chromatography (LC). The stationary phase can be either a solid or a liquid coated on a solid, thereby separating gas chromatography and liquid chromatography into gas-liquid chromatography, gas-solid chromatography, liquid-solid chromatography, liquid-liquid chromatography. Chromatography The earliest application of chromatography was to separate plant pigments by placing calcium carbonate in a glass tube and pouring petroleum ether containing plant pigments (plant leaf extract) into the tube. At this point, a mixed band of several colors appears immediately at the upper end of the glass tube. Then rinse with pure petroleum ether. With the addition of petroleum ether, the band will continuously move downwards and gradually divide into bands of several different colors. After further washing, the pigments of various colors can be respectively obtained, and respectively Identification. Chromatography is also named after this. The current chromatography method has long been not limited to the separation of pigments, and its method has been greatly developed, but the principle of separation is still the same. We still call it chromatographic analysis.
about 5 months ago from web -
How the Samples Affect the Life of Liquid Chromatographic Column
One of the main factors affecting the life of the liquid chromatographic column is the samples. The first reason is the solubility of samples. When the experimenters preparing makes the sample samples, maybe there will be a small amount of particles that are completely dissolved. The small amount of particles will be brought into the chromatographic columns with the samples. And thus the particles build up in the head of the columns, which causes the blockage of the column under normal conditions. The second reason is the purity of the samples. The samples that will be used in the chromatography include not only the components to be analyzed but also other various components or impurities. These components or impurities may not be adsorbed irreversibly in the columns, which covers the active point of the stationary phase. The retention characteristics are changed. The third reason is the chemical properties of samples. There should exist chemical stability between the various components of the samples to be analyzed and the fillers in the columns. Typically, to remain the stability in the progress, when using amino-bonded columns, compounds and mobile phases with carbonyl should be avoided using. For instance, acetone or ethyl acetate cause the condensation of NH2 with anhydride and Schiff, which will destruct the stationary phases.
about 5 months ago from web -
Sterilization Method for Syringe Filter
Sterile syringe filters are mainly used in the pharmaceutical industry, fermentation, food & beverage, beer brewing, biological products and others. How to sterilize the syringe filter? Generally, Hawach has two methods, ETO sterilization and Gamma sterilization. The following is some description: ETO sterilization, namely ethylene oxide sterilization. It destroys the metabolism of bacteria, causes microbial death, and achieves the purpose of sterilization. EO gas is toxic, so the concentration of EO in indoor air must be controlled to be lower than the national standard. The whole process of sterilization takes a long time, which is due to the need for long ventilation to remove EO residues. EO gas is flammable and explosive. It cannot be leaked during storage and sterilization. Safe sterilizers must be selected for safe operation and storage. Gamma sterilization is by gamma-ray irradiation, the chemical substances (DNA) in microorganisms have changed, resulting in the loss of cell activity, so as to achieve the purpose of sterilization. Gamma sterilization has the advantages of complete sterilization, non-toxicity, no residue, green environmental protection, low energy consumption and energy saving. It can sterilize a large number of products, immediately using after sterilization without waiting. Gamma-ray sterilization requires a certain device to be able to carry out, but also a one-time investment of more capital. After sterilization, the white syringe filter is probability yellowish slightly. Generally, Hawach syringe filters use Gama sterilization, which requires a certain amount for sterilization, otherwise, additional operating costs will be required; if ETO sterilization is applied, there is no need for quantitative requirements.
about 5 months ago from web -
Introduction of Laboratory and Industrial Filter Membranes
The filtration of filter membranes is solid-liquid separation technology, no chemical change, simple processing. There is no need for flocculation chemical treatment or evaporative separation when using the filter membranes device. It only needs the pressure to separate solid and liquid in water, which is a major feature of filter membrane treatment. The material of the lab filter membranes 1. Glass fiber; 2. Nylon; 3. MCE 4. PVDF 5. PTFE 6. Cellulose acetate 7. PP. Water treatment membrane filtration method 1. The liquid passes through the membrane hole vertically to retain impurities in the liquid; 2. The flow direction of the liquid is equal to the membrane surface, forming a cross-flow filtration mode in which the liquid and the membrane surface pass through the membrane holes at right angles and impurities in the liquid are trapped. In addition to being used for water treatment, filtration membranes can also be used for ultra-pure water manufacturing and seawater desalination, generally using reverse osmosis membrane. In addition, it is used for the treatment of feces and urine, urban waterways, and various wastewater, etc., generally using ultrafiltration membrane and microfiltration membrane.
about 5 months ago from web -
Filter Membranes
Filter Membranes we have two types: round disc membrane filters and roll type membrane filter, both of them can be used for filtration and sterilization of liquids, gas, and other samples. Filter Membranes remove all micro-organisms and particles reliably, without any effects on the ingredients during the whole process. We are available in a broad range of pore size and materials such as PTFE, PVDF, Nylon, MCE, CA, PES, GF, PP and etc. OEM service and customized size are also available.
about 5 months ago from web -
Flash Columns
Flash Column is a general consumable for flash chromatography method analysis, the flash chromatographic method commonly is used for isolation of a single chemical compound from mixed samples. Hawach Scientific special produced high purity stationary phased packed flash column with the full range of size supplied to global users. The column cartridge made from medical grade virgin PP material and PE frits. Column available in prepacked and empty flash column(solid sample load cartridge). Hawach Scientific offers excellent separation performance flash columns for compounds analysis of a varies of properties from hydrophilic to hydrophobic: polar, semi-polar and non-polar compounds. The stationary phase available in Standard Silica gel, Superior Silica gel, Spherical C18, Irregular C18, Spherical NH2, Spherical C4, Spherical C8, Spherical CN, Spherical HILIC, Neutral Alumina, Spherical Phenyl, Spherical SAX, Spherical SCX, Spherical C8, Spherical Diol etc.
about 5 months ago from web -
Qualitative Filter Papers
Hawach Scientific Co., Ltd is a professional manufacturer Lab Consumable, filter paper is our hot-sale products. all of our filter paper is made from pure cotton linters and the ash content of it mainly less than 0.006%, all the filter paper is produced under tightly controlled manufacturing conditions to assure the quality year after year. Two kinds can be chosen: standard qualitative filter papers and wet-strengthened qualitative filter papers. You may base on the application, filtration speed to find the most suitable products. Hawach scientific is the solution provider, professional manufacturer and your faithful friend. We also passed the ISO9001 & CE certificate. We insist on customer first, only based on service, we can go further.
about 5 months ago from web -
Flash Reversed-Phase Column
Reversed-Phase Principle The reversed-phase filler is a kindly of nonpolar filler such as C4, C8, C18 aliphatic chain which is bonded on the silica gel. Nonpolar or hydrophobic compounds are strongly reserved, while polar samples are weakly reserved and go through the flash reversed-phase column faster. The chromatographic process of “reversed-phase” is just the opposite of normal-phase chromatography. The Selection of Mobile Phase Commonly we use water and acetonitrile or water and methyl alcohol as mobile phase, and occasionally we also use water and butylene oxide. We normally will add some weak acid or weak base into the aqueous phase to turn the whole system into acidic or alkaline. This will make sure that the component can reach the peak. The weak acid or weak base we normally use is methanoic acids, trifluoroacetic acid, ammonium hydroxide, ammonium hydrogen carbonate, etc. The percentage is always the same as the liquid system. The Load of Reversed-Phase Samples Commonly we use liquid-phase for wet loading of reversed-phase samples. The solvent we normally use is water, methyl alcohol, butylene oxide, methyl cyanide, NN- dimethylformamide, dimethyl sulfoxide, etc. It is better to choose the most suitable solvent to dissolve, and 100 ml of solvent are best for 100 mg of samples.
about 5 months ago from web -
Different Tops and Bottles of Sample Vials
Vial Top Type 1. Screw Thread Top Screw thread top possesses of passing ability and excellent sealing effect. It sticks the septum throughout a mechanical way and no other tools are needed. 2. Crimp Top The aluminum crimp has a good sealing effect and can prevent sample from evaporation. When in the high-temperature experimental environment, crimp top is with higher temperature resistance. Furthermore, crimp top needs to be matched up with the crimper when used. 3. Snap Top The sealing effect of the snap top is not as good as screw thread top and crimp top. The push-type snap top is suitable for the storage of powder sample and not suitable for the transportation of liquid. Moreover, what should be paid attention to is that if the snap top’s degree of adaptability is very high, it will be hard to close and may easily be broken. On the contrary, if the snap top is too loose, the sealing effect will become worse. Glass Vial 1. Glass Glass sample vial is a kind of general type and acid proof type of vial. 2. Brown Bottle Brown bottle is suitable for the light-sensitive sample. 3. Polypropylene Septa Polypropylene bottle is suitable for alcohol sample or water-soluble solvent.
about 5 months ago from web -
Choice of Sample vials
Sample vials and its accessories are relatively mature and simple. The quality assurance of the sample vials, cap and septa provided by Hawach can meet customers’ requirements and avoid customers’ doubts on their quality. Key points to customer choice In contrast, the common applicability of vials, cap and septa used for HPLC, GC automatic sampler is the key to customer choice. All the vials, cap and septa provided by the company are manufactured in accordance with international standards, and there is no adaptation problem, which can ensure the repeatability of the results. Naming rules of vials ●Screw：SVS201C-SampleVial+Screw top+2ml+ No writing +9mm caliber +Clear vial ●Clamp: SVC201C-SampleVial+Crimp top+2ml+ No writing +11mm caliber +Clear vial ●Snap: SSVN211C- SampleVial + Snap top +2ml+11mm caliber +clear Naming rules of cap stepa ●SLSSC002SP:STARLAB Sample vial screw cap, 002-9mm, SP-pre/slit ●SLSNC001SP: STARLAB Sample vial snap cap, 001-8mm, SP-pre/slit ●SLSSC003SP: STARLAB Sample vial crimp cap, 003-11mm, SP-pre/slit
about 5 months ago from web -
Some Commonly Used Filter Housings
A filter housing should have some advantages, such as high filtering accuracy, high speed, small absorbing amount, no media falling, no dead angle, no leakage, acid and alkali resistance, corrosion resistance, easy to clean and recoil function. Different kinds of filter housing: Stainless steel liquid filter housing (BJQ): Different filter membranes can be assembled as required. In line with GMP requirements of food and drug industry, it is ideal filtration equipment for food and drug industry. Stainless steel bag filter housing (BJD): Sandblasting, grinding and polishing internal and external; easy placement of filter bag; easy to degassing and clean. Different filter bags can be assembled. Titanium filter housing (BJTI): It is designed to decarburization filtration for pharmaceutical industry. Fluorine-lined stainless steel filter housing (BJF): Also known as breathing apparatus, it is specially produced for removing impurities and bacteria for material tank, reactor, storage tank and other equipment in the pharmaceutical, food and beverage, water treatment and other industries. Nowadays, there are more and more filter housings researched and developed for different requirements. The above are only some of the commonly used.
about 5 months ago from web -
Application of Filter Membrane in the Drinking Water Industry
The filter membranes are widely used in the drinking water industry. Its advantages are as follows: 1. No coagulant is required; 2. Simple automatic operation and easy unmanned management; 3. The water plant occupies less land; 4. Low maintenance and management costs; 5. Easy drainage; 6. It can remove suspended matter and solid matter in industrial sewage. The service life of filter membranes The membrane hole is blocked by impurities in the water, which increases the loss of water head and reduces the flow rate when the fluid passes through the membrane hole. At this time filter membranes can usually be rinsed with water so that the membrane hole to restore the original infiltration capacity. The selection of filter membranes is the key to achieve the best filtration effect. The filter material should adapt to the different chemical properties of the filter medium. At present, fluoroethylene membrane and the mixed fiber resin membrane are commonly used. Features of filter membranes 1. Strong and permanent hydrophilicity; 2. High velocity; 3. High filtration accuracy; 4. Clean, no shedding, low solubility; 5. Long service life; 6. Chemical resistance, high-temperature resistance.
about 5 months ago from web -
1. Pretreatment solvent and parameter selection We will determine the solvent and its amount and flow rate for pre-treatment and balancing of the SPE cartridge. For a reverse phase cartridge or an ion exchange column, methanol or a polar organic solvent c
1. Pretreatment solvent and parameter selection We will determine the solvent and its amount and flow rate for pre-treatment and balancing of the SPE cartridge. For a reverse phase cartridge or an ion exchange column, methanol or a polar organic solvent can usually be used as a cartridge pretreatment solution, and water or a buffer solution is used as an equilibrium solution. The pretreatment of the normal phase cartridge is usually carried out using an elution solvent or a non-polar organic solvent. The flow rate requirements for pretreatment and equilibration of the solution through the cartridge are not critical, as long as the carbon chain of the functional group is effectively extended, and the filler reaches the equilibrium state of the sample. 2. Selection of sample flow rate through the column The next step is to determine the sample flow rate through the SPE cartridge. The flow rate of the sample through the cartridge is related to the size and size distribution of the particles in the SPE cartridge, the packing density of the filler, the degree of binding of the target compound to the sample matrix, and the viscosity of the sample. For a reverse phase silica gel cartridge with 100 mg of packing, the flow rate is generally controlled at 2 to 10 mL/min. For the extraction by ion exchange mechanism, since the energy required for the interaction is larger than the non-polar force, the speed of the sample passing through the SPE cartridge should be appropriately reduced to ensure that the target compound has sufficient time and SPE cartridge packing. The ion exchange functional group acts, generally controlled at 1.5 to 5 mL/min.
about 5 months ago from web -
Correct Operation and Skill of Pipette
Some correct operation and skill of pipettes should be paid attention to by users, such as set capacity, proper operation of suction and draining operation. The suction of a pipette 1. Connect the suction nozzle properly; 2. Press the control button to the suitable gear; 3. Put the nozzle vertically into the 1-6mm below the liquid level; 4. Slowly slide the control button back to the original position; 5. Wait for 1-3 seconds before the pipette removes the liquid 6. Slowly remove the nozzle to ensure there is no liquid on the outer wall of the nozzle. Draining operation of a pipette 1. The nozzle is held against the inner wall of the capacity at an angle; 2. Slowly press the control button to the suitable gear and wait for about 1-3 seconds; 3. The nozzle will drain the remaining liquid in the process of pressing the control button to the second gear; 4. Slow down the control button; 5. Press the ejection button to eject the nozzle. When using a pipette, the forward transfer is suitable for the solution with low density. Reverse transfer is suitable for viscous or volatile liquids.
about 5 months ago from web
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