A Brief Introduction To The Extraction Thimble

Extraction thimble is an instrument for extracting nonvolatile substances from solids with a volatile solvent. It consists of three parts: reflux condenser, extractor body (with filter paper sleeve), and flask for solvent. The extracted sample is placed in a filter tube, and the solvent is heated. The steam rises from the side tube and drops into the sample through the reflux condensate tube. In this way, a relatively small amount of solvent can be used to achieve the purpose of complete extraction. Often used for fat extraction.

Use
One method of extracting compounds from solid substances is to leach the desired substances by soaking the solids in a solvent for a long period of time. The solvent dosage is large, the efficiency is not high. The extractor used in the laboratory is to use the principle of solvent reflux and siphon so that the solid material is continuously extracted by pure solvent, which not only saves solvent but also increases extraction efficiency.

The solids are ground up before extraction to increase the area of solid-liquid contact. Then the solid substance is placed in the filter paper cover and placed in the extractor. The extractor is connected to a round bottom flask with a solvent at the bottom spoon and connected to a reflux condenser tube. Heat the flask, the solvent boiling, steam rising through the extractor pipeline, after condensation drops into the extractor solvent for extraction, and solid contact when four of the top solvent than the siphon, contains extract solvent siphoned back into the flask, and therefore part extracted substances, repeat, the solid material continuously to pure by solvent extraction, extracted substance concentration in a flask.

Liquid – solid extraction is the use of a solvent mixture of solid solubility of the ingredients in big, less solubility of the impurity to achieve the purpose of the extraction and separation. One way is to put the solid material in the solvent medium and long-term immersion and reach the purpose of extraction, but this method a long time, consumption of solvent, the extraction efficiency is not high also. Another is the method of soxhlet extractor, it is using the solvent backflow and siphon principle, for continuous extraction of solid mixture components needed.

When the extraction tube under the reflux solvent in the liquid level exceeds the siphon of the soxhlet extractor, extraction solvent flow in the tube back to the round bottom flask, namely siphon. With the temperature increases, at the beginning of reflux again, before each siphon, the solid substance can be extracted by the pure hot solvent, the solvent is repeatedly used to shorten the extraction time, so the extraction efficiency is higher.

Extraction – a method of separating solute from the solvent by extracting a substance from one solvent into another, taking advantage of its different solubility in two incompatible solvents. In fact, extraction is the motion of molecules or atoms, which is the result of atoms or molecules interacting with each other.

For example, bromine, which is more soluble in carbon tetrachloride than in water, we now want to separate bromine from water by adding bromine water to the divider, adding an appropriate amount of carbon tetrachloride, fully oscillating, standing, waiting for the mixture to stratification, you can see that the majority of bromine dissolved in carbon tetrachloride. We let the lower carbon tetrachloride flow out below, and the water flows out above, and that separates the bromine from the bromine water.

As for the effect of extraction, it mainly depends on the choice of extracted substances and extractants:
The extracted substance has a greater solubility in the extractant. The extraction agent and the original solvent do not dissolve. The extractant does not react with the extracted substance. The extractant is usually an organic solvent.

A Brief Introduction To The Extraction Thimble

310rpm Water Bath, LCD Display Standard Rotary Evaporator

RE1-W-L series-standard rotary evaporator is a water bath rotary evaporator specially developed for the needs of laboratory customers. With beautiful appearance design and suitable size, 5 Liter rotovap can be operated quickly.

Rotary vacuum evaporator price 

concessions, which are suitable for schools, laboratories, research institutes, and other experiments that need companies.

Hawach provides a

 

2L/3L/5L rotary evaporator

 

with either A or B type connection.

Features of RE1-W-L series-standard 2L & 3L & 5L rotary evaporator.

1. The temperature of the RE1-W-L series-standard rotary evaporator can reach as high as 99°C for water bath experiments. The heater will stop automatically when the temperature arrives at the set figure. Rotary vacuum evaporator price is the most economic for high-speed 310rmp/min water bath.
2. Rotary speed can be adjusted by an electronic step-less speed regulation system. Rotary speed for 

2-liter rotovap and 3L rotary evaporator can be set to 310rpm/min. But that for 5-liter rotovap can only reach as high as 200rmp/min.

3.  Apart from the large double flux condensation area, there is a drop point under the condenser and also with backflow prevention design to maximize the distillation process of a 5L rotary evaporator.
4. The integral Teflon bath is equipped with a totally enclosed heating tube, which is safe and reliable.
5. This series rotary vacuum evaporator price in Hawach products is the most cost-effective.
6. It is equipped with a vacuum gauge to observe the internal vacuum at any time. When the vacuum degree reaches the bottom, we can turn off the vacuum valve to keep the vacuum degree, decrease the noise and prolong the service life of the vacuum pump.

310rpm Water Bath, LCD Display Standard Rotary Evaporator

Triple-Stage Stainless Steel Molecular Distillation

1. Overview of molecular distillation

Wiped film vacuum distillation

 

is a special liquid separation equipment, which is different from traditional distillation such as rotary evaporator and reactors,

 

stainless steel short path distillation

 

has its unique separation principle, it relies on the different average free path of molecular movement rather than the different boiling point.

Short path wiped film distillation kit

 

has its special advantages which with high distillation efficiency and low temperature physical distillation property.

 

triple-stage stainles steel molecular distillation

 

technology is widely used in distillation, purification, solvent removing, decoloration, and deodorization of many substances, especially the heat-sensitive substance.

2. Features of molecular distillation
(1). The operating temperature of the short path molecular distillation kit is far below the boiling point of the material, and the residence time of the material is really short, which is beneficial to separate materials with the high boiling point, heat sensitive and easy oxidized.
(2). The stainless steel short path distillation can effectively remove substances in liquids such as organic solvents, odors, etc, which is a very effective method for liquid desolventizing after solvent extraction.
(3). The vacuum degree of the wiped film vacuum distillation can reach below 0.1Pa ensures the material not to be oxidized easily during distillation.
(4). The triple-stage stainless steel molecular distillation can form a liquid film less than 0.5mm, which make sure that distillation with high efficiency of heat transfer.
(5). Stainless steel short path distillation with a high degree of separation can be used to separate by conventional substances that are not easily be separated.
(6). Using short path molecular distillation kit there is no boiling or bubbling phenomenon.
(7). The wiped film vacuum distillation is a physical separation method, toxic-free harmless, pollution-free and no residue, which confirms to obtain pure and safe products.
(8). The surface of the stainless steel short path distillation was contacting with materials is made of 316L stainless steel, and the exterior surfaces of the stainless steel short path distillation are made of 304 stainless steel. Which ensures the overall thermal expansion performance and thermal insulation performance of the stainless steel wiped film molecular distillation are really good.
3. Why triple-stage stainless steel molecular distillation is needed?

Stainless steel short path distillation is a distillation method operated in a high vacuum state. This method of separating liquid mixtures by using the different free path of the molecular movement of each component in the liquid material, this wiped film vacuum distillation is widely used in food, medicine, fine chemical, and other industries applications.

However, single-stage short path molecular distillation kit also has certain defects. Because single-stage stainless steel short path distillation equipment has only one heating surface and one condensation surface, for liquid materials composed by multiple mixtures entering to the wiped film vacuum distillation, there is only once distillation in the single-stage short path molecular distillation kit, which can remove most of the lightweight molecular fractions in multiple mixed liquids, and a small portion of the lightweight molecular fractions are still present in the multiple mixed liquids, due to the mixed liquid its own characteristics or the thinness of the liquid film can not be distilled sufficiently in the single-stage stainless steel short path distillation.

If there are multiple substances need to be distilled in multiple mixed liquids by single-stage short path molecular distillation kit, then the single-stage wiped film vacuum distillation must be used again and again by adding the previous distillation product to the single-stage stainless steel short path distillation equipment and reset the distillation temperature every time.

In this way not only has complicated operation and high cost, but also the product after previous distill by the wiped film vacuum distillation equipment cannot guarantee the quality and purity, due to the influence of temperature, liquid film thickness, distillation time and other factors. Therefore, the production of a multi-stage short path molecular distillation kit is very meaningful. Then the triple-stage stainless steel molecular distillation not only can get the different components from the mixed liquids at one time but also the distillation quality and purity can be improved, which can largely avoid repeated operations, labor loss and material loss.

Triple-Stage Stainless Steel Molecular Distillation

Always Ready For Your Filtration, With the Magic of Vacuum Filtration

The scientists are doing filtering in the lab almost every day. It is difficult to imagine how we can achieve effective separation without filtration tools, such as vacuum filtration, which is an essential part of many purification systems.

Before you take the vacuum filtration into practice, you should pay attention to some considerations.

First, make sure that the glass you are going to use in your vacuum filtration can stand the pressure of vacuum filtering. For this reason, the borosilicate of high-quality glass is always recommended.

Second, the filter paper is the main factor that reduces the flow rate at a different speed. That’s why we use vacuum filtration to increase the flow rate and save time. On the other hand, if the vacuum is too strong, it will damage the filter paper.

Third, you can discard, reuse, or process the residue which is left on the filter paper again, depending on what you are filtering. The filter can also catch other solid particulates, such as catalysts, salts, impurities.

Hawach is always ready to provide a wide selection of essential vacuum filtration equipment and supplies for the labs all around the world, large and small. Now, we will introduction Hawach diaphragm vacuum pumps for you from the application area, operation, and performance optimization.

Application Area of Diaphragm Vacuum Pumps

Diaphragm vacuum pump provides advanced design, high working efficiency, and long service life, which is a replacement product with high and new technology. It is mainly used in the fields of medical and pharmaceutical product analysis, filtration of pharmaceutical products analysis, fine chemical industry, biochemical pharmaceutical industry, food inspection, and so on. It is a matching product for its precision chromatographic instrument and one of the necessary equipment in the laboratory. It is light and portable, and it has a wide range of applications and high corrosion resistance, so it can meet the requirements of all kinds of working environments.

Operation of Diaphragm Vacuum Pumps
Hawach diaphragm vacuum pumps adopt novel technology and materials in the production process. It uses frictionless film body motion, and thus produces no heat and no friction loss. A self-cooling exhaust system is designed to ensure continuous operation 24 hours. The pressure adjustable design can greatly meet the vacuum degree and gas flow rate in a certain range. The bearings adopt imported classic bearings, which directly guarantee smooth operation, low noise, and high working efficiency.

Performance Optimization of Diaphragm Vacuum Pumps

1. Diaphragm vacuum pump shall be installed in a clean and ventilated place, and there shall be sufficient room around it for easy inspection, maintenance and maintenance.
2. In the connection line, the user can install the valve and vacuum gauge above the inlet of the diaphragm vacuum pump, and check the limit pressure of the diaphragm vacuum pump at any time.
3. The internal components and wetted parts of diaphragm vacuum pumps are all PTFE-coated for good corrosion resistance and electricity leakage, so there is no need to install additional leak-proof equipment.
4. The vacuum booster and backing pump are all connected on a compact base frame, which makes the ingress of fluids and particles become impossible, and thereby avoiding corrosion and human intervention.
5. The diaphragm vacuum pump is equipped with high-efficiency motors, which offer good energy efficiency and higher pumping speeds, and there is no need for setting the standard in the performance class.
6. Fit-in-place design retrofits the diaphragm vacuum pump to existing systems, optimizes the operation process, and reduces the maintenance requirements.

Always Ready For Your Filtration, With the Magic of Vacuum Filtration

HAWACH To Let You Know The QuEChERS Method Comprehensively

To discuss the disadvantages or advantages of QuEChERS, you need to compare it with other technologies. We believe that the advantages of QuEChERS are obtained by comparing with other methods in many laboratories, and its shortcomings are more from personal preferences. The so-called shortcomings are not from their inherent defects. QuEChERS has undoubtedly changed the method of sample processing in pesticide residue analysis. Even those laboratories that do not use QuEChERS will use centrifuge tube extraction or dispersion matrix extraction in their methods.

Detection limit
There is another issue of note. Before the emergence of QuEChERS, the extraction solution obtained by the pesticide residue detection method generally contains 2-5g of sample per milliliter of non-polar solvent. At this time, when GC / MS (SIM mode) is used for splitless injection, the injection volume is 1 to 3 µL, and the method detection limit is generally 10 ng/g. Now unless the tester concentrates the extraction solution again, or perhaps replaces the solvent, the general QuEChERS method produces the extraction solution in acetonitrile, which is equivalent to the only 1g of sample per ml. In order to enable it to reach the detection limit of the previous method, programmable temperature vaporization (PTV) combined with large-volume injection (LVI) of 3 to 10 µL is required.

The high cost of acetonitrile
In addition, acetonitrile is a good solvent for liquid-phase methods, but completely different for gas-phase. The use of PTV-LVI can reduce the amount of solvent entering the gas chromatography column. Therefore, if the appropriate method can be used, the use of acetonitrile will not be a disadvantage for the gas phase, but acidification of acetonitrile requires care-there are some sensitive pesticide residues will degrade in acetonitrile (perhaps at least in some batches of solvents), for which we can improve the stability of such pesticide residues by acidifying acetonitrile, but there are reports showing that it can increase column loss. Acetonitrile is more expensive than other solvents, but the QuEChERS method requires only 10 to 15 ml of acetonitrile per sample.

Chlorophyll interference
Chlorophyll interference may be a potential disadvantage because even if 7.5mg GCB or 50mg ChloroFiltr adsorbent is added to each milliliter of extract, the removal rate is only 80 to 90%. For the removal of such macromolecular impurities, gel chromatography GPC has a better extraction effect than the dispersion matrix, but GPC has obvious disadvantages in terms of time, instrument cost, and reagent usage. Moreover, in the removal of fat macromolecules, the dispersion matrix extraction using C18 filler may be comparable to GPC in the freezing effect.

Liquid phase analysis
The biggest problem mainly comes from liquid phase analysis. When the ionization method is API, the ionization of the analyte will be suppressed by the impurities flowing out at the same time. Most foods do not have this problem when using QuEChERS for sample processing; but for other more complex samples, we do not know whether QuEChERS will be more suitable than other methods. Current mass spectrometry has greatly improved sensitivity, and better ion source design can minimize the occurrence of such problems, but the competition between charges during ionization is an inherent characteristic of API, which is inevitable. The isotope internal standard is not suitable for all analytes, so the inspector has to evaluate the matrix effect, and the quantitative results of LC-API-MS can only be treated with caution before finding a solution.

HAWACH To Let You Know The QuEChERS Method Comprehensively

Volume Of The Sample Vial

Most of the sample vials are made of glass, in addition to glass, there are other materials such as polypropylene、polymethylpentene.
Classification of laboratory glass is based on its water resistance USP( American pharmacopoeia).In general, USP Types II, III, and NP sodium calcium glass, chemical tolerance are not as good as borosilicate glass.

Polypropylene (also called as PP) is a hard material that can be processed into multiple colors and has good chemical tolerance and is suitable for short-term storage of most laboratory chemicals. When aromatic or halogenated hydrocarbons are used, their tolerance decreases with time. Because of the low ion content and can be cleaned with dilute acid and deionized water, PP sample vials are often used in ion chromatography. Because sealed can be directly incinerated, so PP sample vials also reduce the exposure of harmful substances.

Polymethylpentene (known as TPX) is a hard, transparent material, provided with a high melting point and a range of 0°-170°C. Because of its high transparency, TPX sample vials can replace opaque PP. Its chemical tolerance is similar to that of PP, TPX sample vials are usually used where visual samples or high temperature use is required. TPX sample vials are brittle at room temperature.

There is no exact concentration, which is determined by a variety of factors.
The minimum injection concentration is generally determined by the minimum detection limit or the quantitation limit. The method for detecting the content needs to determine the quantification limit. The item for the purpose of impurity inspection needs to determine the detection limit. This limit concentration is the effective minimum injection concentration.

The highest concentration is generally verified by measuring 120% ~ 200% of the limit concentration. For example, when the sample concentration is determined to be 1mg / ml, the highest concentration can be verified to 1.2mg / ml; for example, the concentration of the sample vial impurity A control solution If it is 1μg / ml, the highest concentration can be verified to 2μg / ml.

The maximum / minimum concentration of sample vial injection is related to the following factors:
1. The detection capability of the detector. The detection capabilities of detectors such as ultraviolet, evaporative light, differential, and fluorescence vary. Among them, the sensitivity of the UV detector, the energy of the light source, the permeability of the flow cell, and the degree of cleanliness will all determine the detection capability of the UV detector.
2. The response value of the substance. The signals detected by different substances under the same detector have different sizes, which are also at a concentration of 1 mg/ml. The response values ​​of substance A and substance B may differ by as much as 2, 10, or even 100 times.
3. Ultraviolet detection wavelength. The response value of the same substance at different ultraviolet wavelengths is different, which is related to the absorption value of the substance at that wavelength.
4. Chromatography column. Sometimes the concentration of the substance is too high to exceed the loading range of the column, which will cause the substance to form “flat peak” or peak bifurcation, shoulder peak, poor symmetry, and other separation problems, affecting the highest concentration. Some chromatographic columns will adsorb substances, and the effect may be very small when the amount is high, but at very low concentrations, the minimum detection limit that can be achieved by different sample vials may be different.
5. Verification by methodology. The concentration range actually applied to the formal inspection method should actually prove the rationality and feasibility of the concentration through a series of methodological verifications. In the methodological verification, the scope of the method should be verified by linear test, recovery test, repeatability test, specificity test, system suitability test, and a series of durability tests within the concentration range.

Volume Of The Sample Vial

Superior Silica Gel Flash Column And Protect The Flash Column

Excellent Separation and Purification Performance
Superior silica gel flash column adopts high capacity silica gel for accurate filling, which gives it very excellent separation and purification performance. The surface area of high capacity spherical silica gel is 40% higher than that of ordinary spherical silica gel, and the sample size is twice that of ordinary spherical silica gel. Meanwhile, the surface area is 40% higher than normal spherical silica gel; a higher sample size means smaller, faster, and more economical chromatographic columns used for separation; less solvent use, and higher separation.

Good Reproducibility and Medical Grade Materials
Superior silica gel flash column is automatically filled with proprietary technology, the column bed is tight and uniform, and there is no “ditch flow effect “. Positive and inverse silica gel fillers with different particle sizes allow users to freely select different fast separation columns in terms of separation degree, sample size, and flow rate according to different economic and efficiency requirements. The rapid separation column is made of medical-grade polypropylene material, which avoids the dissolution contamination of separated samples by ordinary PP materials. Additionally, transparent PP material cylinders allow users to visually observe sample separation.

How to protect the column

The key to maintaining long column life is proper sample handling before injection. You must prevent pumping compounds that are very hydrophobic/different from the polarity of the mobile phase into the column, whether from the mobile phase or the sample. In particular, the introduction of particulate impurities should be prohibited.  These will eventually increase the operating pressure and is very difficult or impossible to remove.

Be sure to use a guard column, because contamination of the sample and eluent may cause an increase in column pressure and affect selectivity. For Hawach columns, we recommend using the correct type of guard column. The packing material of this column is similar to that of the chromatography column used for analysis. The guard column needs to be replaced when the column pressure increases or the column efficiency is observed to decrease.

Attention during storage:

Do not store the column in a column filled with buffer or other salt-containing eluents. Storage solvents should contain at least 20% organic solvents to prevent the growth of bacteria.

Possible causes of loss of column efficiency:

Extra peak broadening. When using columns with small diameters or short lengths, peak broadening may be more apparent. To ensure that the length and the inner diameter of the pipeline is kept small. Check the injection volume and detector to check whether the cell volume is suitable for the column volume.

The equilibration time for elution is not enough.
Incorrect column temperature.
Incorrect correction density.

An excessive elution flow rate was used. Reverse the column and use a low flow rate.

Superior Silica Gel Flash Column And Protect The Flash Column