A system and method for purifying coenzyme Q.sub.10 are provided. The method includes: passing a CoQ.sub.10-containing crude product through a first chromatographic column to obtain a first CoQ.sub.10-containing intermediate product. The method further includes preparing, based on the first CoQ.sub.10-containing intermediate product, a second CoQ.sub.10-containing intermediate product. The method further includes passing the second CoQ.sub.10-containing intermediate product through a second chromatographic column to obtain a third CoQ.sub.10-containing intermediate product. The method further includes obtaining purified CoQ.sub.10 product by purifying the third CoQ.sub.10-containing intermediate product.

The disclosed embodiments relate to the design of a preconcentrator system for preconcentrating air samples. This preconcentrator system includes a plurality of preconcentrators that preconcentrate the air samples prior to chemical analysis, and a delivery structure comprising a manifold that selectively routes a sample airflow to the plurality of concentrators so that the plurality of preconcentrators receive a sample airflow concurrently or individually.

The disclosed embodiments relate to the design of a preconcentrator system for preconcentrating air samples. This preconcentrator system includes a plurality of preconcentrators that preconcentrate the air samples prior to chemical analysis, and a delivery structure comprising a manifold that selectively routes a sample airflow to the plurality of concentrators so that the plurality of preconcentrators receive a sample airflow concurrently or individually.

While sample extraction device including a sorbent is coupled to a sample vial containing a sample, a vacuum is drawn through the sample extraction device to evaporate the volatile matrix of the sample and carry volatilized target compounds of the sample to the sorbent. Optionally, once the volatile matrix is evaporated, the sample vial is heated and/or the vacuum level is increased to transfer heavier target compounds to the sorbent. Multiple sampling devices can be extracted in parallel. The sample extraction device can be inserted into a thermal desorption device that directly couples the sample extraction device to a gas chromatograph. In some embodiments, the sample is desorbed and analyzed using gas chromatography or another suitable technique. The techniques disclosed herein are used for analysis of volatile organic compounds and semi-volatile organic compounds in water, food, beverages, soils, and other matrices.

Disclosed is a sample pretreatment method of microextraction tube injection, comprising providing a capillary micro-extraction tube with extracting medium in it as an injector, passing a sample through the capillary micro-extraction tube, during which an analyte is extracted into an extracting medium inside the capillary micro-extraction tube; then, filling the capillary micro-extraction tube with an organic solvent and keeping the filling for a certain period of time, so that the extracted analyte is dissolved in the organic solvent inside the capillary micro-extraction tube to form an injection solution; finally, keeping one end of the capillary micro-extraction tube sealed and inserting the other end directly into an injection port of a gas chromatography, such that the injection solution is automatically ejected out from the capillary micro-extraction tube into the injection port.

A system for component interconnection for use in liquid chromatography includes a first switching valve and a second switching valve. A first connecting line fluidly connects the first switching valve to the second switching valve. A second connecting line fluidly connects the first switching valve to the second switching valve. A metering device is located in the first connecting line.

A method for reducing the variability, as measured by relative standard deviation (RSD), of an analytical testing technique is provided. This improvement in RSD improves the confidence in the values obtained during field testing. The method includes incorporating a focusing agent into the sampling media, which permits providing sampling media such as thermal desorption tubes preloaded with the focusing agent.

A sample introduction device 10 includes a tube holding section 21 and a sample removing mechanism 40. The sample removing mechanism 40 removes a sample 6 in a sample tube 2 held by the tube holding section 21. Thus, in the sample introduction device 10, the sample 6 in the sample tube 2 held by the tube holding section 21 can be automatically removed. As a result, the operator no longer needs to perform an operation of taking out the sample 6 from the sample tube 2. Thus, a work load on the operator can be reduced.

Chromatographic systems for size exclusion chromatography (SEC) are provided that comprise an inlet, an outlet, an analytic column having a first interior volume that has a first length and a first cross-sectional area normal to the first length, the first interior volume containing a first stationary phase, and a guard column having a second interior volume that has a second length and a second cross-sectional area normal to the second length, the second interior volume containing a second stationary phase. The inlet is in fluid communication with the guard column, the guard column is in fluid communication with the analytic column, and the analytic column is in fluid communication with the outlet. Moreover, the second length is smaller than the first length, and the second cross-sectional area is smaller than the first cross-sectional area.

Chromatographic systems for size exclusion chromatography (SEC) are provided that comprise an inlet, an outlet, an analytic column having a first interior volume that has a first length and a first cross-sectional area normal to the first length, the first interior volume containing a first stationary phase, and a guard column having a second interior volume that has a second length and a second cross-sectional area normal to the second length, the second interior volume containing a second stationary phase. The inlet is in fluid communication with the guard column, the guard column is in fluid communication with the analytic column, and the analytic column is in fluid communication with the outlet. Moreover, the second length is smaller than the first length, and the second cross-sectional area is smaller than the first cross-sectional area.