The chromatographic processes in the S-chamber with the counter plate.

For the first time the chromatographic processes in the new variant of a S(min)-chamber with a counter plate (a S(min)(CP)-chamber) positioned at a small distance above a separating plate have been studied, given the adsorption layers of the both plates (the separating plate and the counter plate) are turned to each other. It should be noted that the features of this method have not been completely studied, only two publications were devoted to the practical using of the S(CP)-chamber. Using of a dry counter plate in the S(min)-chamber having been proposed by us recently leads to the marked increase in the volume of the mobile phase that continuously migrates through the separating plate. Using of the S(min)-chamber with the dry counter plate for separation allows, first, substantially (up to 50%) increasing the value of R(f) (especially, in the range of the small meanings of R(f) (0-0.3)), second, increasing the efficiency of separation by 2.0-2.5 times, and, third, increasing the peak resolution of the method by ∼25%. It should be noted that although when separating a mixture in the S(min)(CP)-chamber a slight increase in the experiment duration also occurs (by 20-50% depending on the sizes of the used plate), in all the cases chromatographic characteristics markedly improve (in comparison with separation in the same conditions, but without using of the counter plate).

Gas chromatography analysis of benzene, toluene, ethylbenzene and xylenes using newly designed needle trap device in aqueous samples.

A newly designed needle trap device with Carbopack X as a sorbent material is used for sampling, preconcentration and injection of volatile analytes benzene, toluene, ethylbenzene and xylenes (BTEX) into gas chromatograph. The closed system of stripping the analytes from water samples was used. An injection port with a modified metal liner was used to desorb analytes trapped in needle trap device. The main advantage of needle trap device consists in the simple methodology and easiness and rapidity of the analysis. Needle trap device is suitable for sampling in field. The experimental parameters as breakthrough volume of stripping gas, linearity, repeatability and limit of detection (LOD) and quantification (LOQ) were investigated. LOD ranges from 0.05 to 0.07 microgL(-1) and relative standard deviation ranges from 0.5% to 11.6% at concentrations 5 and 0.1 microgL(-1), respectively.

Ultra-short open capillary columns in gas-liquid chromatography.

New area in capillary gas chromatography (GC) was investigated. Many important analytical tasks can be solved only use very short capillary columns. Variation of chromatographic characteristics of ultra-short capillary columns with column length was originally studied at the conditions of gas-liquid chromatography. The column length varied from 500 to 10 cm. Dependencies of height equivalent to one theoretical plate (HETP) and separation number (SN) on carrier gas velocity were considered for columns of various length. Field of ultra-short open capillary columns in gas-liquid chromatography has the following peculiarities: (1) more shorter retention times of sorbates, (2) more low temperatures of short column, that has as final result (a) high selectivities of used column and (b) the possibilities to separation more thermal lability compounds. It was shown that short capillary columns can be successfully used at both isothermal and temperature programming conditions for express-analysis at lower oven temperatures. Examples of express-analysis (high speed), analysis of high boiling and thermolabile compounds are listed, which demonstrate some radically new applications of capillary gas chromatography.

Needle concentrator for gas chromatographic determination of BTEX in aqueous samples.

A simple method of solventless extraction of volatile organic compounds (BTEX) from aqueous samples was developed and validated. A new arrangement of the full volume inside needle capillary adsorption trap (INCAT) device with Porapak Q as a sorbent material and wet alumina as a source of desorptive water vapour flow in a closed analytical system is presented. The analytical characteristics of developed device and of compared purge-and-trap (PTI) device for BTEX compounds are similar; the limits of detection as well as quantification are lower than 1 microg l(-1).

Poly[1-(trimethylsilyl)-1-propine] as chromatographic adsorbent and prospects of its application in packed and capillary columns.

The application of film-forming organic polymers, which are in common use in membrane technology, as chromatographic adsorbents for packed and capillary columns has been suggested. The chromatographic characteristics of poly[1-(trimethylsilyl)-1-propine] (PTMSP) as an adsorbent were studied. The film-forming properties of PTMSP simplify manufacturing of capillary and packed gas-solid columns. It was shown that separation of C1-C4 hydrocarbon gases on the columns with PTMSP is of practical interest. In the authors' opinion, PTMSP is also promising for the separation of inorganic gases.