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Gas chromatography of chlorinated pesticides in water is carried out after adsorption of a 50 mL sample using a cartridge containing 100 mg CN-bonded porous silica and extraction with 500 μL pentane. The average recovery for eight organochloride pesticides at 1 ppb was >95%. The procedure described is simple, selective and reproducible.

PLOT columns have been prepared with kaolin as the liquid phase support. These columns show good efficiency with different stationary phases and good thermal stability with polar phases. The performance of columns is shown by the separation of various mixtures such as fatty acids, phenols and anilines which are of analytical importance.

The critical factor in the preparation of glass capillary columns is the coating of the inner wall with stationary phase. Difficulty is usually met when a very polar compound has to be coated and statisfactory results are obtained only when the inside surface is roughened. Though a number of devices have been suggested, reproducible results are seldom obtained. The outstanding properties of graphitized carbon black (GCB) permit the formation of an ideal precoating of a glass capillary upon which any stationary phase can be applied. The precoating is carried out by flowing through the capillary a colloidal solution of GCB obtained by exposing a 1% solution in methylene chloride to an ultrasonic generator. A colloidal solution is obtained by means of this treatment, which after introduction into the capillary and evaporation of the solvent leaves a layer, which strongly adheres to the surface and is not even removed by washing with polar and non polar solvents. After washing the graphite surface a new stationary phase can be coated on it. A great variety of columns of different polarity can be prepared such as SP 1000, apiezon, carbowax, SE 30 and SE 52, and their characteristics are evaluated. The use of a colloidal solution prepared by ultrasonic means can be extended also to the preparation of gas solid columns.

Glass microbead columns withN, N′-bis-(p-butoxybenzilidene) α, α′-bi-p-toluidine (BBBT) a high-temperature smectic-nematic liquid crystalline stationary phase have been prepared. The best efficiency was obtained with BBBT from 0.025% w/w (ca. 1800 theoretical plates m−1) to 0.1% w/w (ca. 2100 theoretical plates m−1). Capacity ratios and separation efficiencies of columns packed with glass microbeads treated and untreated with a surfaceactive agent were studied as a function of analysis time. A separation of five methylchrysene isomers is shown.

A general procedure that should be applied when a sorbent material is examined in order to recover organic pollutants from water is shown. This method recommends determination of specific retention volumes, the break-through of test compounds and the influence on these of the interfering substances. An expanded hydrophobic perlite was characterized as a suitable adsorbent for the recover of polycyclic aromatic hydrocarbons (PAHs).