Vol 71, No 10 (2016)

A survey of electrophoresis methods for the determination of pesticides from different classes in environmental materials and food products is presented. The main sample preparation procedures, the cleaning of extracts, and the use of various versions of capillary electrophoresis are considered.

Sources of new analytical techniques, mainly quantitative, are considered. The birth of novel techniques of quantitative analysis is usually associated with the finding and use of characteristics (properties) of an object, specifically related to the component concentration. The success of such a search substantially depends on the possibility of monitoring advances in many branches of science and instrumentation and of their assessment from the viewpoint of suitability and prospects for analysis.

Experimental results are reported on the effect of the procedure of sampling, storage conditions, and sample preparation of saliva on the concentrations of trace elements determined by atomic emission digital spectrography of liquid samples with spectrum excitation from their dry residues in an AC arc at a tip of a carbon electrode. Recommendations on the optimization of the stages of sampling, storage, and preparation of saliva samples are given.

A procedure is developed and conditions are optimized for the pretreatment of natural water using distillation with no prefiltration of acidified water in combination with preconcentration by solid-phase extraction (SPE) on a Strata-X polymeric adsorbent followed by derivatization for the determination of trace concentrations of C3–C18 aliphatic carboxylic acids by gas chromatography with mass spectrometric detection. It is shown that, at the distillation stage, 90% of free carboxylic acids of the homologous series are transferred to the distillate, which greatly facilitates the procedure of the analysis of natural water containing impurity particles and humic substances and ensures the achievement of the limit of detection for the analytes about 0.05 μg/L. It is found that, at the SPE stage, the adsorbents based on copolymers of styrene, divinylbenzene, and N-vinylpyrrolidone in plastic cartridges may serve as sources of additional pollution with benzoic, palmitic, and stearic acids in the eluates under investigation.

A procedure is developed for the gas chromatographic determination of lower aldehydes as dibutoxyalkanes and carboxylic acids as butyl esters by the reaction with tributyl borate in an aqueous medium. Derivatization conditions were optimized. The procedure was used to determine side products in glyoxal synthesized by the catalytic oxidation of ethylene glycol.

A procedure is developed for determining 11 β-agonists, that is, hormonal growth promoters for farm animals, using HPLC with mass spectrometric detection. The procedure includes the enzymatic hydrolysis of homogenates of organs and tissues of animals (longissimus muscle, liver, and kidney), precipitation of proteins with perchloric acid, extraction of β-agonists with a mixture of isopropyl alcohol–ethyl acetate (6: 4), purification of the extract by solid phase extraction using a Bond Elut cartridge, HPLC separation in the gradient elution mode, electrospray ionization, and mass spectrometric detection in the multiple reaction monitoring mode. The procedure is certified. The analytical range is 1.0–100.0 μg/kg.

A device is developed for automated immunochromatographic assay, designed for one-time tests at the place of occurrence of a disease. The device comprises a turntable platform for up to five strips placed simultaneously, a unit for sample collection and microdosing to a test strip, a detection unit, and a microprocessor control system. A manual, semiautomatic, or automatic operation mode may be selected. Colloidal quantum dots with a luminescence peak from the visible to near-infrared spectral region (600–800 nm) are used as fluorescent labels. A UV-LED or a laser at 365–480 nm can be used as an excitation system; the detection device is a spectrometer with an operation range of 500–800 nm, based on a CCD series of TCD1304DG sensors (Toshiba). RFID tags of samples can re read and the analysis results can be sent to an external computer. The device is made in a plastic case for carrying.