GAS CHROMATOGRAPHIC-MASS SPECTROMETRIC DETERMINATION OF ESTERS OF O-PHTHALIC ACID IN PHARMACEUTICAL ETHANOL COUPLED WITH EMULSION LIQUID-PHASE MICROEXTRACTION PRECONCENTRATION
Joint Event on 4th International Conference on GASTROENTEROLOGY AND HEPATOLOGY & 9th World Congress on CLINICAL PHARMACY & PHARMACY PRACTICE
March 25-26, 2019 | Amsterdam, Netherlands
Krylov V, Mosyagin P and Mysyagina E
Nizhny Novgorod State University, Russia
Posters & Accepted Abstracts : Arch Gen Intern Med
Dialkyl-o-phthalates are very dangerous compounds. In this study the high sensitive gas chromatographic- mass spectrometric determination of phthalates in ethanol coupled ultrasound-assisted emulsification- microextraction was developed. In the case of preconcentration of impurities from ethanol dilution was carried out with purified water. n-Octane, n-hexane and m-xylene were used as extractants. De-emulsification of extracts was carried out by centrifugation and flotation.The sources of possible systematic errors were investigated: leaking of o-phthalates from chromatographic septum; contamination of phthalates in solvents; influence of ethanol; the hydrolysis of o-phthalates and others. For the first time it is shown that the impact of these factors can lead to an overestimation or underestimation of the actual concentration of impurities by 1-2 orders of magnitude. The methods of accounting or elimination of systematic errors are proposed. Purification of solvents by Rayleigh distillation method allows to obtain samples with impurity content lower than (1-4)∙10-3 mgL-1. Containers for sampling and storage of samples to be analyzed should be made of borosilicate glass or quartz. The limits of detection of esters of о-phthalic acid are at the level of 10-6–10-5 mgL-1 and are highly competitive with the best world results. The content of o-phthalates in ethanol was 0.01-30 mgL-1. The relative expanded uncertainty of the determination of toxicants is at the level of 13- 30%.