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An accurate method combining high performance liquid chromatography (HPLC) with diode array detection (DAD) and ion-trap time-of-flight mass spectrometry (IT-TOF/MS) was developed for simultaneous identification and quantification of 34 water-soluble synthetic dyes in foodstuff. Fragmentation patterns of synthetic dyes were proposed based on IT-TOF/MS. The molecular ion [M+H] + was not observed in the conventional single-stage mass spectra for most of synthetic dyes. The single-stage mass spectra of synthetic dyes all afforded the diagnostic ions [(M- n Na+ n H)+H] + or [(M- n Na+ n H)-H] − in the positive or negative mode. Doubly charged ions were the characteristic ions of azo dyes. An HPLC–DAD method was developed to analyze 34 synthetic dyes in foodstuffs. The limits of detection (LOD) for the dyes were 0.01–0.05 μg/mL. The recoveries were between 76.1% and 105.0% with a RSD ranging from 1.4% to 6.4%. This method was successfully applied to analyzing the 34 water-soluble synthetic dyes in 21 commercial foods. [ABSTRACT FROM AUTHOR]

Aminoglycosides are a class of broad-spectrum antibiotics with several clinical uses. Owing to the ototoxicity and nephrotoxicity of aminoglycosides, therapeutic drug monitoring is required. This study aimed to devise a high-throughput method for identification and quantitative determination of aminoglycoside antibiotics in human plasma samples using ultra-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UPLC-Q-ToF-MS). Plasma samples (100 µL) spiked with five aminoglycosides (streptomycin, spectinomycin, amikacin, kanamycin, and gentamycin) and an internal standard (ribostamycin) were diluted and centrifuged in aqueous formic acid and acetonitrile. The clear supernatant extract was evaporated and reconstituted in the mobile phase, of which 4 µL was subjected to UPLC-Q-ToF-MS. Prominent peaks were observed for the drugs within 3 min. The recoveries of five aminoglycosides from plasma samples were 92.6-120%. The regression equations showed excellent linearity (0.9999 ≥ r 2  ≥ 0.9987) within the range of 1.0-100 µg/mL, and detection limits of 0.5-2.0 µg/mL. The coefficients of the intra- and inter-day variations for five drugs were less than 11.8%, while the accuracy of quantitation was in the range of 89-111%. In this study, a novel method was presented for identification and determination of aminoglycosides in human plasma samples using UPLC-Q-ToF-MS analysis. This method can be applied to high-throughput analysis used for clinical and environmental purposes.

Objective: Is to study the features and to develop the methods for the determination of thiabendazole in the tissues of cadaveric organs and blood. When performing the experiments the methods of TLC, GC-MS and spectrophotometry were used. The advantages were substantiated and the optimal conditions for the release of thiabendazole from the tissues of organs and blood with acetone were determined. A variant of purification of the substance extracted from biomatrixes by the method of column chromatography of normal pressure (sorbent L 40/100 μm, mobile phase acetone-dichloromethane (9.5: 0.5)) is proposed. To identify the analyte by TLC the Sorbfil plates were used and a toluene-acetonitrile mobile phase (2:8). When identifying thiabendazole by a combination of gas-liquid chromatography and mass spectrometry (fragmentation of molecules by electron impact 70 eV) an HP-5MS column 30 m × 0.25 mm with a non-polar stationary phase (5% -phenyl) -methylpolysiloxane was proposed. The expediency of the spectrophotometric determination of thiabendazole on the basis of absorption in an acetonitrile medium has been shown. Methods for the determination of thiabendazole in tissues of organs and blood have been developed and validated. It is shown that the techniques meet the requirements of linearity, selectivity, correctness, precision and stability. The limits of detection of thiabendazole in the liver and blood are 0.14 and 0.10 mg, respectively; the limits of quantitative determination are 0.26 and 0.18 mg per 100 g of biomatrix.

The objective of this work was to study peculiarities of identification of 2,4-di-tert-butyl hydroxybenzene (2,4-DTBHOB) in blood and the tissues of various organs with the use TLC, UR- and UV-spectrophotometry. The results of the study suggest the expediency of the application of ethylacetate as the extractive agent for the isolation of 2,4-DTBHOB from the biological materials. The optimal conditions for 2,4-DTBHOB extraction by this method were developed based on the decontamination of the analyte by means of removal of the organic substances of biological matrices using the L 40/100 mcm sorbent columns with the hexan/dioxane mixture (8.5:1.5) as the mobile phase. The method for the determination of 2,4-di-tert-butyl hydroxybenzene in the tissues of various organs (namely, liver) and blood has been developed. The proposed method allows to determine the minimal quantities of 2,4-DTBHOB present in the biological objects equivalent to 0.36 mg and 0.28 mg in the hepatic tissue and blood respectively.