Investigation on amitraz, coumaphos and thymol concentrations in honey produced by Slovenian beekeepers in 2020

A survey on concentrations of veterinary drug residues amitraz, coumaphos and thymol in honey, produced in year 2020 by Slovenian beekeepers, was conducted. 100 samples were analysed: 22 from organic and 78 from conventional production, with two analytical methods. In method for determination of coumaphos and thymol samples were extracted with acetone, petroleumether and dichlorometane. In method for determination of amitraz and its degradation products, samples were hydrolisated with HCl and NaOH, extractied with n-hexane and derivatisated with heptafluorobutyric anhydride. Determination in both methods was performed with gas chromatograph coupled with mass spectrometer. Measured concentrations of amitraz, coumaphos and thymol were in the range of 0.01-0.12 mg kg-1, 0.02-0.06 mg kg-1 and 0.08-0.17 mg kg-1, respectively. In 61 % of samples analysed no residues of amitraz, thymol and coumaphos were found. Data obtained were compared with the data from literature. Chronic and acute exposure were calculated for consumers. Maximum chronic exposure for amitraz and thymol was 0.1 % and 0.05 % of acceptable daily intake, respectively. Maximum acute exposure for amitraz and thymol was 4 % and 0.8 % of acute reference dose, respectively

Comparison of 3 Derivatization Methods for the Analysis of Amphetamine-Related Drugs in Oral Fluid by Gas Chromatography-Mass Spectrometry

The heptafluorobutyric anhydride (HFBA), pentafluoropropionic anhydride (PFPA), and trifluoroacetic anhydride (TFAA) are compared as derivatizing reagents to use as the optimal method for the analysis of 10 amphetamines and cathinones in oral fluid. The target compounds were amphetamine (AMP), methamphetamine (MA), 4-methylamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxy- N-ethylamphetamine (MDEA), cathinone (CAT), methcathinone, mephedrone, and ephedrine. Amphetamine-D5, MA-D5, MDA-D5, MDMA-D5, and MDEA-D5 use as internal standards (IS). The analytes and IS were extracted from 0.5 mL of oral fluid by ethyl acetate in the presence of NaOH (0.1 N) as the base and then the dried extracts were derivatized with HFBA, PFPA, or TFAA at 70°C for 30 minutes. The limits of quantification based on signal-to-noise ratios ≥10 were ranged between 2.5 and 10 ng/mL. The calibration graphs were linear in the range of 5 or 10 to 1000 ng/mL for all analytes. Based on sensitivity, the PFPA is proved to be the best for derivatization of the target compounds prior to gas chromatography-mass spectrometry analysis.

Different behavior of 3-nitrotyrosine and tyrosine toward perfluorinated reagents suitable for one-step preparation of volatile derivatives

In view to develop a gas-chromatographic (GC) determination of the 3-nitrotyrosine (NY)/tyrosine (Y) ratio as a marker of nitro-oxidative stress, different reagents were tested with the objective of obtaining a single volatile fluorinated product for each amino acid by a one-step derivatization procedure. The heptafluorobutyric anhydride (HFBA) /heptafluorobutanol (HFBOH) mixture proved unsuccessful for NY and Y simultaneous analysis. The reaction with different chloroformates [isobutyl chlorofomate (iBuCF) and ethyl chloroformate (EtCF)] in the presence of different perfluorinated alcohols such as trifluoroethanol (TFEOH) and HFBOH was investigated. Combination EtCF/fluorinated alcohols yielded derivatives of NY and Y as single peaks suitable to the GC determination of the NY/Y ratio. The different behaviour of two amino acids in the used reaction mixtures and the parameters influencing the results were discussed.