Determination of trenbolone and its metabolite in bovine fluids by liquid chromatography-tandem mass spectrometry.

A liquid chromatographic-tandem mass spectrometric (LC-MS-MS) method has been developed for the determination of trenbolone in bovine urine and serum. The aim was a control of the misuse of trenbolone in food-producing animals. The procedure involved, in both cases, a preliminary solid-phase clean-up followed by a liquid-liquid extraction for urine samples after a preliminary enzymatic hydrolysis. The extracts have been directly analysed by reversed-phase LC-MS-MS in selected reaction monitoring (SRM), acquiring two diagnostic product ions from the chosen precursor [M+H](+). The procedures were validated across the concentration range of 1-1500 ng/ml. The linearity, the inter- and intra-day accuracy and precision have been determined. The procedure was specific and the accuracy values were better than 20% at the limit of quantitation of spiked samples. The limit of quantification (LOQ) and the limit of detection (LOD) were, respectively, 1 ng/ml and 350 pg/ml for urine and serum. According to the draft, SANCO/1805/2000, we determined the decision limit CCalpha and the detection capability CCbeta. The recovery values for urine ranged from 87 to 128%, and for plasma the recovery was 70+/-4%. The procedure proved to be simple and suitable for routine and confirmatory purposes such as those developed for residue studies.

Determination of flumethasone in calf urine and serum by liquid chromatography-tandem mass spectrometry.

Corticosteroids can be illegally administered to cattle as growth promoting agents to improve meat production. We developed a liquid chromatography-atmospheric pressure ionization mass spectrometry-mass spectrometry (LC-MS-MS) method able to identify and quantify flumethasone, one of the most potent fluorinated synthetic corticosteroid, in serum and urine from treated calves. The analyte was purified from urine (conjugated and free, following enzymatic hydrolysis) and from serum by C18 solid-phase and liquid-liquid extractions, then analyzed by LC-MS-MS monitoring the product ions of an abundant precursor (SRM in negative ionization mode). Results on flumethasone residues in biological fluids in three calves treated at different levels are presented. This method allowed the detection of flumethasone in bovine urine and serum at the 30-pg/ml level.

CZE determination of somatostatin in pharmaceutical preparations.

We propose a simple and accurate method for CE quantitative determination of somatostatin in pharmaceutical preparations. The method is specific for somatostatin as indicated by the resolution between the analyte and the analogue peptides which differ from somatostatin by one aminoacid. The linearity range is from 0.02 to 0.35 mg/ml. The recovery of the somatostatin from a pharmaceutical product is about 100.0%.

Determination of cows' milk in goats' milk and cheese by capillary electrophoresis of the whey protein fractions.

The use of capillary zone electrophoresis to determine the adulteration of cows' milk in goats' milk products is described. The detection and quantification of cows' milk was based on the presence of the specific whey proteins: the relative calibration curve is reported. The peaks of interest were well resolved by using sodium borate at pH 9.2 as background electrolyte in methyl-silanized capillaries. The minimum amount detectable of cows' milk was 2% in milk mixtures and 4% in cheeses. Restrictions due to genetic variability and possible heat treatments, on only one of the two types of milk employed, are taken into account. Qualitative analysis of goat-ewe-cow and goat-ewe samples are also reported.

Analysis of ethereal extracts of wines and other alcoholic beverages by high-performance liquid chromatography with microbore columns.

The ethereal extracts of wines, beer and vermouth were analysed by high-performance liquid chromatography. The following three characteristic peaks were first identified using GC-MS and then quantitatively determined: 5-hydroxy-methyl-2-furaldehyde, 2-(4-hydroxyphenyl)ethanol and 3-(2-hydroxyethyl)indole.

Analysis of bitter essential oils from orange and grapefruit by high-performance liquid chromatography with microbore columns.

The analysis of bitter orange and grapefruit essential oils (non-volatile fraction) was carried out by HPLC in normal- and reversed-phase mode with UV detection. These oils were compared with the sweet orange and mandarin essential oils, analyzed previously. For the identification of chromatographic peaks, fractionation by RP-HPLC was carried out. The purified fractions were analyzed by GC-MS and LC-MS. Some new compounds were found, together with many others already identified in different citrus essential oils.

Routine determination of polycyclic aromatic hydrocarbons in carbon black by chromatographic techniques.

A method is proposed for the determination of polycyclic aromatic hydrocarbons (PAHs) in carbon blacks. The PAHs are extracted from the carbon black with benzene in a Soxhlet apparatus, purified by silica gel thin-layer chromatography, weighed and analysed by gas and/or high-performance liquid chromatography. The total PAH and benzo[a]pyrene (BaP) concentrations in different types of carbon blacks and in different batches of the same carbon black were determined. It is shown that the distribution of the PAH fraction in different types of carbon blacks is almost the same but there are considerable differences in the total amount of the PAH fraction and the BaP concentration.