Detection of recombinant bovine somatotropin in milk and effect of industrial processes on its stability.

A LC-MS/MS method has been developed for the direct detection of recombinant bovine somatotropin (rbST) in milk and dairy products. The sample preparation protocol is based on a solid phase extraction step followed by precipitation with cold methanol and enzymatic digestion. The analysis is focused on the tryptic N-terminal peptide, specific of the recombinant form of the hormone and the detection is performed by LC-ESI(+)-MS/MS.

Identification of cows treated with recombinant bovine somatotropin.

A method for the specific detection and quantification of recombinant bovine somatotropin (rbST) in bovine blood has been validated according to criteria described in the EU Commission Decision 2002/657/EC. The method is based on a thorough purification procedure followed with the detection by LC-ESI-MS/MS of the tryptic N-terminal peptide specific of the rbST. The recombinant equine somatotropin (reST) is used as internal standard.

Elimination kinetic of recombinant somatotropin in bovine.

Bovine somatotropin (bST), also called growth hormone is a protein hormone produced by the pituitary gland and responsible directly or indirectly for various effects on growth, development and reproductive functions. Its recombinant bovine somatotropin form (rbST) is used in dairy cattle to enhance milk production. Even if the effects of treatment with rbST have been largely studied, until now analytical methods able to detect rbST were limited to immunoassays, which suffer from the impossibility to distinguish between the endogenous and the recombinant form.

Direct determination of recombinant bovine somatotropin in plasma from a treated goat by liquid chromatography/high-resolution mass spectrometry.

Recombinant bovine somatotropin (rbST) is used in dairy cattle to enhance milk production. Despite the ban on this hormone in some countries, especially in Europe, there is so far no method available for the direct detection of rbST either in milk or in plasma. An analytical strategy has been developed to analyze rbST in plasma, including a purification procedure based on a precipitation with ammonium sulphate, followed by a solid-phase extraction (SPE)-based clean-up on C4 sorbent and precipitation with cold methanol.

Multi-screening approach to monitor and quantify 42 antibiotic residues in honey by liquid chromatography-tandem mass spectrometry.

A multi-screening approach for monitoring potential chemical contaminants in honey by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) has been developed. A total of 42 veterinary drugs (5 tetracyclines, 7 macrolides, 3 aminoglycosides, 8 beta-lactams, 2 amphenicols and 17 sulfonamides) were surveyed with the ultimate goal of unambiguously confirmed and quantified these analytes at a concentration level of 20 microg/kg. A basic sample preparation including four subsequent liquid/liquid extraction steps was necessary to adequately extract the compounds of interest from the honey.

Evaluation of atmospheric pressure ionization interfaces for quantitative measurement of sulfonamides in honey using isotope dilution liquid chromatography coupled with tandem mass spectrometry techniques.

A comparison was made between electrospray, atmospheric pressure chemical and atmospheric pressure photospray ionizations to evaluate the MS/MS responses of standard sulfonamides and honey spiked samples. The sample preparation entails an acidic hydrolysis followed by a liquid/liquid extraction. Full method validation was realised by LC-APPI-MS/MS.

Validation and comparison of the Copan Milk Test and Delvotest SP-NT for the detection of antimicrobials in milk.

The Delvotest SP-NT and Copan Milk Test, two microbiological tests designed for screening antimicrobial substances in milk were compared and validated. The performance criteria described by the European Decision 2002/657/EC were used for the study. Both tests were evaluated with visual and automated reading (scanner) and the validation was performed on 10 different antibiotics (penicillin-G, cloxacillin, sulfamethazine, sulfadiazine, oxytetracycline, gentamicin, cephalexin, cefquinome, dihydrostreptomycin and trimethoprim).