title: Pitfalls in trimethylsilylation of anabolic steroids. New derivatisation approach for residue at ultra-trace level.
abstract: Mixtures such as N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA), ammonium iodide and dithioerythreitol (DTE) or MSTFA, trimethyliodosilane and DTE were used for derivatisation of anabolic steroids extracted from 2 g kidney fat and present at ng kg(-1) level. They are leading to unexpected products. Their identity and mechanism of formation have been discussed. A new silylation mixture was developed to overcome these pitfalls: N,O-bis-trimethylsilyl-acetamide was used in combination of 2.5% of MSTFA/I(2) (1000:10 (v/w)). A single product consisting in ether-TMS and/or enol-TMS derivative was observed for all tested steroids with a stability demonstrated for at least 48 h. Quantitative application was proved even at the low ng kg(-1) level in a complex biological matrices, i.e. kidney fat.
authors.affiliation: Laboratoire d'Etude des Résidus et Contaminants dans les Aliments (LABERCA) Ecole Nationale Vétérinaire de Nantes, BP 50707, 44307 Nantes Cedex 3, France. laberca@vet-nantes.fr
authors.forename: Véronique
authors.initials: V
authors.lastname: Meunier-Solère
authors.forename: Daniel
authors.initials: D
authors.lastname: Maume
authors.forename: François
authors.initials: F
authors.lastname: André
authors.forename: Bruno
authors.initials: B
authors.lastname: Le Bizec
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry; D045930:Anabolic Agents / Q000737:chemistry*; D000735:Androstenedione / Q000737:chemistry; D000738:Androsterone / Q000737:chemistry; D000818:Animals; D002417:Cattle; D004355:Drug Stability; D004958:Estradiol / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D007668:Kidney / Q000737:chemistry; D008297:Male; D036103:Nanotechnology; D015203:Reproducibility of Results; D013739:Testosterone / Q000737:chemistry; D014297:Trimethylsilyl Compounds / Q000138:chemical synthesis*
chemical_list: D045930:Anabolic Agents; D014297:Trimethylsilyl Compounds; D013739:Testosterone; D000735:Androstenedione; D004958:Estradiol; D000738:Androsterone