Liquid chromatographic-mass spectrometric analysis of glucuronide-conjugated anabolic steroid metabolites: method validation and interlaboratory comparison.

Liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method for simultaneous and direct detection of 12 glucuronide-conjugated anabolic androgenic steroid (AAS) metabolites in human urine is described. The compounds selected were the main metabolites detected in human urine after dosing of the most widely abused AAS in sports, e.g. methandienone, methenolone, methyltestosterone, nandrolone and testosterone, and certain deuterium-labeled analogs of these metabolites. Sample preparation and the LC-ESI-MS/MS method were optimized, validated, and the overall process was implemented and the results between seven laboratories were compared. All the metabolites were extracted simultaneously by solid-phase extraction (SPE) and analyzed by LC-ESI-MS/MS with positive ionization mode and multiple reaction monitoring (MRM). Recovery of the SPE for the AAS glucuronides was 89-100% and ten out of twelve compounds had detection limits in the range of 1-10 ng/ml in urine. The results for inter/intraday repeatability were satisfactory and the interlaboratory comparison with authentic urine samples demonstrated the ease of method transfer from one instrument setup to another. When equivalent triple quadrupole analyzers were employed the overall performance was independent from instrument manufacturer, electrospray ionisation (ESI) or atmospheric pressure chemical ionization (APCI) and liquid chromatohraphic (LC) column, whereas major differences were encountered when changing from one analyzer type to another, especially in the analysis of those AAS glucuronides ionized mainly as adducts.

Enzyme-assisted synthesis and structure characterization of glucuronide conjugates of eleven anabolic steroid metabolites.

Enzyme-assisted in vitro synthesis of eleven glucuronide-conjugated anabolic androgenic steroid (AAS) metabolites was performed using biphenyl-induced rat liver microsomal enzymes. The substrates within the study were the main compounds and metabolites detected in human urine after dosing of, e.g. metandienone, metenolone, methyltestosterone, nandrolone, and testosterone. Yields of glucuronidation reactions were 13-28% for most compounds, but significantly higher (77-78%) for the substrates with 4-ene-3-one double bond system of the steroid A-ring. Characterization of glucuronide-conjugated AAS structures was based on nuclear magnetic resonance spectroscopy ((1)H NMR) and on liquid chromatographic-mass spectrometric (LC-MS) and tandem mass spectrometric (LC-MS/MS) analyses in positive and negative ion mode electrospray ionization (ESI). Only minor differences were observed in optimal synthesis conditions between various substrates, which offer a potential to apply this in vitro assay as a default method for glucuronidation of new AAS substrates. The method allowed for a rapid production pathway of stereochemically pure AAS glucuronides in milligram amount, such as needed, e.g. in the development of analytical methods in forensic or pharmaceutical sciences, as well as in doping control.

Analysis of anabolic steroids in urine by gas chromatography-microchip atmospheric pressure photoionization-mass spectrometry with chlorobenzene as dopant.

A gas chromatography-microchip atmospheric pressure photoionization-tandem mass spectrometry (GC-µAPPI-MS/MS) method was developed for the analysis of anabolic androgenic steroids in urine as their trimethylsilyl derivatives. The method utilizes a heated nebulizer microchip in atmospheric pressure photoionization mode (µAPPI) with chlorobenzene as dopant, which provides high ionization efficiency by producing abundant radical cations with minimal fragmentation. The performance of GC-µAPPI-MS/MS was evaluated with respect to repeatability, linearity, linear range, and limit of detection (LOD). The results confirmed the potential of the method for doping control analysis of anabolic steroids. Repeatability (RSD<10%), linearity (R(2)≥0.996) and sensitivity (LODs 0.05-0.1ng/mL) were acceptable. Quantitative performance of the method was tested and compared with that of conventional GC-electron ionization-MS, and the results were in good agreement.

Feasibility of gas chromatography-microchip atmospheric pressure photoionization-mass spectrometry in analysis of anabolic steroids.

Mass spectrometers equipped with atmospheric pressure ion sources (API-MS) have been designed to be interfaced with liquid chromatographs (LC) and have rarely been connected to gas chromatographs (GC). Recently, we introduced a heated nebulizer microchip and showed its potential to interface liquid microseparation techniques and GC with API-MS. This study demonstrates the feasibility of GC-microchip atmospheric pressure photoionization-tandem mass spectrometry (GC-µAPPI-MS/MS) in the analysis of underivatized anabolic steroids in urine. The APPI microchip provides high ionization efficiency and produces abundant protonated molecules or molecular ions with minimal fragmentation. The feasibility of GC-µAPPI-MS/MS in the analysis of six selected anabolic steroids in urine samples was studied with respect to intra-batch repeatability, linearity, linear range, and limit of detection (LOD). The method showed good sensitivity (LODs 0.2-1 ng/mL), repeatability (relative standard deviation<10%), and linearity (regression coefficient≥0.9995) and, therefore, high potential for the analysis of anabolic steroids. Quantitative performance of the method was tested with two authentic urine samples, and the results were in good agreement with those obtained with conventional GC-electron ionization-MS after derivatization.