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Diuretics can be misused to force diuresis to achieve weight loss or to mask the intake of a prohibited substance and are therefore prohibited by the World Anti-Doping Agency (WADA). For similar reasons other masking agents (vaptans, probenecid, etc.) are also prohibited by the WADA. The currently employed methods to detect diuretics in urine use extraction or dilute-and-shoot, combined with 1D- liquid chromatography (LC) high resolution mass spectrometry (MS) or LC-triple quadrupole MS. Dilute-and-shoot methods save time and work, but these methods encounter some problems (e.g., peak drift and matrix effect). Therefore, a 2D-LC-MS/MS application was developed, validated and evaluated as an alternative. The effect of a turbulent flow rate was studied by loading samples under different conditions and the turbulent flow rate was found to be more effective in removing matrix interferences. A correlation with the specific gravity was observed. A turbulent flow online solid phase extraction (SPE) method combined with LC-MS/MS for the detection of 50 diuretics and masking agents was developed and validated for identification purposes. This method combines the advantages of dilute-and-shoot while solving the issues of matrix effect and retention time shift. Furthermore, the presented method is compliant with WADA's identification criteria and can hence be used for screening and/or confirmation., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A new doping control screening method for the analysis of diuretics and stimulants using ultra high pressure liquid chromatography-high resolution Orbitrap mass spectrometry has been developed. The screening was performed in full scan MS with scan-to-scan polarity switching which allowed to detect more than 120 target analytes. Sample preparation was limited to 10-fold dilution of the urine into the internal standard solution followed by injection. Total run time per sample was 10 min. Validation of the method yielded detection limits for diuretics between 25 and 250 ng mL(-1) and for stimulants between 5 and 500 ng mL(-1). The screening method has been implemented in routine doping control., (Copyright © 2012 Elsevier B.V. All rights reserved.)

A fast and selective liquid chromatography-tandem mass spectrometric (LC/MS/MS) method for the screening of 18 diuretics and probenecid in human urine is presented. Analyses were performed on a LCQ-Deca instrument equipped with ESI-interface using scan by scan polarity changing. All diuretics and probenecid were separated in less than 20 min after liquid-liquid extraction with ethyl acetate. The LOD for all substances was 100 ng/mL or better. The method was applied to detect diuretics after the oral administration of several drugs including hydrochlorothiazide, bumetanide, spironolactone, furosemide, amiloride, triamterene, chlortalidone and epithizide. All diuretics could be detected for periods up to 96 h after the intake of therapeutic amounts., (Copyright 2002 John Wiley & Sons, Ltd.)

Abstract: A new doping control screening method for the analysis of diuretics and stimulants using ultra high pressure liquid chromatography–high resolution Orbitrap mass spectrometry has been developed. The screening was performed in full scan MS with scan-to-scan polarity switching which allowed to detect more than 120 target analytes. Sample preparation was limited to 10-fold dilution of the urine into the internal standard solution followed by injection. Total run time per sample was 10min. Validation of the method yielded detection limits for diuretics between 25 and 250ngmL−1 and for stimulants between 5 and 500ngmL−1. The screening method has been implemented in routine doping control. [Copyright &y& Elsevier]