A direct screening procedure for diuretics in human urine by liquid chromatography-tandem mass spectrometry with information dependent acquisition.
BACKGROUND
Diuretics are a class of compounds largely used for either therapeutic (edemas, hypertension, etc.) or illegal (doping) purposes. Probably owing to the substantial variety of their chemical structures, which makes them hardly extractable from a biological matrix in a single procedure, a quite short list of screening methods can be retrieved in the literature.


METHODS
This work presents a screening procedure for 24 diuretics based on the direct injection of urine (after 50 folds dilution) in a LC-ESI-MS/MS system (Applied Biosytems 4000 QTrap). Two information dependent acquisitions (IDA), one in positive, one in negative ionization, allowed the acquisition of one selected reaction monitoring transition for each compound, which, when a significant peak was found, triggered the acquisition of the enhanced product ion (EPI) spectrum.


CONCLUSIONS
EPI spectra were stored in a library and the procedure was able to recognize by library matching various diuretics in real positive samples. The limits of detection were comprised between 0.002 and 0.25 mg/l and ion suppression was not found to significantly influence the analysis.
Politi
Lucia
L
Department of Legal Medicine & Public Health, University of Pavia, Via Forlanini 12, I-27100 Pavia, Italy. politi@unipv.it
Morini
Luca
L
Polettini
Aldo
A
D002853:Chromatography, Liquid / Q000379:methods*; D004232:Diuretics / Q000652:urine*; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013997:Time Factors; D014838:Volunteers
D004232:Diuretics