LIQUID-LIQUID-EXTRACTION PROCEDURE FOR TRACE DETERMINATION OF CYCLOPHOSPHAMIDE IN HUMAN URINE BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY TANDEM MASS-SPECTROMETRY
C. Sottani et al., LIQUID-LIQUID-EXTRACTION PROCEDURE FOR TRACE DETERMINATION OF CYCLOPHOSPHAMIDE IN HUMAN URINE BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY TANDEM MASS-SPECTROMETRY, Rapid communications in mass spectrometry, 12(16), 1998, pp. 1063-1068
A sensitive, specific and accurate high performance liquid chromatogra
phy/ionspray-tandem mass spectrometry procedure (HPLC/MS/MS) has been
developed to quantify cyclophosphamide in human urine from hospital pe
rsonnel involved in drug preparation and administration of antineoplas
tic alkylating agents. This methodology, which includes liquid-liquid
extraction with ethylacetate, requires no derivatization procedures, p
reventing cyclophosphamide (CP) from possible thermal and chemical dec
omposition reactions. We detected the excretion of this unmetabolized
alkylating drug in 50% of all the study participants. The amount of CP
ranged from 0.1 ng mL(-1) to 1.9 ng mL(-1) urine. This methodology wa
s validated by the use of ifosfamide as internal standard. The assay w
as linear over the range 0 to 3.2 ng mL(-1) urine, with a lower limit
of quantification of 0.2 ng mL(-1), The limit of detection was assesse
d at 0.05 ng mL(-1) urine. This method is characterized by a coefficie
nt of variation <10%, Standard calibration curves, obtained on three d
ifferent days, had correlation coefficients always greater than 0,998,
The intra and interday precision were within 11%, and accuracy was in
the range 99-103%, The mean extracted recovery assessed at three diff
erent concentrations (0.5, 0.8, 3.2 ng mL(-1)) was always more than 85
%, The extraction efficiency of cyclophosphamide from urine samples wa
s also studied at six different pH values (pH 4, 5, 6, 7, 8, 10), The
maximum extraction efficiency was obtained when the pH of urine soluti
ons was adjusted to 7,0, (C) 1998 John Wiley & Sons, Ltd.