Determination of isotopically labelled monoesterphthalates in urine by high performance liquid chromatography-mass spectrometry.
A method of analysis for monoesters of phthalic acid ('monoesterphthalates') in human urine has been developed. The method was needed to determine the hydrolysis and excretion efficiency of isotopically-labelled phthalate diesters ('phthalates') when they were fed to volunteers as part of a biomarker study to estimate total exposure to phthalates. The targeted substances were 13C-monobutylphthalate (MBP), 2H4-monobutylphthalate (MBP), 2H4-monobenzylphthalate (MBeP), 13C-monocyclohexylphthalate (MCHP), 13C-monoethylhexylphthalate (MEHP), and 13C-monoisodecylphthalate (MIDP). The monoesters in urine were deconjugated enzymatically, extracted into solvent, and then determined by high performance liquid chromatography-mass spectrometry (LC-MS) using atmospheric pressure chemical ionisation in the negative ion mode. The limits of determination were 10 ng ml(-1) for MBP, MCHP, MBeP and MEHP, and 40 ng ml(-1) for MIDP. The recovery from urine spiked at 100 ng ml(-1) was in the range from 70 to 85% except for MIDP which was lower at 55%. The between-batch reproducibility of the analysis was in the range 8 to 17% (n = 6 batches on separate days).
Anderson
Warwick A C
WA
Department for Environment, Food and Rural Affairs, Sand Hutton, York, UK.
Barnes
Karen A
KA
Castle
Laurence
L
Damant
Andrew P
AP
Scotter
Michael J
MJ
D015415:Biomarkers / Q000652:urine; D002853:Chromatography, Liquid; D006801:Humans; D007553:Isotope Labeling; D010795:Phthalic Acids / Q000652:urine*; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis
D015415:Biomarkers; D010795:Phthalic Acids; C032279:phthalic acid