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Direct determination of estriol 3‐ and 16‐glucuronides in pregnancy urine by column‐switching liquid chromatography with electrospray tandem mass spectrometry
Author(s) -
Yang Yoon Jung,
Lee Jeongae,
Choi Man Ho,
Chung Bong Chul
Publication year - 2003
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.215
Subject(s) - chemistry , chromatography , estriol , electrospray ionization , urine , liquid chromatography–mass spectrometry , detection limit , tandem mass spectrometry , mass spectrometry , biochemistry , hormone
Abstract Using column‐switching liquid chromatography/tandem mass spectrometry (LC‐MS/MS), we developed an improved analytical method of urinary estriol glucuronides. This new method is derived predominantly from maternal and fetal precursors in pregnancy. We used in the following procedure: first, we filtered urine samples with a membrane filter. Next, we directly injected the 50 µL aliquot of urine samples onto a pre‐column. Then, after activating the column‐switching valve, we backflushed the loaded samples onto the C 18 analytical column. Urine samples can be assayed within 20 min without any sample preparation steps. We monitored separated estriol glucuronides by negative electrospray ionization (ESI) and selected‐reaction monitoring (SRM). The calibration range of estriol‐3‐glucuronide (E3‐3G) and estriol‐16‐glucuronide (E3‐16G) was 0.1–20 µg/mL and the linearity of the method was 0.9984 for E3‐3G and 0.9987 for E3‐16G. The limits of detection at a signal‐to‐noise (S/N) ratio of 3 were 10 ng/mL (E3‐3G) and 5 ng/mL (E3‐16G). The analytical recovery was over 85% and, in general, inter‐day and intra‐day variability for precision and accuracy were less than 10%. When applied to a pregnancy urine sample to biomedical monitoring of the function of the maternal/fetal unit, the proposed method allowed rapid and sensitive screening for the detection of E3‐3G and E3‐16G. Copyright© 2003 John Wiley & Sons, Ltd.