Procedure for increasing the detection responses of estrogens in LC-MS based on introduction of a nitrobenzene moiety followed by electron capture atmospheric pressure chemical ionization.

A practical procedure for determining estrogens in biological fluids has been studied using liquid chromatography-electron capture atmospheric pressure chemical ionization-mass spectrometry combined with derivatization. Among the commercially available reagents (4-nitrobenzoyl chloride, 2,4-dinitrofluorobenzene, 4-nitrobenzenesulfonyl chloride and 4-nitrobenzyl bromide), 4-nitrobenzenesulfonyl chloride was of the most practical use; it rapidly and quantitatively reacted with estrogens and increased the detection responses by 8-23 times. The derivatization method allowed the reproducible and accurate quantification of serum and urine estrone and estradiol of a pregnant woman, which is useful for diagnosis of the fetoplacental function, with small amounts (10 mul) of sample and a simple pretreatment procedure. Tatsuya Higashiis Associate Professor of the Laboratory of Clinical Analytical Sciences (Professor Kazutake Shimada's research group) at the Graduate School of Natural Science and Technology of Kanazawa University. He received the Japan Society for Analytical Chemistry Award for Young Scientists in 2003 and the Pharmaceutical Society of Japan Award for Young Scientists in 2006. His current research interests are the development of methods for increasing sensitivity in LC-MS to detect and characterize trace amounts of biologically active steroids, such as estrogens, androgens and neuroactive steroids.