[Modification of HLB-HPLC-MS/MS method for the determination of phthalate metabolites in infant urine]

Monitoring infants' exposure to 10 phthalates by measuring their urinary metabolites using a modified high performance liquid chromatography tandemelectrospray ionization mass spectrometry( HPLC-ESI-MS/MS) method.

A total of 50 infants at 0-6 month-old were recruited and their urine samples were collected by commercial available gel diapers. After the urine expression, phthalates were hydrolyzed by β-glucuronidase, cleaned up by HLB cartridge, then these metabolites were measured by HPLC-ESI-MS/MS equipped with a Hypersil Gold Phenyl column. The target compounds were quantified by the stable isotope dilution technique.

The limit of detection( LOD) was 0. 06-0. 16 μg/L with linear ranged 0. 2-500 μg/L. 8 of 10 phthalate metabolites could be detected with > 98% frequencies, from the high to low levels( geometric mean, μg/L) they were Mi BP( 10. 35), MECPP( 5. 13), MBP( 4. 53), MEP( 1. 98), MMP( 1. 69), MEHP( 1. 22), MEHHP( 1. 18) and MEOHP( 0. 99). MBz P and MCHP could be detected in very low frequencies of 28% and 2%, respectively. Formula feeding might be one of the major routes of infant exposure to DEHP( parent compound of MEHP, MEOHP, MEHHP and MECPP) and BBz P( parent compound of MBz P).

The modified HLB-HPLC-MS/MS method can be used for determination of PAEs metabolites in infant urine effectively, and it is valuable for monitoring the infant'exposure risk to PAEs.