Direct analysis of benzo[ a ]pyrene metabolites with strong overlapping in both the spectral and lifetime domains

ALFARHANI, BASSAM; AL-TAMEEMI, MAHA; GOICOECHEA, HECTOR C.; BARBOSA, FERNANDO; CAMPIGLIA, ANDRES D.

MICROCHEMICAL JOURNAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2018 vol. 137 p. 51 - 61

0026-265X

he ultimate goal of the present study is to develop screening methodology for the urine analysisof metabolites of polycyclic aromatic hydrocarbons. The investigated approach is based onsurface matrix fluorescence spectroscopy, where octadecyl silica membranes serve the dualpurpose of metabolite extraction and solid substrate for fluorescence measurements. One of themain challenges faced by this approach is the interference of concomitants in the sample matrix.The present study focuses on three metabolites with strong spectral and lifetime overlapping,namely benzo[a]pyrene-trans-9,10-dihydrodiol, benzo[a]pyrene-r-7,t-8,c-9-tetrahydrotriol andbenzo[a]pyrene-r-7,t-8,c-9,c-10-tetrahydrotetrol. As an attempt to improve spectral and lifetimereoslution, time-resolved excitation emission matrices are recorded at 77 K with the aid of acryogenic fiber optic probe and laser-based instrumentation. In comparison to conventionalspectrofluorimeters, the use of laser-based instrumentation improves the limits of detection byapproximately two-orders of magnitude. The fiber optic probe facilitates the collection of timeresolvedexcitation emission matrices for the detection of the three metabolites at the pg mL-1concentration level. Their accurate determination in urine samples of unknwon composition isonly possible with the aid of unfolded-partial least squares/residual tri-linearization. Thisalgorithm demonstrated to be well-equipped to handle strong overlapping in both the spectral