The use of chemical derivatization to enhance liquid chromatography/tandem mass spectrometric determination of 1‐hydroxypyrene, a biomarker for polycyclic aromatic hydrocarbons in human urine

Abstract

This article presents an analytical approach that used chemical derivatization to enhance mass spectrometric (MS) response in electrospray ionization (ESI) mode of 1-hydroxypyrene (1-OHP), a commonly used biomarker to monitor human exposure to polycyclic aromatic hydrocarbons (PAHs). The enhancement successfully enabled the desired detection of 50 pg/mL in human urine. The introduction of an MS-friendly dansyl group to 1-OHP enhanced both ionization efficiency in the ESI source and collision-activated dissociation (CAD) in the collision cell. The response increase was estimated to be at least 200-fold, and enabled the reduction of sample size to only 100 microL. The selective MS detection also facilitated a fast (run time 3 min) liquid chromatography (LC) method which successfully resolved the analyte and interferences. The sample processing procedure included enzymatic hydrolysis of glucuronide and sulfate conjugates, liquid-liquid extraction, derivatization with dansyl chloride and a final liquid-liquid extraction to generate clean extracts for LC/MS/MS analysis. This approach has been validated as sensitive, linear (50-1000 pg/mL), accurate and precise for the quantitation of 1-OHP in human urine. This is the first report of using chemical derivatization to enhance MS/MS detection with fast chromatography in the determination of 1-OHP in human urine.

Direct measurement of the glucuronide conjugate of 1-hydroxypyrene in human urine by using liquid chromatography with tandem mass spectrometry

“…On the other hand, the glucuronide is easy to fragment in the collision cell. Further, the sensitivity of the present method which does not require a derivatization step was better than or comparable to those of LC-MS/MS methods with derivatization steps [17,20,21].…”

“…In most cases, the fragmentations, loss of CO (28 Da) from the [M-H] -ion [16,18] and loss of a water molecule from [M+H] + [19] of 1-OHP were monitored as the product ion. The product ions used in the previous studies may have been difficult to fragment in the collision cell because of the highly conjugated and rigid chemical structure of 1-OHP [17]. On the other hand, the glucuronide is easy to fragment in the collision cell.…”

“…1-OHP is a urinary PAH metabolite that has often been used as a biomarker for recent exposure to multiple routes of PAHs. 1-OHP in human urine has been measured with analytical equipments like HPLC with fluorescence detection (HPLC-FL), GC-MS, LC-MS/MS [11][12][13][14][15][16][17][18][19][20][21].…”

“…The hydrolysis step is time-consuming, and its possible incomplete hydrolysis should be taken into consideration [8]. GC-MS methods and some LC-MS/MS methods require a derivatization step in addition to the hydrolysis [15,17,20,21]. Thus, direct measurement of 1-hydroxypyrene-glucuronide (1-OHP-G) would be ideal for the analysis of urine samples.…”

Analysis of steroidal estrogens as pyridine-3-sulfonyl derivatives by liquid chromatography electrospray tandem mass spectrometry

“…2B) shows a series of intense ions that appear to have originated from the E2 moiety. Most notable of these is the prominent ion at m/z 272, which we have assigned to a radical E2 cation produced by the loss of the PS group as a neutral radical from the [ 2 , are apparent in the product ion spectra of the dansyl derivatives of some phenolic compounds [34,35] and for some sulfonamides in the negative ion mode [36]. The relatively minor peak at m/z 79 is assigned to the radical pyridinium ion formed by homolytic cleavage of the bond between the protonated pyridine ring and the sulfonyl group.…”