Determination of 1-hydroxypyrene in human urine by high-performance liquid chromatography with fluorescence detection using a deuterated internal standard

Unearth the Luminescence Potential of Metal-Organic Frameworks: Adopting a Feasible Strategy to Fabricate One Ratiometric Fluorescence Sensor for Monitoring Both 1-Hydroxypyrene and Cu2

In this work, a novel luminescent hybrid material with double emission centers (Eu(TTA)_0.2@9-1-UMOF) is successfully prepared, adopting a feasible design strategy. Initially, the second ligand 1,2,4-benzenetricarboxylic acid (H₃BTC) is encapsulated based on a solid solution approach, which effectively improves the ligand-based emission intensity of the original LMOF and provides functional sites for introducing the second luminescent center; then, Eu³⁺ as the red emission source is loaded into the frameworks through a coordination post-synthetic modification method; finally, to balance the emission intensity at 613 nm (Eu³⁺) and 465 nm (1,4-naphthalenedicarboxylic acid (H₂NDC)), 2-thenoyltrifluoroacetone (TTA) as a powerful antenna is introduced. Given the outstanding luminescence properties and structural stability of Eu(TTA)_0.2@9-1-UMOF, it is further developed as a ratiometric sensor for detecting 1-hydroxypyrene (1-HP, the biomarker of polycyclic aromatic hydrocarbons (PAHs)) and Cu²⁺, which promotes the pre-diagnosis of human health. Notably, Eu(TTA)_0.2@9-1-UMOF exhibits excellent selective recognition ability for both 1-HP and Cu²⁺ with high sensitivity (LOD = 4.06 × 10^-6 mg/mL, 3.85 × 10^-7 mol/L, respectively) and fast response speed. In addition, Eu(TTA)_0.2@9-1-UMOF as a fluorescent probe shows great potential for the determination of 1-HP and Cu²⁺ in actual samples. More importantly, this work widens the road for the development of dual/multiple LMOF-based sensors for analytical applications.

A review of the analysis of biomarkers of exposure to tobacco and vaping products

Quantification of exposure to different chemicals from both combustible cigarettes and vaping products is important in providing information on the potential health risks of these products. To assess the exposure to tobacco products, biomarkers of exposure (BOEs) are measured in a variety of biological matrices. In this review paper, current knowledge on analytical methods applied to the analysis of biomarkers of exposure to tobacco products is discussed. Numerous sample preparation techniques are available for the extraction and sample clean up for the analysis of BOEs to tobacco and nicotine delivery products. Many tobacco products-related exposure biomarkers have been analyzed using different instrumental techniques, the most common techniques being gas and liquid chromatography coupled with mass spectrometry (GC-MS, GC-MS/MS and LC-MS/MS). To assess exposure to emerging tobacco products and study exposure in dual tobacco users, the list of biomarkers analyzed in urine samples has been expanded. Therefore, the current state of the literature can be used in preparing a preferred list of biomarkers based on the aim of each study. The information summarized in this review is expected to be a handy tool for researchers involved in studying exposures to tobacco products, as well as in risk assessment of biomarkers of exposure to vaping products.

Sensitive and selective urinary 1-hydroxypyrene detection by dinuclear terbium-sulfonylcalixarene complex

Conveniently synthesized sulfonylcalixarene-based dinuclear terbium luminescent sensor exhibits quick response, high sensitivity, and specific selectivity for urinary 1-hydroxypyrene detection.

A pyrene-involved luminescent MOF for monitoring 1-hydroxypyrene, a biomarker for human intoxication of PAH carcinogens

A robust pyrene-involved MOF is developed as a luminescent platform for sensitive detection of 1-hydroxypyrene, a human intoxication biomarker of PAH carcinogens, by utilizing the efficient host–guest π–π charge transfer interactions.

Biomarkers of exposure to new and emerging tobacco delivery products

Accurate and reliable measurements of exposure to tobacco products are essential for identifying and confirming patterns of tobacco product use and for assessing their potential biological effects in both human populations and experimental systems. Due to the introduction of new tobacco-derived products and the development of novel ways to modify and use conventional tobacco products, precise and specific assessments of exposure to tobacco are now more important than ever. Biomarkers that were developed and validated to measure exposure to cigarettes are being evaluated to assess their use for measuring exposure to these new products. Here, we review current methods for measuring exposure to new and emerging tobacco products, such as electronic cigarettes, little cigars, water pipes, and cigarillos. Rigorously validated biomarkers specific to these new products have not yet been identified. Here, we discuss the strengths and limitations of current approaches, including whether they provide reliable exposure estimates for new and emerging products. We provide specific guidance for choosing practical and economical biomarkers for different study designs and experimental conditions. Our goal is to help both new and experienced investigators measure exposure to tobacco products accurately and avoid common experimental errors. With the identification of the capacity gaps in biomarker research on new and emerging tobacco products, we hope to provide researchers, policymakers, and funding agencies with a clear action plan for conducting and promoting research on the patterns of use and health effects of these products.

Identification and characterization of oxidative metabolites of 1-chloropyrene

Polycyclic aromatic hydrocarbons (PAHs) and chlorinated PAHs (ClPAHs) are ubiquitous contaminants that bind to the aryl hydrocarbon receptor (AhR) and exhibit mutagenic potential. It is difficult to monitor human exposure levels to ClPAHs because the exposure routes are complicated, and environmental concentrations are not always correlated with the levels of PAHs. Urinary PAH metabolites are useful biomarkers for evaluating PAH exposure, and ClPAH metabolites may therefore contribute to the estimation of ClPAH exposure. One of the most abundant ClPAHs present in the environment is 1-chloropyrene (ClPyr), and urinary ClPyr metabolites have the potential to be good biomarkers to evaluate the level of exposure to ClPAHs. Since the metabolic pathways involving ClPAHs are still undetermined, we investigated the effect of human cytochrome P450 enzymes on ClPyr and identified three oxidative metabolites by liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance. We found that ClPyr was metabolized most efficiently by the P450 1A1 enzyme, followed by the 1B1 and 1A2 enzymes. Similar to ClPyr, these metabolites were shown to have agonist activity for the human AhR. We detected these metabolites when ClPyr reacted with a pooled human liver S9 fraction as well as in human urine samples. These results suggest that the metabolites may be used as biomarkers to evaluate the extent of exposure to ClPAHs.

A gold nanoparticle-based colorimetric probe for rapid detection of 1-hydroxypyrene in urine

Direct and rapid detection of 1-hydroxypyrene (1-OHP) is of great importance owing to its high carcinogenicity, teratogenicity and toxicity.

[Pharmaceutical analysis of chemicals related with daily life products for safe and secure]

An association between exposure to trace hazardous chemicals such as endocrine disrupting chemicals and an increased incidence of human endocrine disease might be continued to study. The accurate and sensitive analytical methods for determination of various chemicals in human biospecimen such as urine, blood and breast milk have been studied by techniques including chromatography. In order to obtain the safe and secure life, the pharmaceutical analytical approaches might be applicable with the hopes of realizing scientific risk assessment of the chemicals derived from daily life products as regulatory sciences.

Urinary 1-hydroxypyrene levels among office workers living in industrial areas

We examined exposure to polycyclic aromatic hydrocarbons (PAHs) among non-smoking office workers in 2 countries living in the vicinity of a coke-oven factory by measuring their levels of urinary 1-OHP, a known metabolite of PAHs. Subjects included 10 non-smoking office workers in Kitakyushu city (Japan) and 20 workers in Thai Nguyen city (Vietnam). Measurement was optimized by using the high-performance liquid chromatography (HPLC) method developed by Jongeneelen et al. This method required only a small amount of urine and had a short incubation time, and its detection limit was very low (0.00448 ng/ml), which was practical and highly sensitive.The median urinary 1-OHP concentration in the Vietnamese subjects (0.417 ng/mg creatinine) was six times as high as that in the Japanese subjects (0.069 ng/mg creatinine) (P < 0.001). However, both concentrations were significantly below the guideline level, below which there is no genotoxic effect, implying a low probability of any adverse health effects.Our measurements from both countries showed higher urinary 1-OHP concentrations than in previous studies from locations without factories, indicating that ambient air pollution from industrial emissions is an important source of PAH exposure. Finally, the urinary 1-OHP concentrations did not correlate with gender or lifestyle factors.

Urinary 1-hydroxypyrene as a biomarker to carcinogenic polycyclic aromatic hydrocarbon exposure

In order to capture the extent of exposure to polycyclic aromatic hydrocarbons (PAHs), various biomarkers have been employed. The biomarkers employed for PAHs include PAHs genetoxic end points in lymphocytes, urinary metabolites, PAH-DNA adducts, and PAH-Protein adducts. Of these, excretory 1-hydroxypyene, a metabolite of pyrene, has been used extensively as a biological monitoring indicator of exposure to PAHs. This study attempts to assess the level of this biomarker in the body fluid of 68 exposed subjects using high performance liquid chromatography HPLC. The subjects screened included auto mechanics, drivers, and fuel attendants. 1-hydroxypyrene was extracted from the urine of the subjects using solid phase extraction method. The HPLC analysis was done in isocratic mode using water:methanol (12:88 v/v) mobile phase. The stationary phase was XBridge C18 (150 × 4.6 mm) 5 μm column. The wavelength was 250 nm at a flow rate of 1.2 mL/min. The oven temperature was 30 ºC and the injection volume was 20 μL. The run time was 3 minutes. The level of urinary 1-hydroxypyrene detected varied for the different categories of occupation studied. About 27% of sampled fuel attendants and 22% of auto mechanics had detectable 1-hydroxypyrene in their urine samples. There was no detectable 1-hydroxypyene in the urine samples of commercial drivers or in the urine samples of students used as controls. The results of this study showed that fuel attendants and auto mechanics have significant exposures to PAHs. So far, there is no established benchmark for level of PAHs in urine, but our findings indicate the possibility of future cancer cases in this population as a result of their occupational exposure. The study was not able to link the level of 1-hydroxypyene with the smoking habits of the subjects.

Exposure to polycyclic aromatic hydrocarbons, arsenic and environmental tobacco smoke, nutrient intake, and oxidative stress in Japanese preschool children

The association between oxidative stress and exposure to environmental chemicals was assessed in a group of Japanese preschool children. The concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG), 1-hydroxypyrene (1-OHP), inorganic arsenic (iAs) and monomethylarsonic acid (MMA), and cotinine in spot urine samples, collected from 134 children (3-6 yrs) from a kindergarten in Kanagawa, Japan, were measured as biomarkers of oxidative stress or exposure to environmental chemicals. For 76 subjects of the 134, intakes of anti-oxidant nutrients (vitamins A, C, and E, manganese, copper, zinc and selenium (Se)) were estimated from a food consumption survey carried out 2-4 weeks after urine sampling and by urine analysis (Se). The median (min-max) creatinine-corrected concentrations of urinary biomarkers were 4.45 (1.98-12.3), 0.127 (0.04-2.41), 4.78 (1.18-12.7), and 0.62 (<0.6-19.0) μg/g cre for 8-OHdG, 1-OHP, iAs+MMA, and cotinine, respectively. Multiple regression analysis was carried out using 8-OHdG concentration as a dependent variable and urinary biomarkers of exposure and Se intake, intakes of vitamins and biological attributes of the subjects as independent variables. To explain 8-OHdG concentrations, intake of vitamin A and age were significant variables with negative coefficients, while 1-OHP concentration had a positive coefficient. These results indicated that oxidative stress of children is affected by chemical exposure at environmental levels, by nutrient intake and by physiological factors in a complex manner. On the other hand, unstable statistical results due to sub-grouping of subject, based on the availability of food consumption data, were found: the present results should further be validated by future studies with suitable research design.

Quantitation of a minor enantiomer of phenanthrene tetraol in human urine: correlations with levels of overall phenanthrene tetraol, benzo[a]pyrene tetraol, and 1-hydroxypyrene

Polycyclic aromatic hydrocarbons (PAH) are well established carcinogens that are likely to play a role in causing some human cancers. One accepted pathway of PAH metabolic activation is the formation of bay region diol epoxides. Some individuals may be particularly susceptible to PAH carcinogenesis because they metabolically activate PAH more effectively than others. We have used the measurement of urinary phenanthrene tetraols (Phe-tetraols) as a biomarker of PAH exposure plus metabolic activation since bay region diol epoxides are hydrolyzed to tetraols. Because of stereoselectivity in Phe metabolism, Phe-(1R,2S,3R,4S)-tetraol (4) results mainly from the bay region diol epoxide pathway, and Phe-(1S,2R,3S,4R)-tetraol (7) is formed mainly from the reverse diol epoxide pathway, not generally associated with carcinogenicity. The latter pathway accounts for more than 95% of human urinary Phe-tetraol. In most previous studies, Phe-tetraol was quantified without enantiomeric resolution, using a relatively rapid and practical method, applicable to large studies. It was not clear, however, whether measurement of overall unresolved Phe-tetraol would accurately represent the bay region diol epoxide metabolic activation pathway. Therefore, in this study we specifically quantified Phe-(1R,2S,3R,4S)-tetraol (4) by supplementing our usual analysis with chiral HPLC separations and using [(13)C(6)]Phe-(1R,2S,3R,4S)-tetraol as internal standard. We then investigated the relationship of urinary levels of 4 to those of Phe-tetraols (4 + 7), quantified without enantiomeric resolution. We applied these methods to urine samples from cigarette smokers and highly PAH-exposed creosote workers. The results were also compared to levels of benzo[a]pyrene-7,8,9,10-tetraol and 1-hydroxypyrene in the same samples. Levels of 4 were highly correlated with those of 4 + 7 (r > 0.9, P < 0.0001) in both types of urine samples. Strong correlations of 4 and 4 + 7 with benzo[a]pyrene-7,8,9,10-tetraol and 1-hydroxypyrene were also observed. The results of this study demonstrate therefore that practical and convenient measurement of overall Phe-tetraols (4 + 7) in human urine, without enantiomeric resolution, is an excellent indicator of PAH exposure and metabolism by the bay region diol epoxide metabolic activation pathway.

Prenatal exposure to phthalate esters and PAHs and birth outcomes

The purpose of this study was to investigate the relationship between the levels of prenatal exposure to phthalate ester and PAHs and birth outcomes among 149 Japanese pregnant women. Urinary concentrations of 9 phthalate ester metabolites, mono methyl phthalate (MMP), mono ethyl phthalate (MEP), mono-n-butyl phthalate (MnBP), mono benzyl phthalate (MBzP), mono-2-ethylhexyl phthalate (MEHP), mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), mono-iso-nonyl phthalate (MINP) and mono-n-octyl phthalate (MnOP) and PAHs metabolite (1-hydroxypyrene, 1-OHP) were analyzed in spot urine samples collected from pregnant women. Correlation analysis and multiple regression analysis were conducted between the concentrations of maternal urinary metabolites and birth outcomes such as birth weight, birth length, head circumference and gestational age. Creatinine-corrected concentration (geometric mean; microg/g cre) was 9.14 (MMP), 9.76 (MEP), 51.6 (MnBP), 5.62 (MBzP), 5.45 (MEHP), 10.6 (MEHHP), 11.3 (MEOHP), 0.031 (MINP), 0.025 (MnOP) and 0.121 (1-OHP). These concentrations are comparable with literature value. The relationships between prenatal exposure to phthalate esters and birth outcomes were not significant. Statistically significant negative correlation was observed between 1-OHP and birth weight, birth length and head circumstances although the correlation was insignificant when only non-smokers were included in multiple regression analysis. In conclusion, we found that prenatal exposure to phthalate esters or PAHs did not affect birth outcomes at the exposure level of the present subjects.

An improved HPLC method with fluorescence detection for the determination of pyrene in rat plasma and its pharmacokinetics

A high-performance liquid chromatographic method with fluorescence detection (HPLC-FLD) for the determination of pyrene in rat plasma was developed and validated. The method used fluorene as internal standard (IS), following a single-step protein precipitation, the analyte and internal standard were separated on a C18 column with a mobile phase containing methanol-water (90:10, v/v) at a flow rate of 1 ml/min. The analytes were detected by using fluorescence detection at an excitation and emission wavelength of 265 and 394 nm, respectively. Two calibration curves were constructed in the range of 2-100 ng/ml and 0.1-5 microg/ml for pyrene with a lower limit of quantitation (LLOQ) of 2 ng/ml. Both intra-day and inter-day precision were less than 6% except at LLOQ, for which the precision was 10.6 and 9.8, respectively. Accuracy ranged from 98.3 to 103.6%, except at LLOQ, for which the accuracy was about 85%. The recovery ranged from 84.7 to 95.0% at the low, medium and high concentrations. The present HPLC-FLD method was rapid, sensitive, and reliable. The method described herein had been successfully applied for the pharmacokinetic studies in female Wistar rats after administration of 10mg equivalent pyrene/kg dose of solution of pyrene and 1mg equivalent pyrene/kg dose of pyrene-loaded nanoparticle.

Cooperativity of cytochrome P450 1A2: interactions of 1,4-phenylene diisocyanide and 1-isopropoxy-4-nitrobenzene

Homotropic cooperativity of 1-alkoxy-4-nitrobenzene substrates and also their heterotropic cooperative binding interactions with the iron ligand 1,4-phenylene diisocyanide (Ph(NC)2) had been demonstrated previously with rabbit cytochrome P450 (P450) 1A2 [G.P. Miller, F.P. Guengerich, Biochemistry 40 (2001) 7262-7272]. Multiphasic kinetics were observed for the binding of Ph(NC)2 to both ferric and ferrous P450 1A2, including relatively slow steps. Ph(NC)2 induced an apparently rapid change in the circular dichroism spectrum, consistent with a structural change, but had no effect on tryptophan fluorescence. Ph(NC)2 binds the P450 iron in both the ferric and ferrous forms; ferric P450 1A2 was reduced rapidly in the absence of added ligands, and the rate was attenuated when Ph(NC)2 was bound. No oxidation products of Ph(NC)2 were detected. Docking studies with a rabbit P450 1A2 homology model based on the published structure of a human P450 1A2.alpha-naphthoflavone (alphaNF) complex indicated adequate room for a complex with either two 1-isopropoxy-4-nitrobenzene molecules or a combination of one 1-isopropoxy-4-nitrobenzene and one Ph(NC)2; in the case of alphaNF no space for an extra ligand was available. The patterns of homotropic cooperativity seen with 1-alkoxy-4-nitrobenzenes (biphasic plots of v vs. S) differ from those seen with polycyclic hydrocarbons (positive cooperativity), suggesting that only with the latter does the ligand interaction produce improved catalysis. Consistent with this view, Ph(NC)2 inhibited the oxidation of 1-isopropoxy-4-nitrobenzene and other substrates.

Cooperativity in oxidation reactions catalyzed by cytochrome P450 1A2: highly cooperative pyrene hydroxylation and multiphasic kinetics of ligand binding

Rabbit liver cytochrome P450 (P450) 1A2 was found to catalyze the 5,6-epoxidation of alpha-naphthoflavone (alphaNF), 1-hydroxylation of pyrene, and the subsequent 6-, 8-, and other hydroxylations of 1-hydroxy (OH) pyrene. Plots of steady-state rates of product formation versus substrate concentration were hyperbolic for alphaNF epoxidation but highly cooperative (Hill n coefficients of 2-4) for pyrene and 1-OH pyrene hydroxylation. When any of the three substrates (alphaNF, pyrene, 1-OH pyrene) were mixed with ferric P450 1A2 using stopped-flow methods, the changes in the heme Soret spectra were relatively slow and multiphasic. Changes in the fluorescence of all of the substrates were much faster, consistent with rapid initial binding to P450 1A2 in a manner that does not change the heme spectrum. For binding of pyrene to ferrous P450 1A2, the course of the spectra revealed sequential changes in opposite directions, consistent with P450 1A2 being involved in a series of transitions to explain the kinetic multiphasicity as opposed to multiple, slowly interconverting populations of enzyme undergoing the same event at different rates. Models of rabbit P450 1A2 based on a published crystal structure of a human P450 1A2-alphaNF complex show active site space for only one alphaNF or for two pyrenes. The spectral changes observed for binding and hydroxylation of pyrene and 1-OH pyrene could be fit to a kinetic model in which hydroxylation occurs only when two substrates are bound. Elements of this mechanism may be relevant to other cases of P450 cooperativity.

Identification and Quantification of 1-Nitropyrene Metabolites in Human Urine as a Proposed Biomarker for Exposure to Diesel Exhaust

1-nitropyrene (1-NP) is one of the most abundant nitrated polycyclic aromatic hydrocarbons (NPAHs) in diesel exhaust particulate matter (DEP) and is a main contributor of direct-acting mutagenicity in DEP. Therefore, the metabolites of 1-NP are expected to be a biomarker for assessment of exposure to DEP. In this study, a highly specific and sensitive analytical method using liquid chromatography with tandem mass spectrometry (LC-MS/MS) was developed to determine urinary 1-NP metabolites. After enzymatic hydrolysis of the conjugated metabolites, the analytes were selectively extracted from the urine matrix with blue rayon. The eluate from the rayon was further purified on an acidic alumina cartridge. Hydroxy-N-acetyl- 1-aminopyrenes (6- and 8-OHNAAP) and hydroxy-1-nitropyrenes (3-, 6-, and 8-OHNP) in human urine were identified by their retention times and MS/MS spectra and quantified by using deuterated internal standards. 1-NP metabolites were quantified in urine from all healthy, nonoccupationally exposed subjects. 6-OHNAAP, 8-OHNAAP, 6-OHNP, and 8-OHNP (means of 117, 109, 203, and 137 pmol/mol creatinine, respectively) were the most abundant isomers in human urine. This report is the first to demonstrate the presence of OHNAAPs and OHNPs in human urine, in agreement with previous in vivo and in vitro studies that predicted that these metabolites should be excreted into human urine. This method for determining urinary 1-NP metabolites should be useful for the surveillance of exposure to NPAHs and DEP and will facilitate the study of cancer risk associated with these exposures.

Inhalation and dietary exposure to polycyclic aromatic hydrocarbons and urinary 1-hydroxypyrene in non-smoking university students

OBJECTIVE

To examine which exposure pathway, dietary or inhalation, contribute more to the exposure to, and/or internal dose of, polycyclic aromatic hydrocarbons (PAHs) of non-smoking Japanese.

METHODS

Duplicated diet, personal air samples and 24-h urine were collected from 14 non-smoking male university students without occupational exposure and the concentrations of PAHs in diet and air and that of 1-hydroxypyrene (1-OHP) in urine were measured with HPLC-fluorescence detector.

RESULTS

Daily dietary exposure contributed more than 90% of the total (diet + inhalation) daily exposure level for pyrene (diet/inhalation: 757/1.2 ng/day), benzo[k]fluoranthene (25/1.7 ng/day) and benzo[a]pyrene (91/2.1 ng/day). Urinary excretion of 1-OHP (median: 37 ng/day) was statistically significantly correlated only with dietary PAHs exposure level but not with inhalation.

CONCLUSION

Countermeasures to lower PAHs levels in atmosphere has been successful in Japan and more attention should be directed to dietary exposure to PAHs for reducing cancer risk in general population.

Simultaneous determination of urinary hydroxylated metabolites of naphthalene, fluorene, phenanthrene, fluoranthene and pyrene as multiple biomarkers of exposure to polycyclic aromatic hydrocarbons

A method is presented for determining monohydroxy polycyclic aromatic hydrocarbons (OHPAHs) having 2-, 3- and 4-rings in human urine by using high-performance liquid chromatography with fluorescence detection. A urine sample containing conjugates of OHPAHs was hydrolysed in the presence of beta-glucuronidase/aryl sulfatase and the solution was cleaned up with a solid-phase extraction (C(18) and silica). Eight OHPAHs, namely 1- and 2-hydroxynaphthalenes, 2-hydroxyfluorene, 2-, 3- and 4-hydroxyphenanthrenes, 3-hydroxyfluoranthene and 1-hydroxypyrene, were separated and 1- and 9-hydroxyphenanthrenes co-eluted on an alkylamide-type reversed-phase column with fluorimetric detection. The urinary concentrations of OHPAHs were quantified by using deuterated 1-hydoxypyrene as an internal standard. The method showed good repeatability for inter- and intra-day precisions as well as good linearity of calibration curves (r (2) ranged from 0.996 to 0.999). The limits of detection (S/N=3) were in the range from 2.3 fmol to 2.2 pmol per injection. This method was successfully applied to urine samples from non-smoking taxi drivers, traffic policemen and rural villagers of Chiang Mai, Thailand. The results showed higher urinary concentrations of OHPAHs in rural villagers, consistent with higher respiratory exposure to PAHs.

Evaluation of estrogenic activities of hydroxylated polycyclic aromatic hydrocarbons in cigarette smoke condensate

Estrogenic activities of cigarette smoke condensates obtained from the extraction of particulate matters from mainstream and sidestream cigarette smoke with benzene/ethanol were evaluated by using a yeast two-hybrid assay system expressing human estrogen receptor alpha (hERalpha). To identify the constituents of the cigarette smoke condensate which are responsible for the estrogenic activity, the condensate was fractionated into eleven fractions by liquid-liquid extractions. Among these fractions, the neutral fractions of mainstream and sidestream smoke showed the strongest estrogen receptor-mediated activity by the yeast two-hybrid assay. Then the neutral fractions were fractionated by medium-pressure liquid chromatography with silica gel column. In the fractions that showed strong estrogenic activity, 2-hydroxyfluorene (2-OHFle), 2- and 3-hydroxyphenanthrene (2- and 3-OHPhe), 1-hydroxypyrene (1-OHPyr) and n-propyl-p-hydroxybenzoate (n-PHB) were identified by LC- and GC-MS and HPLC with fluorescence detection. 2-OHFle, 2-OHPhe and n-PHB exhibited estrogenic activity, whereas weak activity was observed with 3-OHPhe and 1-OHPyr. Several other hydroxylated polycyclic aromatic hydrocarbons having no activity were also identified. This is a first study to identify estrogenic hydroxylated PAHs in cigarette smoke condensate. The present findings points out the necessity for detailed investigation of exposure to aerosols containing apparently estrogenic compounds.

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

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.

Improved Method for Determination of 1-Hydroxypyrene in Human Urine

We have developed an improved method for the analysis of human urine for 1-hydroxypyrene (1-HOP), an accepted biomarker of polycyclic aromatic hydrocarbon uptake. This method takes advantage of commercially available 96-well format devices, which expedite sample preparation before quantitation by HPLC with fluorescence detection. In addition to improved speed of analysis, which is critical for the application of this assay in molecular epidemiology studies, the method described here uses an internal standard, 1-hydroxybenz[a]anthracene, improved sample preparation methods, and optimized HPLC and fluorescence detection conditions. The resulting method for analysis of 1-HOP is sensitive (detection limit, 0.05 pmol/mL urine), accurate (as determined by known addition of 1-HOP to urine), and precise [relative SD (RSD), 4.13%]. A longitudinal study of 1-HOP levels in the urine of 10 nonsmokers showed considerable day-to-day (mean RSD, 55.1 %) and week-to-week (mean RSD, 38.2 %) intra-individual variation, indicating the necessity for multiple sampling in studies concerned with relatively small differences in polycyclic aromatic hydrocarbon exposure.

Determination of 1-hydroxypyrene in children urine using column-switching liquid chromatography and fluorescence detection

This study developed an acid hydrolysis method instead of using enzyme extraction, equipped with column-switching system for the pretreatment of samples, in the determination of 1-hydroxypyrene in the urine from children and pyrene in airborne particulates. We collected both types of samples from areas near a petrochemical industry and rural areas as reference. Samples were first treated with acid hydrolysis and followed by solvent extraction prior to being injected into the separation system for the determination with high performance liquid chromatography and fluorescence. A column-switching system was on-line with a C18 separation column to remove matrix interference and obtain a stable baseline of the chromatogram. The eluent used to separate the 1-hydroxypyrene was 60% (v/v) aqueous acetonitrile solution. A fluorescence detector was used to monitor 1-hydroxypyrene at lambdaex = 348 nm and lambdaem = 388 nm, and pyrene at lambdaex = 331 nm and lambdaem = 390 nm. Both calibration graphs were linear with very good correlation coefficients (r > 0.999) and the detection limits were ca. 2pg (5ng/l). Results showed that there was a significant association between 1-hydroxypyrene levels in urine specimens and pyrene levels in airborne particulate samples (r = 0.68, P < 0.05). The average levels of pyrene in the particulates (0.18 versus 0.09ng/m3) and of 1-hydroxypyrene in urine specimens (155.9 versus 110.2ng/g creatinine) were higher for the petrochemical area than for the rural area. This method is stable and sensitive for measuring polycyclic aromatic hydrocarbons in environmental samples.

Method for determining monohydroxybenzo[a]pyrene isomers using column-switching high-performance liquid chromatography

A method for determining monohydroxybenzo[a]pyrene (OHBaP) isomers using column-switching high-performance liquid chromatography with fluorescence detection was developed. Eleven of 12 isomers of OHBaP (all except 6-OHBaP) were separated on an alkylamide-type reversed-phase column and, via column-switching, on a beta-cyclodextrin-bonded silica gel column. The detection limits for the OHBaPs were in the range 0.3-8 pg/injection (S/N=3). By using this method, 1-, 3-, and 9-OHBaPs were identified as major metabolites of benzo[a]pyrene in vitro by human recombinant p450 1A1. The method was used to determine OHBaPs in the urine of a nonsmoker subject. After enzymatic hydrolysis of the conjugated metabolites by beta-glucuronidase/aryl sulfatase, the analytes were selectively adsorbed on blue rayon (a cellulose-supported copper phthalocyanine) from the urine matrix. Methanol as the eluting solvent from the rayon gave the best recoveries of OHBaPs and 1-hydroxypyrene (1-OHP) in the range of 91-103%, which was superior to that of the solid-phase extraction method. 1-OHP, a well-known biomarker of the exposure to polycyclic aromatic hydrocarbons, was simultaneously analyzed. Intra- and interday accuracy values for the determination of 3-OHBaP in 200 ml of urine were 95.5 and 100.9%, and those for 1-OHP were 96.4 and 103.6%, respectively. The intra- and interday precision values were 3.9 and 2.4% for 3-OHBaP and 2.4 and 3.2% for 1-OHP, respectively. In 11 kinds of isomers, only 3-OHBaP was detected in the human urine. Urinary concentration of 3-OHBaP was quantified at 0.5 ng/g creatinine concentration and the 3-OHBaP/1-OHP ratio was approximately 1/130.