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Introduction: Urinary Hippuric acid (HA) and Methylhippuric acid (MHA) are considered reliable biomarkers for monitoring exposure to toluene and xylenes. A simple and robust HPLC method for simultaneous determination of HA and MHA in urine samples was developed and validated as per Internation Conference on Harmonization (ICH) Q2 guidelines. Methods: Mobile phase consisting of two solvents A & B, solvent A was 0.1% TFA in water, and solvent B was 0.1% TFA in acetonitrile. Separation was performed in gradient elution mode and the time program was as follows - Time (min)/%B: 0/20, 4/20, 11/80, 11.1/90, 16/90, 16.1/20, 25/20. The detection wavelength was 205 nm. Results: The limits of detection (LOD) and quantification (LOQ) of HA in urine were 0.3 and 1.0 mg/L, and for MHA were 0.25 mg/L and 1.0 mg/L respectively and the recovery for HA and MHA were 95% and 98.9% respectively. Conclusion: The developed method was successfully applied for the analysis of urine samples.

Aim: Quantification of urinary ortho-cresol (OC) by high pressure liquid chromatography coupled with photodiode array detector. Materials and Methods: Includes acid hydrolysis of urine, liquid–liquid extraction, and chromatography quantification of extracted OC in urine. Results: Limit of detection, limit of quantification, and coefficient of linearity (R2) were 0.18 μg/ml, 0.62 μg/ml, and 0.9998, respectively. Recovery % of method ranged from 92%, 97%, and 100%. For intraday and interday precision coefficient of variation was 0.41%, 0.64%, and 0.89%, 0.86% for urine samples spiked with OC standards final concentration of 0.25 μg/ml and 0.7 μg/ml, respectively. Results (mean ± standard deviation) of exposed and unexposed real urine samples analyzed for OC with this method were 0.92 ± 0.76 and 0.40 ± 0.20 μg/ml, respectively. Statistical analysis of results showed significant (P ≤ 0.001) difference between urinary OC among exposed and unexposed subjects. Conclusion: The present work describes precise, easy, and less time consuming method for estimation of OC in urine of population exposed to toluene. It can be used as a promising tool for biomonitoring of population exposed to toluene.

Aim: This study aimed to establish liquid–liquid extraction (LLE) for estimation of hippuric acid (HA) in urine as a biomarker of the toluene exposure by high-performance liquid chromatography equipped with photodiode array detector (HPLC-PDAD). Method: HA in urine was extracted by LLE and determined by HPLC-PDAD. The operating conditions with HPLC were ODS-2 hypersil column (250 mm × 4.6 mm, 5 μm), 0.1% trifluoro acetic acid (TFA) in acetonitrile and 0.1% TFA in water as mobile phase, 1 ml/min flow rate, and wavelength of 205 nm. The validity of the present method was tested by the estimation of HA in urine samples, collected from toluene-exposed (shoe workers) and unexposed or control subjects. Results: Binary gradient system was used to achieve optimum separation. The analytical curve prepared for HA in aqueous solution in the range of 0.5–10 μg/ml showed determination coefficient value (R2) 0.998. Limit of detection and quantification (LOQ) were 0.46 and 1.53 μg/ml, respectively. The coefficients of variance for intraday precision were 1.4% for HA standard (5 μg/ml) and 1.1% for pooled urine, whereas inter-day precision values were 3.2% and 4.9% for HA standard and pooled urine, respectively. Method recovery obtained was 96%–120% for HA solutions containing 2, 3, and 5 μg/ml, demonstrating that precision and recovery of method were satisfactory. Compared to unexposed group, exposed group had significantly more HA. It was found significantly (P < 0.05) higher in urine of exposed workers (32.52 ± 10.91) than unexposed group (16.21 ± 10.14). Conclusion: Sample preparation by LLE is simple and cost-effective for the determination of HA as a biomarker of toluene exposure by HPLC-PDAD. It can be used to detect HA in urine for population exposed to toluene.

Background: Combustion of traditional biomass fuels and coal has been found to be associated with exposure to particulates and volatile organic compounds (VOCs) and cause a series of adverse health effects. Characterization-quantification of such exposure achieved so far is not optimum, and establishment of a protective mechanism with proven efficacy is the urgent need. Methods: The present study was planned to characterize exposure from fuel during cooking in a village of India and understand the effect of using intervention measure. In this study, exposure to different pollutants was examined by personal monitoring in different cooking arrangements with traditional and modified oven. Results: It is observed that level of the pollutants has lessened by several folds while cooking with modified oven in comparison to unmodified oven. Such change of pollutants levels with the use of modified oven was found to be statistically significant in cases of benzene (P < 0.001), toluene (P < 0.01), and particulates (P < 0.0001). Conclusions: This study highlights the exposure from indoor air pollution during cooking and promotes use of low-cost protective mechanisms to curb resulting human health adversities. This study also calls for concerted awareness generation activity among the rural population (especially women) regarding adverse health effect of cooking fuels and protective effect of installed mechanisms.