Background Automotive repair workers are exposed to a wide variety of volatile organic compounds (VOCs) during painting operations, which poses significant health risks. Biomonitoring can directly reflect the internal body burden of these compounds. Therefore, it is essential to develop an analytical method for simultaneous determination of VOCs in the urine of automotive spray painting workers.

Objective To establish a static headspace gas chromatography-mass spectrometry (GC-MS) method for simultaneously determining 22 VOCs in the urine of spray painting workers in automotive repair enterprises.

Methods An automatic headspace sampler was used for the pretreatment of urine samples. The headspace conditions as well as the chromatographic and mass spectrometric conditions of static headspace GC-MS were optimized. The separation of 22 VOCs was achieved by optimizing the temperature program. Sensitivity was enhanced by optimizing the quantitative ions. The signal response of VOCs was improved by optimizing the headspace equilibrium temperature, equilibrium time, and the amount of inorganic salt added. The method's detection limit, lower limit of quantification, accuracy, precision, and stability were tested using blank urine samples spiked with standards. Additionally, the method was applied to examine 40 urine samples collected from painting workers in automotive repair enterprises in Tianjin.

Results In this study, the headspace equilibrium temperature was set at 80 ℃, the equilibrium time was 30 min, and the salt addition amount was 2.0 g. A DB-624ms chromatographic column was selected for the separation of 22 VOCs. The initial temperature of heating program was 50 ℃, maintained for 15 min, and then increased to 85 ℃ at a heating rate of 10 ℃·min⁻¹ for 10 min, followed by increasing to 90 ℃ at a heating rate of 5 ℃·min⁻¹ for 20 min. The single ion monitoring (SIM) mode was chosen for the quantitative analysis of the 22 VOCs. The method demonstrated good linearity for determining 22 target analytes in the urine of spray painting workers, with correlation coefficients all above 0.990. The lower limits of quantification (LOQ) for the components ranged from 0.4 to 3.8 μg·L⁻¹. The spiked recovery rates of the samples were between 80.1% and 112.1%, and the relative standard deviations (RSD) ranged from 1.5% to 9.7%. All target analytes could be stored at 4 ℃ for 5 d and at −20 ℃ for 7 d. This method was applied to evaluate urine samples from 40 spray painting workers in automotive repair enterprises in Tianjin. The positive rate of butyl acetate was 37.5%. The positive rate of xylene was 32.5%. The positive rate of toluene was 30.0%. The positive rate of isopropanol was 25.0%. The concentration range of the detected substances was from <lower limit of quantification to 60.56 µg·L⁻¹.

Conclusion The established simultaneous determination protocol of 22 VOCs by static headspace- GC-MS is characterized by its simplicity, high sensitivity, excellent selectivity, and high accuracy. It is suitable for urine samples of spray painting workers in automotive repair industry.