Objective In response to the growing concern over the potential health and environmental risks posed by dichlorophen residues in leather and textile products, this study established an analytical method based on ultrasonic extraction coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The method was developed to enable sensitive and reliable determination of dichlorophen in complex matrices. Furthermore, the applicability of this method for product quality safety risk monitoring was evaluated through interlaboratory validation and the analysis of real-world samples, aiming to provide technical support for regulatory compliance and industrial upgrading.

Methods The optimal analytical conditions were determined through the systematic optimization of sample pretreatment conditions (extraction method, solvent type and volume, extraction temperature and time) and instrumental parameters (mobile phase composition and flow rate, mass spectrometric ionization mode and monitored ion pairs). Specifically, the sample was accurately weighed, followed the addition of 10 mL of methanol for thorough saturation, and the ultrasonic extraction was then performed in a 60 ℃ water bath for 50 min. After cooling to room temperature, the extract was purified through a 0.22 μm organic filter membrane. Chromatographic separation was carried out on a C18 column with isocratic elution using acetonitrile-water as the mobile phase. Mass spectrometric detection was performed in electrospray negative ion mode (ESI⁻) under multiple reaction monitoring (MRM) mode, and quantification was achieved by the external standard method. The selection of ultrasonic extraction over conventional methods was based on its higher extraction efficiency and lower solvent consumption. The optimization process involved univariate experiments to identify the most influential factors, ensuring robustness and reproducibility.

Results Under the optimized conditions, dichlorophen showed a good linear relationship in the concentration range of 5-1000 μg/L, with a correlation coefficient (R²) of 0.999 9. The wide linear range indicates the method’s suitability for both trace-level and relatively high-concentration analyses. The limit of detection (LOD) was calculated as 0.05 mg/kg, based on a signal-to-noise ratio of 3 times the background. This low LOD ensures the method’s capability to detect dichlorophen residues at levels far below the strictest regulatory limits, such as those specified in OEKO-TEX Standard 100. Recovery tests were performed using blank matrices of leather, artificial leather, and textiles spiked at low, medium, and high concentration levels. The average recoveries of dichlorophen ranged from 92.15% to 111.62%, indicating satisfactory accuracy of the method. The relative standard deviations (RSDs) obtained from eight parallel measurements were between 2.83% and 7.61%, demonstrating good precision. The method was further validated through interlaboratory comparison, and the results exhibited good repeatability across different laboratories, confirming its robustness and transferability.

Conclusions This method features simple pretreatment steps, low consumption of organic solvents, high sensitivity, and good reproducibility. It can effectively eliminate the interference from complex matrices, meeting the requirements for rapid qualitative and quantitative determination of dichlorophen residues in actual samples. The use of methanol as the sole extraction solvent minimizes environmental impact and operational hazards. The method is particularly suitable for routine screening of large batches of leather and textile products, where time efficiency and accuracy are critical. It also provides reliable technical support for quality and safety control, risk early warning, and compliance testing of leather and textile products, demonstrating good potential for wide application and promotion.