Rapid Screening of Textiles by Antireflection Laser Desorption Ionization Mass Spectrometry

A rapid method for the screening of hazardous chemicals in textiles was developed using antireflection-laser desorption ionization mass spectrometry (AR-LDI-MS). An antireflection material was used to replace the small-molecule matrix used in traditional matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS). This material has quasi-periodical array structure on its surface, which is fabricated using one-step direct writing with ultrafast laser on a stainless steel plate. Light can be trapped after multiple reflections inside the structure, accompanied by the excitation of surface plasmon resonance, which converts light energy to heat. With over 90% UV laser energy converted to heat, this material allows thermal desorption and ionization of target analyte on the surface. Since no matrix is used, no interference at low m/z area is found in AR-LDI-MS analysis, which allows the detection of analytes of low molecular weights. The antireflection material is also durable and reusable after careful cleaning. In the screening process, the analytes were extracted and transferred to the antireflection surface, followed by LDI-MS analysis. The pulsed UV laser had a pulse frequency of 1 kHz and a wavelength of 355 nm, which provided the energy for sample molecules' desorption and ionization. A high voltage of 2 500 V was applied between the antireflection material and the mass spectrometer capillary to guide the ions into the mass spectrometer. The whole process could be completed in less than 1 min, avoiding time-consuming sample pretreatment and excessive solvent consumption compared with traditional chromatography or chromatography-mass spectrometry methods. Six hazardous chemicals in textiles were analyzed including phthalate esters, caprolactam, diethanolamine and triethanolamine. The limits of detection (LODs) of phthalate esters (1 mg/kg) and caprolactam (1 mg/kg) were comparable with traditional methods, but the LODs of diethanolamine (60 mg/kg) and triethanolamine (50 mg/kg) were relatively high. Quantitative analysis of phthalate esters was also performed using internal standards. Six textile samples purchased from local supermarket and internet were used for the screening of hazardous chemicals mentioned before by the method, and only caprolactam was detected in one sample. AR-LDI-MS is suitable for the rapid and high-throughput screening of textiles, and it can be also potentially used for the screening of other consumer goods, like food, cosmetics and detergents. Detection of chemical residues on the human skin or object surface may also be a possible application. © 2021, Editorial Board of Journal of Chinese Mass Spectrometry Society. All right reserved.