基于吸光材料的激光解吸附离子化质谱用于纺织品快速筛查

Rapid Screening of Textiles by Antireflection Laser Desorption Ionization Mass Spectrometry

  • 摘要: 建立了基于微纳吸光材料的激光解吸附离子化质谱法快速检测纺织品中有害物质邻苯二甲酸酯、乙醇胺和己内酰胺。以不锈钢板为基底,利用激光加工技术获得微纳吸光材料,可将紫外激光能量高效转化为热能,实现材料表面待测物的解吸附和离子化,并进行质谱分析。为考察方法的定量能力,采用内标法定量分析邻苯二甲酸二丙酯、邻苯二甲酸二乙酯,结果表明,二者分别在10~200、10~150 μmol/L浓度范围内呈现较好的线性关系。该方法无需繁琐的样品前处理,在1 min内即可完成待测样品的快速质谱分析,且灵敏度高、溶剂消耗少,适用于纺织品中有害物质的快速、高通量筛查。

     

    Abstract: 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.

     

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