High-throughput screening of phthalate-containing objects in the kindergartens by ambient mass spectrometry

High-throughput screening of plastic products in children's living environment is necessary to identify phthalate-containing objects for the concern of public health and safety. A novel strategy of probe collecting technique combined with ambient mass spectrometry was developed to carry out the large-scale sample analysis. Analytes from the surface of approximately 500 objects each in two kindergartens in Taiwan were collected using the same number of the metallic probes. After being delivered to laboratory, the analytes on the probes were analyzed with thermal desorption-electrospray ionization/mass spectrometry (TD-ESI/MS). As sample pretreatment was unnecessary, the analysis of phthalates on a probe was completed within 30 s enabling high-throughput screening of a large number of objects. All procedure including sampling and TD-ESI/MS analysis together with report writing for a kindergarten was completed in one day. A reasonable relative standard deviation (<15.6%) was obtained from replicate analyses of phthalate standards. Single-point calibration was used to perform semi-quantitative analysis, and results were validated by liquid chromatography/mass spectrometry (LC/MS). It was found that 20-40% of the objects in two kindergartens contained greater than low-level (>2 ng) of phthalates and 40-60% of the objects in the kindergartens contained more than one kind of phthalate.