Sensitive detection of benzophenone-type ultraviolet filters in plastic food packaging materials by sheathless capillary electrophoresis-electrospray ionization-tandem mass spectrometry.

While they are commonly used as ultraviolet (UV) filters in plastic food packaging materials, benzophenones (BPs) are reported as environmental endocrine disruptors, and some of them possess significant estrogenic activity. Therefore sensitive determination of the content of those UV filters in plastic polymers is of vital importance in safety assessment of food packaging materials. Here, the sheathless capillary electrophoresis-electrospray ionization-tandem mass spectrometry (CE-ESI-MS/MS) method is applied for the first time to sensitively detect BP-type UV filters in plastic food packaging materials. We investigate and optimize a variety of factors that may affect ESI-MS efficiency and CE separation. Sensitive detection of six BP-type UV filters is achieved using sheathless CE-ESI-MS/MS in conjunction with accelerated solvent extraction and solid phase extraction, with the limit-of-detection of 7 pg/mL-2.4 ng/mL. The method exhibits excellent inter/intra-day repeatability along with the advantages of efficient separation, rapid analysis, low sample consumption and high sensitivity. Six BP-type UV filters in eight different brands of plastic films obtained from supermarkets are successfully analyzed using the method. Good recoveries of 81.3-104.1% at three levels of spiked concentrations are achieved with low RSDs (n = 5) of 2.5-8.7%. Our study shows that the sheathless CE-ESI-MS/MS is a robust and reliable method for sensitive and rapid analysis of UV filters, which would be of potential application in safety assessment of plastic food packaging materials.