Quantitative analysis of Phthalate Esters by in-situ thermal desorption atmospheric pressure photoionization mass spectrometry using a dopant as the internal standard.

Phthalate Esters (PAEs) are a group of chemicals widely used in plastic products, and they are also known as endocrine disruptors that can adversely affect the hormonal balance in humans. Since many food-contacting items, such as lunch boxes, fresh keeping film, disposable cups, are made of plastic, the PAEs can easily enter the human body through the polluted foods or drinks. Traditional analytical techniques involve laborious sample pretreatment and low-throughput analysis, so it is necessary to develop techniques that can rapidly and quantitatively detect these compounds. In this article, a miniaturized ion trap mass spectrometer (ITMS) was established firstly, then, an in-situ thermal desorption atmospheric pressure photoionization (in-situ TD-APPI) was designed, and the dopant was explored using for improving the sensitivity and as internal standard (IS) simultaneously in the analytical process. The in-situ TD-APPI presents good performance: (1) More than 20 times improvement in sensitivity compared with Nano-ESI for PAEs; (2) 12 kinds of phthalates were quantified with using acetone as the IS, and the LODs and LOQs ranges were found to be 0.02–1 μg/mL and 0.02–100 μg/mL, respectively. The technique was also applied to the quantification of mixed solutions, and the results were validated by LC/MS. Finally, six categories of food-contacting items containing PAEs were analyzed with superficial content (ng/cm2) ranging from 0 to 6.20 ng/cm2. These results demonstrate the potential of rapid quantification of analysis of PAEs in practical plastic food-contacting items by in-situ TD-APPI. • More than 20 times improvement in sensitivity was achieved compared with Nano-ESI for PAEs. • 12 kinds of phthalates were quantified, and the LODs and LOQs ranges were found to be 0.02–1 μg/mL and 0.02–100 μg/mL, respectively. • Within 3 s, this technique was applied to quantitatively analyze a mixed solution, and the results were validated by LC/MS. • Six categories of food-contacting items including tinfoil, lunch box, fresh keeping film, disposable cups, dinner plate and plastic spoon were analyzed. [ABSTRACT FROM AUTHOR]