Unusually high levels of bisphenol A (BPA) in thermal paper cash register receipts (CRs): development and application of a robust LC-UV method to quantify BPA in CRs

Abstract

We have developed a simple, reversed-phase high-performance liquid chromatography (RP-HPLC) method for the determination of bisphenol A (BPA) in thermal paper cash register receipts (CRs). The method is suitable for analysis of other types of bisphenols and it involves an overnight extraction of CRs with acetonitrile (AN) at 50 °C followed by the HPLC analysis on a Supelcosil LC18 column (150 × 4.6 mm, particle size: 5 μ) using 50% AN in water as the mobile phase (5 min, isocratic). The composition of AN in the mobile phase changed to 100% over a 10 min period (linear gradient) and then held at 100% AN for 10 min (isocratic). The flow rate was set at 1 mL/min (injection volume: 20 μL) and the eluent was monitored at 234 nm. The authentic BPA eluted with a retention time of 5.9 min and gave a linear detector response in the concentration range of 0.23–50 mg/L. BPA in the CR extracts also eluted with the same retention and had identical absorbance properties as the standard. When CR extracts were co-injected with authentic BPA, they were resolved as a single peak. Further, GC/MS/EI analysis of authentic BPA and the HPLC-purified CR extracts have identical ion chromatograms and fragmentation of the molecular ion (m/z = 228). We have analyzed 170 CRs collected from 62 different vendors including supermarkets, fast food restaurants, gas stations and banking outlets. Almost all cash receipts (n = 168) showed the presence of BPA in the concentration range of 0.45–4.26% (M ± SD, 1.54 ± 0.73%).

• Method development for BPA
• MS–EI detection
• RP-HPLC
• thermal paper cash receipts

Acknowledgements

The authors acknowledge Wesley Grey and Kinesha Harris for their help with HPLC instrumentation, and Amy Hernandz for help with GC experiments.

Declaration of interest

The authors report no conflicts of interest. The authors are responsible for the content and writing of the article.

This publication was made possible by grants from National Institutes of Health (P20RR16456), National Science Foundation (HRD1043316), and the US Department of Education (PO31B040030).