Fast and sensitive LC-MS detection of Bisphenol A and Butylhydroxyanisole in WWTP sewage sludge

In this study, a new LC-MS/MS method was developed and optimized in order to detect two omnipresent
additives, Bisphenol A (BPA) and Butylhydroxyanisole (BHA), in WWTP sewage sludge. Both analytes are
synthetic phenolic compounds known for their endocrine disruptive and toxic properties. BPA and BHA
were isolated from sludge samples using ultrasonic assisted liquid-solid extraction followed by silicagel
clean-up to remove interferences, and evaporation to dryness and extract re-dissolution with 1 mL methanol
prior to LC-MS analysis. All LC-MS parameters were optimized in order to obtain high sensitivity and selectivity. MS detector response was linear in the range 1 ÷ 200 μg/L with correlation coefficient R2 > 0.999 for both analytes. Intra-day and inter-day precision expressed as RSD values were 4.7% and 10.3% for BPA, whereas for BHA 7.8% and 13.8% RSD values were obtained. Recovery values after ultrasonic assisted extraction were 85.5% for BPA and 79.3% BHA with internal standard correction. Overall method LOQs were established at 1.97 ng/g (BPA) and 1.86 ng/g (BHA) on dry weight. Optimized chromatographic parameters allowed separation and detection of the two additives in less than 10 minutes. Both BPA and BHA were detected in all tested sludge samples with higher levels for BPA (34.6 - 132.6 ng/g), whereas BHA was found at lower levels in the range 3.16 - 5.64 ng/g.