Sustainable pretreatment of blood samples using hydrophobic eutectic solvents to improve the detection of bisphenol A†

Bisphenols, and mostly bisphenol A (BPA), are widely used in many consumer products. Due to its toxicity, BPA presents a noteworthy risk to the environment and human health. Despite these concerns, monitoring BPA proves challenging, particularly in highly complex matrices such as blood, because extraction and clean-up require multiple steps, the use of volatile organic solvents, and associated high costs. To overcome these limitations, this work discloses a novel, one-step and sustainable pretreatment technique of blood samples using hydrophobic eutectic solvents (HES). Systems composed of different HES, including thymol : menthol, benzyl alcohol : cyclohexanol, and decanoic acid : trioctylphosphine oxide at various mole ratios, combined with potassium citrate buffer aqueous solutions at different volume ratios, were carefully evaluated as three-phase partitioning (TPP) systems. The high performance of the HES-based systems for the pretreatment of blood samples was confirmed with liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis, with a BPA recovery of (98 ± 3)% in the HES-rich phase, and with the interfering biological material precipitating at the liquid–liquid interphase. The green nature of the developed method was assessed using the Analytical GREENess Metric (AGREE) and the AGREE metrics of environmental impact of sample preparation (AGREEprep), scoring 0.59 and 0.63, respectively. The high pretreatment performance offered by HES-based TPP systems with respect to blood samples, combined with their greener credentials, paves the way for their application in a variety of biomonitoring studies.