Assessment of external calibration, internal standard calibration and quadruple isotope dilution strategies for the determination of acrylamide in wastewater samples after LC-MS/MS quantification

Abstract

Acrylamide is a possible neurotoxicant and carcinogen compound and its common usage in various industrial processes causes acrylamide contamination in environmental bodies. For this purpose, there is an increasing demand to develop an accurate and selective analytical method for the determination of acrylamide. In the scope of this study, external calibration (EC), internal standard calibration (ISC) and quadruple isotope dilution (ID4) strategies were compared to each other in terms of accuracy and precision. After the evaluation of these methods, liquid chromatography - quadruple isotope dilution - tandem mass spectrometry (LC-ID4-MS/MS) as a highly accurate and precise analytical approach was proposed to quantify acrylamide in wastewater samples. Several parameters for LC system such as sample injection volume, mobile phase type/composition and mobile phase flow rate were elaborately optimized to enhance peak shape and signal to noise ratio (S/N) belonging to the analyte. Under the optimum chromatographic and mass determination conditions, system analytical perfor-mance study was performed to determine dynamic range and limit of detection/quantitation (LOD and LOQ). LOD and LOQ values of the proposed LC-MS/MS method for the analyte were calculated as 1.18 and 3.93 mu g/kg; respectively. After the system analytical performance study, the spiking experiments in wastewater samples were carried out for the evaluation of accuracy and applicability of LC-MS/MS method. For wastewater samples, percent recovery results with their percent relative standard deviations (%RSD) obtained from EC, ISC and ID4 strategies were 115.8-177.8% (+/- 1.2-11.4%), 94.5-117.7% (0.3-4.7%) and 99.6-100.9% (0.4-1.7%); respec-tively. These results prove the superiority of ID4 strategy with regards to accuracy and precision of the results.