Development of a method for the analysis of pregabal in wastewater using liquid chromatography-tandem mass

After taking illegal drugs into the body, like all other substances, the main compound and any metabolites are excreted through urine and feces, which are natural excretion routes, and mix with sewage, i.e. wastewater. Wastewater-based epidemiology (WBE) is a discipline based on the analysis of illegal substances, various drugs and chemicals taken from wastewater. As a result of the analysis, the concentration of the main substance or its metabolite, if any, is determined according to the desired substance, and thus the type and amount of illegal substance consumed in society can be determined. Analyzes made in wastewater are very important in order to monitor the use of illegal substances or pharmaceutical active substances such as Pregabalin, which are subject to control and have a risk of abuse due to their psychotropic effects. Thanks to wastewater studies, pregabalin use in a region can be monitored and studies on public health and awareness can be carried out. In this thesis study, it is aimed to develop a fast, practical, specific, low detection limit, high reproducibility and recovery method with the liquid chromatography - tandem mass spectrometry LC-MS/MS system for the analysis of pregabalin, whose abuse risk is increasing day by day, and to carry out validity studies. In order to validate the method, selectivity, limit of detection (LOD) and limit of quantification (LOQ), linearity, accuracy, precision and stability parameters were studied. In the study, the linear range of pregabalin was determined as 0.5-20ng/mL and the correlation coefficient in this range was found to be r2 = 0.9983. The LOD value was calculated as 0.05 ng/mL and the LOQ value was calculated as 0.1 ng/mL. %RSD values for the selected concentrations of 0.5, 1, 5 ng/mL were found to be 8.959, 5.732 and 13.663, respectively in the repeatability study for precision, 12.025, 4.625 and 10.724 in the inter-day repeatability study, and 8.834, 5.288 and 3.323 in the intermediate precision study. For the accuracy study, the recovery values of 0.5, 1, 5, ng/mL samples for tap water were found as 97.03%, 112.54% and 100.29%, respectively, from the solutions prepared by spiking pregabalin to tap water. The stability study was carried out by adding pregabalin to wastewater. In the stability study, the results of 0th hour fresh samples were compared with the samples kept at +4ºC for 48 hours, and the % degradation was calculated as 27.05%. With the validated method, composite samples (n=14) collected from 2 different wastewater treatment plants (WWTP) for 7 days were analyzed and pregabalin concentrations were found to be 1.519 ng/mL on average for WWTP 1 and 2.203 ng/mL on average for WWTP 2. The daily substance consumption calculation results were found to be an average of 535.231 mg/day/1000 people for WWTP 1 and 488.416 mg/day/1000 people for WWTP 2. It is thought that the method developed in this thesis study also contributes to the literature, forensic sciences and forensic toxicology laboratory. Although there have been previous studies on the analysis of legal and illegal drugs in wastewater in our country, since there is no study on the analysis of pregabalin in wastewater, an analytical method has been developed to detect pregabalin, which is increasingly abused, in wastewater. This study allowed the consumption amount of pregabalin to be monitored and made it possible to monitor periodic and regional differences and inform those responsible so that the necessary precautions could be taken.