Identification And The Quantification Of The Human Pharmaceutical Residues In The East Lake In Wuhan China Using Liquid Chromatography And High Resolution Mass Spectrometry

Contaminants of emerging concern(CECs)are an unregulated suite of constituents frequently detected in environmental waters,which possess the potential to cause a host of reproductive and developmental problems in humans and wildlife.The “uncontrolled emerging contaminants” like pharmaceuticals enter our environment either,intact or transformation product after their intake.Residues of human drugs and their metabolites that are excreted by humans may flow into and through wastewater treatment plants.The aim of this study was to develop a method based on liquid chromatography high resolution mass spectrometry(LC-HRMS)for the identification and quantification of the human drugs and their metabolites and some other chemicals in East Lake.(1)Identification of human drugs was conducted using suspect screening approach.A self-data base about the m/z value of precursor ions,and fragment ions corresponding to about 250 pharmaceutical residues was created from the numerous studied literatures firstly.And Water samplers were than subjected to the SPE pretreatment and LCMS analysis.The SPE-LC-HRMS method was optimized like SPE operation conditions,liquid chromatography,and mass spectrometry parameters.The method applied was able to identify and confirm 28 human drugs and their metabolites in the East Lake in Wuhan china.Among the 28 human drugs,there are 5 antibiotics which are sulfamethoxazole,lincomycin,metronidazole,clindamycin,and trimethoprim.The most important finding were the metabolites of metamizole dipyrone namely,4 formylaminoantipyrine(4-FAA)and 4-acetylaminoantipyrine(4-AAA).These are also called xenobiotics.Irbesartan was also reported for the first time in the East Lake.It has not been previously reported in any lakes in China.These metabolites has not been reported anywhere before in the water medium of china.Metabolites of the pharmaceuticals have been the highlight of our developed method as not much focus has been given to these metabolites in the past and our method was able to identify these drug metabolites and most of which has not been reported before.(2)Quantification of the identified human drugs was performed via LC-HRMS using the same SPE and LC-HRMS parameters as that used in the identification process.The results of the quantification showed satisfactory results and complied with the acceptance defined criteria.The instrument limit of detection ranged from 0.01 μg/L to 2.5 μg/L.The Limit of detection was 0.01 μg/L for four compounds namely metformin,dextrorphan,Salbutamol,Valsartan,nicotine and cotinine.The limit of quantification ranged from 0.03 μg/L to 8.333 μg/L.The Method detection limit ranged from 0.025ng/L to 2.5 ng/L.The precision in terms of the repeatability and reproducibility were all satisfactory.Linearity was greater than 0.99.The recovery value ranged from 73%-120% and 70 % to 106% at two concentration level 12.5 ng/L and 25 ng/L using purified water and the East Lake water sample.The concentrations of the human pharmaceuticals and their metabolites determined were found to be ranged from 0.1 ng/L to 272.6 ng/L in East Lake,and the Tap water.The metabolite of the carbamazepine i.e.10-hydroxy carbamazepine showed the lowest concentration at the East Lake location I among all the locations of the East Lake analyzed and also as compared to the Tap water.The highest concentration was observed for caffeine 272.6 ng/L in the East lake location V.Gabapentin was missing in both the East Lake location II,III,V,VI,VII and VIII.The antibiotic lincomycin was not detected in the East lake location V.Sulfamethoxazole,4-FAA,dextrorphan and trans-3hy cotinine was absent in the tap water.These concentration values were lower and also comparable to the other concentrations of the other water medium and even Lakes performed in the other parts of the world.(3)Post-analysis was conducted for the identification of other chemicals in the water samples.Post-analysis means analyzing the old MS data obtained to suspect screening compounds that did not concerned before.Since the data is not discarded using this instrument and is available all the time,so retrospective studies were conducted to further investigate the presence of other contaminants in the East Lake with the main focus on the pesticides.In actual 12 pesticides were tentatively confirmed along with their main metabolites.Atrazine a persistent herbicide along with its four major degradation products hydroxyatrazine,desethyl atrazine,deisopropyl atrazine and didealkylatrazine were also detected and identified.Another important breakthrough was the detection of other chemical contaminants like DEET,triethyl phosphate,2 pipridinecarboxamide 1,3 dimethyl 3,4,6 tetrahydro Pyrimidinone and gamma undecalctone.Two isomeric cases were easily resolved using t-MS2 acquisition.Overall 44 contaminants were detected and identified which included 28 human pharmaceutical residues and their metabolites,12 pesticides and their metabolites and 4 other chemical contaminants.The method developed is robust and appropriate for the qualitation and the quantitation of the contaminants in the environment water at a low concentration.