Determination of Caffeine and Its Metabolites in Wastewater Treatment Plants Using Solid-Phase Extraction and Liquid Chromatography–Tandem Mass Spectrometry

Abstract

For caffeine and its seven major metabolites (i.e., theobromine, theophylline, paraxanthine, 1-methylxanthine, 3-methylxanthine, 7-methylxanthine, and xanthine), an optimized analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for their detection in wastewater samples was developed in this study. Extraction of these compounds (recoveries ranged from 60.3 to 83.2%) was made possible by combining universal polymeric reversedphase cartridge and polymeric strong cation exchange cartridge. This method was applied to the determination of caffeine and its metabolites in the influent and effluent of an anaerobic-anoxic-oxic (A2O) process. In the A2O influent, caffeine and its metabolites (except xanthine) ranged from 1.39 to 5.45 μg/L, and their concentrations in the A2O effluent ranged from 10.2 to 171.3 ng/L. The mass load of caffeine was 14.9 g/day/1000 inhabitants, considering the population served by the target wastewater treatment plant (WWTP). The concentration of caffeine derivatives in wastewater influent is a tool for estimating the population size in the area served by WWTPs.

Recognition and Prioritization of Chemical Mixtures and Transformation Products in Chinese Estuarine Waters by Suspect Screening Analysis

“…As shown in Table S5–S6, 28 TPs of 8 parent compounds were found. The 8 TPs at CL = 2a could be easily recognized as products of 4-nitrophenol, atrazine, caffeine, and prometryn, and the presence in the environment has been further confirmed through literature retrieval. − Close similarity of the molecular structures between the parent compounds and TPs were found, and preservation of the main ionizable groups (i.e., phenolic hydroxyl and heterocycle ring) allows for SQ analysis using the calibration curves of the parent compounds. Meanwhile, the other 20 TPs were tentatively classified as CL = 3.…”

Polar licit and illicit ingredients in dietary supplements: chemometric optimization of extraction and HILIC-MS/MS analysis

“…It must be noted that only two responses were particularly important but in contrast: RT SLBT and R TFL-PRX , which presented different behaviors with respect to the investigated variables. The first is crucial because it represented the time of the analysis, being SLBT the last compound eluted in each tested condition; while R TFL-PRX (whose coefficients plot of its model is reported in Figure S.3 ) was critical due to the impossibility of distinguishing PRX from TFL with the employed MS/MS detection [ 59 ], thus making necessary to separate them chromatographically. The factors temperature and flow presented divergent effects on these two responses: Fig.…”

Application of D-Limonene as a Bio-based Solvent in Low DensityDispersive Liquid?Liquid Microextraction of Acidic Drugs from Aqueous Samples

“…Upon considering the impact of analytical procedures to the environment, sample preparation was found to be the most challenging step regarding the green parameters of a method. Solid-phase extraction was commonly used in the extraction of organic [2][3][4][5][6] and inorganic [7][8][9] contaminants from aqueous samples. It is also considered to be the main source of laboratory chemical waste.…”