Determination of 145 pharmaceuticals and personal care products in eleven categories in water by ultra-high performance liquid chromatography-triple quadrupole mass spectrometry

Abstract

Pharmaceuticals and personal care products (PPCPs) are emerging contaminants frequently detected in aquatic environments at trace levels. These chemicals have diverse structures and physicochemical properties and includes pharmaceuticals like antibiotics, antihypertensive drugs, antiviral drugs, and psychotropic drugs that are widely used in large quantities worldwide. Considering the large number of pharmaceuticals currently in usage, it is crucial to establish a priority list of PPCPs that should be monitored and/or treated first. An accurate understanding of the occurrence and levels of PPCPs in aquatic environments is essential for providing objective materials for monitoring these emerging contaminants. Therefore, accurate, efficient, sensitive, and high-throughput screening techniques need to be established for determining and quantifying PPCPs. This study developed a method for the determination of 145 PPCPs (grouped into eleven categories: antibiotics, antihypertensive drugs, antidiabetic drugs, antiviral drugs, β-receptor agonists, nitroimidazoles, H2 receptor antagonists, psychotropic drugs, hypolipidemic drugs, non-steroidal anti-inflammatory drugs, and others) in water. The method was based on large volume direct injection without sample enrichment and cleanup and used ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-MS/MS). Water samples were collected and filtered through a 0.22-μm regenerated cellulose (RC) filter membrane. Subsequently, Na2EDTA was added to the samples to adjust their pH to 6.0-8.0. Internal standards were mixed with the solutions, and because of the addition of Na2EDTA, the interference of metal ions could be eliminated in the determination of compounds, especially for tetracycline and quinolone antibiotics. Among the six filter membranes tested in this study (PES, PFTE-Q, PFTE, MCE, GHP, and RC), RC filter membranes were screened for water sample filtration. The UHPLC-MS/MS parameters were optimized by comparing the results of various mobile phases, as well as by establishing the best instrumental conditions. The 145 PPCPs were separated using an Phenomenex Kinetex C18 column (50 mm×3 mm, 2.6 μm) via gradient elution. The mobile phases were 0.1% (v/v) formic acid aqueous solution containing 5 mmol/L ammonium formate and acetonitrile for positive ion modes, 5 mmol/L aqueous solutions of ammonium formate and acetonitrile for negative ion modes. The samples were quantified using the scheduled multiple reaction monitoring (scheduled-MRM) mode with electrospray ionization in positive and negative ion modes. A standard internal calibration procedure was used to calculate contents of sample. The established method was systematically verified, and it demonstrated a good linear relationship. The average recoveries of the 145 PPCPs at the three spiked levels were in the range of 80.4%-128% with relative standard deviations (RSDs, n=6) of 0.6%-15.6%. The method detection limits (MDLs) ranged from 0.015 to 5.515 ng/L. Finally, the optimization method was applied to analyze the 145 PPCPs in 11 surface water samples and 6 drinking water samples. Overall, 93 (64%) out of the 145 analytes were detected. The total contents of the PPCPs in surface water samples ranged from 276.9 to 2705.7 ng/L. The detection frequencies of antidiabetic, antiviral, and psychotropic drugs were 100%. The total contents of the PPCPs in drinking water samples ranged from 140.5 to 211.5 ng/L, and antibiotics, antidiabetic drugs, and antiviral drugs comprised the largest proportion of analytes (by mass concentration) in drinking water samples. Our method exhibited high analytical speed and high sensitivity. It is thus suitable for the trace analysis and determination of the 145 PPCPs in environmental water and showed improved detection efficiency for PPCPs in water, indicating that it has a high potential for practical applications. This study can extend technical support for further pollution-level analysis of PPCPs in water and provide an objective basis for environmental management.