Mixed Matrix Membrane Tip Extraction Coupled with UPLC–MS/MS for the Monitoring of Nonsteroidal Anti-Inflammatory Drugs in Water Samples

Thipashini Ganesan,Hong Ngee Lim,Nurul Hazirah Mukhtar,Hong Heng See

doi:10.3390/separations7010019

Thipashini Ganesan, Hong Ngee Lim + Show 2 more

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https://doi.org/10.3390/separations7010019

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Abstract

An ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method, in combination with a mixed matrix membrane microextraction method for the quantification of nonsteroidal anti-inflammatory drugs (NSAIDs) in environmental water samples, is reported. The extraction device was prepared by casting well-dispersed polymeric bonded octadecyl (C18) particles in a cellulose triacetate matrix solution onto commercially available 200 μL micropipette tips. The membrane formed contains 25% of the adsorbent loading amount and was firmly attached to the inner wall of the membrane tip. The dynamic extraction was performed by withdrawing and dispensing the sample solution through the tip device for effective analyte adsorption, followed by the analyte desorption process into 40 μL of methanol and acetonitrile (1:1) prior to UPLC–MS/MS analysis. NSAIDs—namely diclofenac, ibuprofen, indoprofen, naproxen and sulindac—were chosen as targeted analytes. Several extraction parameters were comprehensively optimized, including sample pH value, ionic strength, dynamic extraction cycle, desorption solvent and desorption time. The optimized conditions demonstrated a linear range from 0.25 to 500 ng L−1, with correlation coefficients (r2) from 0.9988 to 0.9992 and detection limits ranging from 0.08 to 0.40 ng L−1. The recoveries of the spiked water samples were between 92% and 99% and exhibited excellent precision relative to standard deviations (RSDs ≤ 4.9%), and enrichment factors (EFs) were at 201–249 for the developed approach.

Highlights

The sample preparation method is commonly employed for the isolation of potential interference in the sample and, at the same time, enriches the targeted analyte at the ultra-trace level to achieve the detection limits
The membrane showed a high affinity for nonsteroidal anti-inflammatory drugs (NSAIDs) in different spiked water samples, with enrichment factors (EFs) from 79 to 82, relative recoveries ranging from 84% to 104%, and RSDs between 0.2% and 8.6% (n = 9)
A blank analysis of wastewater performed by conventional solid phase extraction (SPE) polymeric bonded octadecyl (C18 ) cartridges [12] using UPLC–MS/MS showed that the NSAIDs were free of contamination

Summary

Introduction

The sample preparation method is commonly employed for the isolation of potential interference in the sample and, at the same time, enriches the targeted analyte at the ultra-trace level to achieve the detection limits. Single-layer graphene (SLG), multiwall carbon nanotubes (MWCNTs) and polymeric bonded octadecyl (C18 ) particles are examples of adsorbents that have successfully immobilized within the extraction membrane device to monitor the ultra-trace level of priority organic pollutants and pharmaceuticals in environmental waters [12,13]. This approach was proven to be a simplified experimental setup with low costs. Other variations of extraction based on a mixed matrix membrane were reported with satisfactory practicability [15,16,17]

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