Direct aqueous analysis of pesticides and PPCPs in drinking and bottled water at ppt levels

Using the SCIEX Triple Quad™ 7500 LC-MS/MS System − QTRAP^® Ready

Introduction

Drinking water analysis is subjected to extremely low and rigid prescribed consent values (PCV) for determinands. Water suppliers and utility companies need to ensure that the final water product they send out for bottling or into supply networks is safe and complies with state and country regulations. Water can be a challenging matrix, in particular if it is sourced from a river, lake or reservoir before entering the water treatment process. Laboratories which serve the water companies must have highly sensitive instrumentation to quantify beyond PCV limits with precision and confidence and be able to handle all the matrix challenges.

In this technical note brought to you by SCIEX, a series of experiments were conducted in collaboration with Vitens Water Company, to test several types of water samples spiked with a mixed standard of 431 determinands, including pesticides, pharmaceuticals, and personal care products (PPCPs). This work explores the sensitivity levels of the SCIEX Triple Quad 7500 LC-MS/MS System − QTRAP Ready, the reproducibility of the acquired data as well as the simplicity of data processing using SCIEX OS Software.

Figure 1. SCIEX 7500 System with an example of Chloramphenicol spiked in Fiji mineral water at 0.1 ng/L. This direct aqueous injection analysis removes the need for laborious sample preparation.

Methods

Sample preparation

Direct aqueous injection of spiked water samples — MilliQ water, tap water (SCIEX Concord Laboratory), Evian bottled water and Fiji bottled water. The samples were spiked with a custom mix standard provided by Vitens, Netherlands, containing 431 analytes, include 46 internal standards. A series of 12 standards were made in the respective matrices at sequential concentrations from 0.1 to 500 ng/L. A collection of unknown blank samples was also included in this study.

Due to the broad range of compounds analyzed in this study, polarity switching was used to maximize compound coverage. The speed of polarity switching ensured that very good peak sampling was obtained for all analytes, with sufficient data points across the LC peak (Figure 2).

Figure 2. All 431 compounds optimized for analysis with fast positive and negative switching. Extracted ion chromatograms (XIC) show the positive mode compounds (top) and the negative mode compounds (bottom).

Key features of the SCIEX 7500 System for drinking water analysis:

• Very high sensitivity demonstrated — Ready for sub part per trillion detection limits for analytes in drinking water
• Includes improvements in the generation of ions with the OptiFlow^® Pro Ion Source and the E Lens™ Technology and the capture of ions with the D Jet™ Ion Guide
• Simple sample preparation strategy of direct aqueous injection streamlines the water analysis workflow
• SCIEX OS Software is a single platform for data acquisition, data processing and streamlined results review
• QTRAP Ready system future proofs the lab with an easy upgrade path to obtain the qualitative functionality of the linear ion trap scan features

Conclusions

SCIEX Triple Quad 7500 LC-MS/MS System − QTRAP Ready has demonstrated its potential for low-level quantification (parts per trillion detection limits) across a relatively large suite of 431 determinands with robustness and scope for expansion.

For the full technical note which includes extra methods details, data and references, please visit: https://sciex.li/PPCP7500

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