Application Note: Trace Analysis Of Chlorinated Herbicides In Water With Online Enrichment

By Srividya Kailasam Agilent Technologies, Bangalore, India

Herbicide contamination in water bodies is monitored to mitigate adverse health impacts. Sensitive methods for detecting and quantifying trace levels of these chemicals are necessary to meet regulatory requirements. Although offline SPE can help enrich target analytes from complex matrices, the methods use expensive cartridges and lengthy protocols making them less suitable for routine use.

This Application Note describes a simple, sensitive, and rugged LC method for the routine analysis of water for quantifying eight chlorinated herbicides. The analytes are initially trapped on an enrichment column fitted on a six port/two-position switching valve. Subsequently, they are eluted from this column and transferred to the analytical column for separation followed by UV detection with the sensitive diode array detector (DAD) of the Agilent 1260 Infinity LC system.

The US EPA Method 5551 describes the use of online sample enrichment for the analysis of chlorinated herbicides in 20 mL of water. An earlier Application Note2 describes in detail the advantages of using sub-2-µm columns for rapid and sensitive analysis of smaller sample volumes. This Application Note describes a method with automated sample cleanup for the assay of eight chlorinated herbicides using less than 2 mL of water.