This application describes how to use automated online trace enrichment (SPE) cartridges and a rapid switching valve in a Rapid Resolution LC (RRLC) system for rapid analysis of chlorinated phenoxy acid herbicides. Using small 3.5- and 1.8-µm ZORBAX RRHT columns and an automated online SPE cartridge in place of the loading pump specified in the EPA method dramatically reduces the total analysis time and virtually eliminates the potential for sample cross-contamination.
This document details a method for the rapid analysis of chlorinated phenoxy acid herbicides in drinking water using EPA Method 555. It focuses on the use of small ZORBAX columns (3.5 and 1.8 µm) combined with an autoSPE (Solid Phase Extraction) cartridge and automated switching valve to reduce analysis time and eliminate sample cross-contamination.
The text provides experimental conditions for the Agilent 1200 Series Rapid Resolution LC system, including specific pumps, autosamplers, and detectors. It compares standard separation methods with trace enrichment procedures, demonstrating how scaling to smaller columns reduces solvent consumption and analysis time from 60 minutes to as low as 36 minutes.
| System | Agilent 1200 Series Rapid Resolution LC |
|---|---|
| Software | ChemStation 32-bit version B.02.01 |
| Organic Solvent | Acetonitrile |
| Detection | UV 230 nm |
| Sample Concentration | 100 pg/mL in methanol or 20 ng/L (20 ppb) in reagent water |
The method analyzes EPA 555 Group A chlorinated phenoxy acid herbicides, including picloram, chloramben, dicamba, bentazon, 2,4-D, dichlorprop, 2,4,5-TP, and acifluorfen.
The method uses small ZORBAX columns (3.5 and 1.8 µm) and online trace enrichment, reducing the total analysis time from 60 minutes to 36 minutes.
Online SPE assures 100% sample transfer to the analysis column and dramatically increases sensitivity by increasing the analyte mass delivered to the column.