Determination of Haloacetic Acids in Water by LC/MS
Introduction
Haloacetic acids (HAAs) are disinfection byproducts (DBPs) of the chlorination of drinking water. Dichloroacetic acid and trichloroacetic acid are animal carcinogens. We present an ion-pair HPLC and negative electrospray ionization mass spectrometry (ESI-MS) method with a “function-switching” feature for analysis of all 9 haloacetic acids, monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), monobromoacetic acid (MBAA), bromochloroacetic acid (BCAA), dibromoacetic acid (DBAA), bromodichloroacetic acid (BDCAA), trichloroacetic acid (TCAA), chlorodibromoacetic acid (CDBAA), and tribromoacetic acid (TBAA). JEOL MassCenter™ software can switch different MS settings by the time course. This “function-switching” feature enables each HAA to be analyzed under its optimized MS conditions so that the highest sensitivity can be achieved. Using triethylamine (TEA) as an ion-pairing reagent, a good HPLC separation of all 9 HAAs has been achieved. The optimized MS conditions for each HAA were evaluated.
Experimental
The system included a JEOL AccuTOF™ time-of-flight mass spectrometry system and an Agilent 1100 HPLC. Complete system control and data evaluation were carried out using a JEOL MassCenter™ workstation.
All solvents used were of HPLC grade. The standard solutions were prepared by mixing 9 HAAs in water with the concentration ranging from 0.1 μg/mL to 100 μg/mL.