EPA Method 528 is a solid phase extraction (SPE)/gas chromatography/mass spectrometry screening method developed to measure 12 environmentally important phenols in drinking water and determine whether to regulate these contaminants in order to protect public health. Method 528 is an improvement over previous methods because MS affords positive identification of all 12 phenols without need for confirmation.*
Method 528 detection limits for phenols range from 0.02-0.58µg/L—concentrations below those needed for drinking water monitoring, based on current health effect information.
We developed a full set of standards for Method 528—calibration standard, internal standard, analyte fortification solution, surrogate standard, and GC/MS tune check solution. MS sensitivity to four of the phenols is significantly less than for the others, so we incorporate these at a higher concentration, 500µg/mL, in the fortification solution. Some of the substituted phenols exist as isomers that have similar mass spectra, but can be differentiated by retention time. The only coelutions are deuterated surrogates, which do not share common ions with the target analytes.
3-Nitro-
o-xylene (83-41-0), 1000 µg/mL
2,3,4,5-Tetrachlorophenol (4901-51-3), 2000 µg/mL
* Requirements for testing and analysis are outlined in Number 40 Code of Federal Regulations (CFR), Chapter 1, Part 141.40.
