EPA332.0 /600/R-05/049饮用水中的高氯酸盐的测定离子色谱-电喷雾电离质谱法

标准资料 · 发表于 2017-8-19 15:53:01

This method describes the instrumentation and procedures necessary to identify and
quantify low levels of ClO4
- in drinking waters using IC-ESI/MS. Drinking water
samples are collected using a sterile filtration technique. A small volume of sample is
injected into an ion chromatograph. Using an anion exchange column, ClO4
- is
separated from constituent cations and anions in the sample using a potassium
hydroxide mobile phase. Due to the use of a non-volatile mobile phase, the eluate from
the column is passed through a conductivity suppressor to remove the potassium (K+)
ions of the mobile phase and to remove the analyte counter cations prior to the eluate
entering the mass spectrometer. An 18O-enriched 35Cl18O4
- internal standard (m/z 107) is
used for quantitation to improve accuracy and ruggedness of the method. Identification
is made by verifying the relative retention time of the two predominant ClO4
- ions with
respect to the internal standard. Qualitative confirmation of ClO4
- is made by
confirming that the m/z 99/101 area count ratio is within a specified range. If these
conditions are met, along with passing all other QC requirements defined in Section 9,
then the concentration obtained using the m/z 101 quantitation ion is reported.