Abstract |
A molecular spectral interference associated with a certain type of suspended particulate matter in natural waters is reported for the furnace atomic absorption determination of arsenic. In some water samples, arsenic concentrations were erroneously high by more than a factor of five above the actual concentration. Results of analyses were confirmed by an alternate analytical method. The degree of interference is a function of spectral bandpass and the concentration of hydrofluoric acid added to the sample. Use of 0.2-nm bandpass or 1% hydrofluoric acid markedly reduced the interference for the natural water samples investigated. |