Properties and suitability of liquid electrode plasma optical emission spectrometry (LEP-OES) for the determination of potassium, lithium, iron, and zinc in aqueous sample solutions

The effects of different parameters and the nitric acid concentration on the sensitivity and repeatability of elemental analysis were characterized for liquid electrode plasma optical emission spectrometry (LEP-OES). In addition, internal standardization for LEP-OES was investigated. The developed LEP-OES method was used for the determination of lithium, potassium, iron, and zinc in aqueous solutions and in samples with high acid concentrations after microwave-assisted digestion. The results were compared with those obtained by inductively coupled plasma - optical emission spectrometry. The sensitivity was improved when the plasma parameters were optimized. In addition, some improvement in the accuracy and reproducibility of the results was achieved when internal standardization by gold was employed. However, due to the strong matrix effects, the calibration standards should be made as similar as possible to the sample matrix.

Automated summary

The LEP-OES method was developed for elemental analysis of lithium, potassium, iron, and zinc in aqueous solutions and samples with high acid concentrations. Optimizing plasma parameters improved sensitivity, and using gold as an internal standard led to improved accuracy and reproducibility of results. Calibration standards should be as similar as possible to the sample matrix due to strong matrix effects.