Background:
The combination of cloud point extraction (CPE) with inductively coupled plasma-optical emission spectrometry (ICP OES) is limited due to the effect of organic diluent and surfactant on the signal.
Method:
dual-CPE process (d-CPE) was presented for the enrichment of aluminum (Al3+), before determination by ICP OES, to exclude the effect of surfactant and organic solvent on the ICP OES signal. The analyte was firstly extracted into Triton X-114 rich phase as a gallic acid complex. In the second step, Al3+ was back extracted into an aqueous phase of HNO3 that was introduced into ICP OES. The effects of pH, concentrations of gallic acid and Triton X-114, incubation temperature and time, centrifugation conditions and the concomitant ions were evaluated.
Results:
The method displayed good analytical characteristics at the optimum conditions. An enrichment factor of 49.5 was achieved. The linear calibration graph was obtained from 1.0 to 1000 µg L-1 and the detection limit was 0.31 µg L-1 . The relative standard deviation was 2.3% (50 µg L-1 Al3+, n = 10). Quantitative recoveries ranging from 96.0 to 100% were obtained for spiked water and geological samples. This procedure was used efficiently for preconcentration and quantification of Al3+ in various samples by ICP OES.
Conclusion:
The presented procedure is simple, rapid, accurate, and safe. It can be used for the determination of Al3+ by ICP OES in samples with complicated matrices.
Preconcentration and determination of As, Cd, Pb and Bi using different sample introduction systems, cloud point extraction and inductively coupled plasma optical emission spectrometry