Sequential determination of multi-nutrient elements in natural water samples with a reverse flow injection system

Publication date: 15 May 2017
Source:Talanta, Volume 167
Author(s): Kunning Lin, Jian Ma, Dongxing Yuan, Sichao Feng, Haitao Su, Yongming Huang, Qipei Shangguan
An integrated system was developed for automatic and sequential determination of NO2⁻, NO3⁻, PO4³⁻, Fe²⁺, Fe³⁺ and Mn²⁺ in natural waters based on reverse flow injection analysis combined with spectrophotometric detection. The system operation was controlled by a single chip microcomputer and laboratory-programmed software written in LabVIEW. The experimental parameters for each nutrient element analysis were optimized based on a univariate experimental design, and interferences from common ions were evaluated. The upper limits of the linear range (along with detection limit, µmolL⁻¹) of the proposed method was 20 (0.03), 200 (0.7), 12 (0.3), 5 (0.03), 5 (0.03), 9 (0.2) µmolL⁻¹, for NO2⁻, NO3⁻, PO4³⁻, Fe²⁺, Fe³⁺ and Mn²⁺, respectively. The relative standard deviations were below 5% (n=9–13) and the recoveries varied from 88.0±1.0% to 104.5±1.0% for spiked water samples. The sample throughput was about 20h⁻¹. This system has been successfully applied for the determination of multi-nutrient elements in different kinds of water samples and showed good agreement with reference methods (slope 1.0260±0.0043, R²=0.9991, n=50).

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