Determination of Phosphite, Phosphate, Glyphosate and Aminomethylphosphonic Acid by Two-Dimensional Ion Chromatography System Coupled with Capillary Ion Chromatography

Phosphite, phosphate, glyphosate and aminomethylphosphonic acid (AMPA) in natural water were determined by two-dimensional ion chromatography system coupled with capillary ion chromatography (2D-CIC). After filtrated by a 0.22-μm filter membrane, 25 μL of samples was injected into the first dimensional analytical column (AS11-HC) for preliminary separation. According to the different retention times in the first dimension, the target ions were divided into two groups (one group was phosphite and phosphate, another group was glyphosate and AMPA), then switched to the second dimensional capillary column (MAX-100) for further separation and detection. The effluent flow rates were 0.38 mL min −1 in the first dimension and 0.01 mL min −1 in the second dimension with KOH gradient elution, respectively. The carbonate removal devices were employed. The external standard method was used in all instances to quantitatively analyze. The results showed that the detection limits ( S/N = 3) were 0.18 nM for phosphite, 0.073 nM for phosphate, 0.15 nM for glyphosate and 2.6 nM for AMPA. The relative standard deviations (RSD, n = 6) of peak area ranged from 2.7% to 4.6%. The recoveries ranged from 80.1% to 118.4%. The results demonstrated that coupled capillary system could afford the simple detection of trace materials in natural water with complex matrix.