采用一维分析系统串联二维毛细管离子色谱法测定天然水体中痕量亚磷酸根(HPO2-3)、磷酸根(H2PO-4)、草甘膦(Glyphosate)和氨甲基膦酸(AMPA)。样品经过0.22μm滤膜过滤后,进样25μL,先经过一维AS11-HC离子色谱柱进行初步分离,根据目标离子在一维系统中的出峰时间,将其切换至二维MAX-100毛细管色谱柱分离,KOH梯度淋洗,一维流速0.38mL/min,二维流速0.01mL/min,抑制电导检测。以信噪比S/N=3计算检出限,4种目标物的检出限分别为0.18nmol/L(HPO2-3),0.073nmol/L(H2PO-4),0.15nmol/L(Glyphosate)和2.6nmol/L(AMPA),峰面积的相对标准偏差(RSD,n=6)为2.7%~4.6%。4种物质在太湖水样中的加标回收率为80.1%~118.4%。
A method was developed for the determination of phosphite, phosphate, aminomethylphosphonic acid (AMPA) in natural water by two-dimensional ion chromatography with capillary ion chromatography (2D-CIC). After filtrated by 0.22 ixm filter membrane, 25 glyphosate and system coupled μL of samples was injected into the first dimension, where an AS11- HC analytical column was used, for preliminary separation. According to the retention time in the first dimension, the target ions were switched to MAX-100 capillary column of the second dimension for further separation. The flow rates were 0.38 mL/min in the first dimension and 0.01 mL/min in the second with KOH gradient elution, respectively. Suppressed conductivity detectors were employed for detection. The external standard calibration curve was used for the quantitative analysis. The results showed that the detection limits (S/N = 3 ) were 0. 18 nmol/L for phosphite, 0. 073 nmol/L for phosphate, 0.15 nmol/L for glyphosate and 2.6 nmol/L for AMPA. The relative standard deviation (RSD, n = 6) of peak area ranged from 2.7% to 4.6%. The recoveries ranged from 80.1% to 118.4% .