固相萃取-离子色谱法测定土壤中亚硝酸盐和硝酸盐
IC Determination of Nitrite and Nitrate in Soil with Solid Phase Extraction
-
摘要: 提出了离子色谱法测定土壤中亚硝酸盐和硝酸盐的方法。土壤试样经水超声浸取,采用OnGuardⅡP和OnGuardⅡRP固相萃取柱净化,以AS11-HC为分析柱、AG11-HC为保护柱,萃取液中的NO2-和NO3-用15 mmol·L-1氢氧化钾溶液洗脱分离,并用抑制电导检测器同时测定其含量。亚硝酸盐和硝酸盐质量浓度分别在0.01~1.00 mg·L-1和0.10~10.0 mg·L-1范围内与对应的峰面积呈线性关系,方法的检出限(3s/k)分别为0.16,0.24 μg·g-1。方法的加标回收率分别在85.0%~100%和93.5%~106%之间,相对标准偏差(n=7)分别在2.9%~4.1%和2.2%~3.4%之间。Abstract: Contents of NO2- and NO3- in soil were determined by ion chromatography (IC). The sample was extracted ultrasonically with water and purified by passing through OnGuardⅡP and OnGuardⅡRP solid phase extraction columns. The 2 anions in the extract were separated on AS11-HC column with AG11 as guard column, by elution with 15 mmol·L-1 KOH solution as mobile phase and detected by inhibitory conductivity detection. Linear relationships between values of peak area and mass concentration of NO2- and NO3- were kept in ranges of 0.01-1.00 mg·L-1and 0.10-10.0 mg·L-1 respectively. Values of detection limit (3s/k) found were 0.16 μg·g-1(for NO2-) and 0.24 μg·g-1 (for NO3-). Tests for recovery and precision were made, giving values of recovery and RSD′s (n=7) in the ranges of 85.0%-100% and 2.9%-4.1% for NO2-, 93.5%-106% and 2.2%-3.4% for NO3- respectively.