顶空法测定海水中一氧化碳

Determination of Carbon Monoxide in Seawater by Headspace Analysis

建立了顶空分析法结合ta3000痕量气体分析仪测定海水中CO浓度的方法,对实验条件进行了选择,确定了环境温度、平衡时间和液气相比等最佳实验条件。结果表明,在20℃的环境温度下采用50mL玻璃注射器进行测定,液气相比为44∶6和平衡时间为5min能够较好地测定出海水中CO的浓度。在优化实验条件下,CO测定的线性范围为0～2.7×10-6(V/V),r=0.999,P<0.0001;相对标准偏差<4.4%;回收率为90.5%;检出限为0.02nmol/L。同时应用该方法测定了北黄海海水中的CO,测得CO的浓度是0.20～3.13nmol/L,表明该方法能够满足于海水中CO浓度的测定。

Oceanic carbon monoxide（ CO） has been of biogeochemical interest due to its significant role in global carbon cycle and the greenhouse effect. A headspace method coupled with ta3000 trace gas analyzer system for the determination of CO in seawater was developed. The effects of temperature,equilibrium time and water/gas volume ratio on the sensitivity of headspace analysis were studied in detail. The results showed that CO concentrations in seawater were measured successfully by the 50-mL glass-only syringes with a water/ gas volume ratio of 44∶6 and an equilibrium time of 5 min at 20 ℃ room temperature. Under the optimized conditions,the linear range of concentrations of CO was 0-2. 7 × 10-6,r = 0. 999,p 0. 0001. The relative standard deviation of the analysis method was 4. 4% ,with a detection limit of 0. 02 nmol/L. The average recovery of CO was 90. 5% . The concentrations of CO in surface waters of the North Yellow Sea were measured using this method and ranged from 0. 20 nmol/L to 3. 13 nmol/L,indicating that this method can be successfully applied to the detection of the in situ CO concentrations in seawater.