ABSTRACT
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.