两种不同消解方法测定近海沉积物氮磷含量的比较

采用两种不同的消解方法—微波消解法和高压消解法,对近海沉积物中的总氮、总磷进行同时消解,并比较了测定结果.结果表明:高压消解条件下测定样品1和样品2总氮的相对标准偏差分别为7.7%和7.4%,总磷的标准偏差分别为3.9%和7.8%;微波消解条件下测定样品1和样品2总氮的相对标准偏差分别为9.4%和10.1%,总磷的相对标准偏差分别为6.9%和8.1%;两种消解条件下的总磷含量相差不大(样品1分别为0.460 mg/kg和0.454 mg/kg,样品2分别为0.449 mg/kg和0.439 mg/kg),但高压消解条件下的总氮含量(样品1为0.114 mg/kg,样品2为0.122 mg/kg)明显高于微波消解(样品1为0.088 mg/kg,样品2为0.092 mg/kg),且相对标准偏差较小.因此可以认为高压消解方法的精密度高于微波消解方法.

Comparison Study of Two Different Digestion Methods in Determination of Nitrogen and Phosphorus Content in Off-Shore Sediments

At the same time, the total nitrogen and total phosphorus in the off-shore sediments were simultaneously eliminated by two different methods of digestion, microwave digestion and high pressure digestion, and the results were compared. The results show that the relative standard deviations of total nitrogen in sample 1 and sample 2 were 7.7% and 7.4% respectively, and those of total phosphorus were 3.9% and 7.8% under high pressure digestion; meanwhile the relative standard deviations of total nitrogen in sample 1 and sample 2 were respectively 9.4% and 10.1%, and the standard deviations of total phosphorus were 6.9% and 8.1% under microwave digestion; the content of total phosphorus under the condition of two kinds of dispelling were similar (sample 1 total phosphorus content were 0.460 mg/kg and 0.454 mg/kg, sample 2 total phosphorus content were 0.449 mg/kg and 0.439 mg/kg), but total nitrogen content under the condition of high pressure digestion (sample 1 to 0.114 mg/kg, sample 2 was 0.122 mg/kg) were significantly higher than those of microwave digestion (sample 1 to 0.088 mg/kg, sample 2 was 0.0.092 mg/kg), and the relative standard deviation was less than that. Therefore, the high pressure digestion method is more precise than microwave digestion.