Study on preservation method of nitrogen and phosphorous in high salinity seawater

In this paper, 12 different preservation methods were used to save 4 kinds of nitrogen and phosphorus nutrients (NH3-N, NO2-N, NO3-N, PO4-P) in high salinity sea water of salinity 32. We studied the parameter values' stability of 4 kinds of nutrients in 9 days storage using FIAstar5000 nutrient flow injection analyzer. The results showed that there were obvious differences among different preservation methods, the best preservation conditions of each nutrient was different. In 9 days experimental period, NH3-N in water samples had a large change tend, the NH4-N and PO4-P content presented a trend of decrease, while NO2-N and NO3-N content slightly rose. When chloroform was added into water samples, it was very good for the preservation of nitrogen nutrient (NH3-N, NO2-N and NO3-N); when formaldehyde was added, it was good for the preservation of phosphorus nutrient (PO4-P). Considered the effectiveness and operability of the experiment results, we obtained the optimal preservation condition of the 4 kinds of nutrient in 9 days. When 5译 chloroform was added into water samples, the stability of NH3-N could be controlled more than 80%; when 1 chloroform was added into water samples and the water samples were stored at -20, the stability of NO3-N could be over 95%; when 5译chloroform was added at -20 or 1译chloroform was added at 4益into water samples, the NO2-N could be more than 95%; when 5译formaldehyde was added at 4, it was the best method to save PO4-P.