Combined investigating analysing method of sediment total nitrogen and phosphorus

Abstract

The invention discloses a method for determining total nitrogen and total phosphor in deposits and soil, firstly drying, crushing, screening and thoroughly mixing uniformly the fresh sample collected, and weighing a certain amount and placing in a digesting container and serving; adding digestant in the digesting container and mixing them uniformly; stopping closely with ground stopper, wrapping with gauze and placing in high pressure steam boiler and making high temperature digestion and cooling and taking out; absorbing digesting supernatant and scanning at 190nm-290nm wavelengths to determine the optimum absorption wavelength and background value; measuring light absorption value and obtaining total nitrogen; absorbing digesting supernatant, adding in color developing agent and developing color at constant volume, scanning at 650-750nm wavelengths, determining the optimum absorption wavelength, determining light absorption degree and obtaining total phosphor. And the method is especially applied to combined determination of total nitrogen and total phosphor of deposits and soils in rivers, lakes, reservoirs, seas, etc.

Description

1. Technical field [0001] The invention relates to a technical method for the determination of total nitrogen and total phosphorus in sediments and soils. Specifically, samples are combined and digested at one time, the best absorption peak is determined by wavelength scanning, and the background value is deducted to quickly and accurately measure total nitrogen and total Phosphorus method. 2. Background technology [0002] Many research data show that the content of total nitrogen and total phosphorus is positively correlated with the degree of eutrophication of lakes. Lake sediments are a collection of pollutants in the water environment, and most of the pollutants entering the lake water are deposited in the lake bottom mud. Therefore, lake sediments are archive records of watershed environmental changes and human impacts on the environment. Sediments reconstruct the lake's pollution history. At the same time, the nutrient salt in the sediment is also the internal load ...

AI Technical Summary

Problems solved by technology

Since the temperature, time, and reagents of the digestion have a great influence on the digestion, and the persulfate solution cannot be stored for a long time, a standard curve needs to be prepared at the same time for almost every measurement. Therefore, the separate determination of total nitrogen and total phosphorus is time-consuming, labor-intensive and expensive It is cumbersome, for example, it is very difficult for one person to undertake the determination of these two items at the same time and a large number of samples

The persulfate oxidation method has been widely used in the determination of total nitrogen and total phosphorus in water, but this method has also been reported abroad in recent years for the determination of total nitrogen and total phosphorus in sediments. Due to the complexity of sediment components, the absorption of light by digestive juice The background is different from water samples. If you still choose to measure at two wavelengths of 220nm and 275nm, the results are often very unsatisfactory. It is necessary to scan the wavelength of its digestion solution to avoid the sensitive absorption area of ​​the digestion solution itself to determine the best Absorb the wavelength and subtract the background value to get accurate measurement results

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