The invention belongs to the field of sea
water quality standard measurement, and particularly relates to a measurement method for water
total nitrogen content in
seawater culture. Firstly,
absorbance of standard liquid is measured, and the steps of measurement include that after the
potassium nitrate standard liquid is diluted by means of diluents, alkaline
potassium persulfate solutes are added for oxidation, the mixing liquid is heated and then cooled,
digestion products are obtained,
hydrochloric acid solutes are added into the
digestion products, the
digestion products are diluted by diluents after being dissolved, the
absorbance is measured by means of an
ultraviolet spectrophotometer, and a
standard curve is drawn according to an adjusted value of the
absorbance. Then a
seawater sample is measured according to measurement steps of the absorbance of the standard liquid, the value of the absorbance is obtained, and eventually the
total nitrogen content in the sample is calculated according to the
standard curve. Compared with a measurement method for
seawater in the prior art, the measurement method omits a middle conversion process, measurement steps are simple, convenient, quick and precise, and measurement time is 2.5 hours shorter than that of an existing measurement method. According to the measurement method,
reagent variety is few, used amount of reagents is little, and
measurement cost is saved.