CN102980865A - Measurement method for seawater total nitrogen content - Google Patents

Measurement method for seawater total nitrogen content Download PDF

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Publication number
CN102980865A
CN102980865A CN2012104662346A CN201210466234A CN102980865A CN 102980865 A CN102980865 A CN 102980865A CN 2012104662346 A CN2012104662346 A CN 2012104662346A CN 201210466234 A CN201210466234 A CN 201210466234A CN 102980865 A CN102980865 A CN 102980865A
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Prior art keywords
seawater
total nitrogen
absorbance
measurement
nitrogen content
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CN2012104662346A
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Inventor
时旭
顾兆俊
刘兴国
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Fishery Machinery and Instrument Research Institute of CAFS
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Fishery Machinery and Instrument Research Institute of CAFS
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Priority to CN2012104662346A priority Critical patent/CN102980865A/en
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Abstract

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.

Description

A kind of assay method of seawater total nitrogen content
Technical field
The invention belongs to water quality standard test field, ocean, particularly the assay method of water body total nitrogen content in a kind of sea-farming.
Background technology
Sea-farming is to utilize shallow sea, beach, bay, enclose the mode of production that the marine products Economic animals and plants was raised and bred in the marine sites such as the pool, is one of human orientation important channel of utilizing living marine resources, Development of Marine aquatic products industry.In the sea-farming, the seawater total nitrogen is one of important indicator of reaction water quality, and total nitrogen refers to NH in the water body 4-N, NO 3-N, NO 2The general name of-N and organic nitrogen sum.
In the sea-farming, because a large amount of exogenous bait and excreta roll up N, P and organism in the water body, cause water quality deterioration, become one of principal element of restriction mariculture industry development.If in breeding process, can carry out Real-Time Monitoring to total nitrogen content in the water body, can in time obtain the relevant information of Water quality, thereby can take corresponding disposal route according to the variable quantity of total nitrogen in the water body.The assay method of seawater total nitrogen is GB GB/T12763.4-2007 at present, be specially: seawater sample is under alkalescence and 110 ℃~120 ℃ conditions, use potassium persulfate oxidation, organonitrogen compound is converted into nitrate nitrogen, simultaneously, the nitrous acid nitrogen in the water, ammonium nitrogen also are oxidized to nitrate nitrogen quantitatively.Nitrate nitrogen carries out diazo reaction with P-aminobenzene-sulfonamide after being reduced to nitrite, how reactant replaces the effect of ethylenediamine dihydrochloride with 1-again, generates the peony azo dyes, and the place carries out spectrophotometry in the 543nm wavelength.Because said method related to for two steps and transforms, not only step is complicated, length consuming time (common 6-8 consuming time hour), and produce the determination of total nitrogen content error because of Substance Transformation easily.And in the existing total nitrogen detection method, the use amount of sample use amount and reagent is also quite a lot of, has caused unnecessary waste.
Summary of the invention
The detection method that the purpose of this invention is to provide a kind of seawater total nitrogen content, the method just can obtain the content of total nitrogen by the content of the nitrate nitrogen in the direct test water body, and determination efficiency is high, the mensuration process is faster.
In order to realize above technique effect, the present invention realizes as follows:
A kind of detection method of seawater total nitrogen content, its step comprises:
(1) mensuration of titer absorbance: with the potassium nitrate titer with after the thinning agent dilution, add alkaline potassium persulfate solution oxidation, then cooling after the mixed liquor heating is obtained clearing up product, this clear up in the product add dissolve with hydrochloric acid solution after with the thinning agent dilution, utilize ultraviolet spectrophotometer to measure absorbance; According to absorbance correction value drawing standard curve.In the mixed liquor of potassium nitrate titer and thinning agent, the content of nitrogen is that 0-9 μ g/mL absorbance correction value is: measure absorbance A 220 and A275 with ultraviolet spectrophotometry respectively at wavelength 220 and 275nm place, and by formula 1., obtain the correction absorbance A:
A=A220-2A275。①
(2) mensuration of seawater sample absorbance: seawater sample is recorded absorbance according to the assay method of the absorbance in the step (1); According to the total nitrogen content in the typical curve calculation sample of drawing in the step (1).Namely the typical curve from step (1) is found corresponding nitrogen pool m, 2. calculates total nitrogen content with formula again.
Total nitrogen (mg/L)=m/v 2.
In the formula: the nitrogen content that m--checks in from typical curve (μ g)
V--institute water sampling volume (ml)
In the described step (1), the concentration of the nitrogen ion in the potassium nitrate titer is 9-10 μ g/mL.
In the described step (1), in the mixed liquor of potassium nitrate titer and thinning agent, the percent by volume 0-80% of potassium nitrate titer.
In the alkaline potassium persulfate solution of described step (1), solvent is without ammoniacal liquor, and potassium persulfate content is 35~45g/L; Sodium hydrate content is 12~16g/L.
Described ultraviolet spectrophotometer with without ammoniacal liquor as reference, the cuvette light path is 1cm, ultraviolet wavelength is that 220nm and 275nm place measure absorbance.
In the described step (1), thinning agent is sodium chloride solution, and the mass concentration of this sodium chloride solution is 32 ‰-37 ‰, and solvent is without ammoniacal liquor.
Described hydrochloric acid solution is that mass concentration is the hydrochloric acid of 30%-37% and is 1-2 without ammoniacal liquor according to volume ratio: 9 ratio is mixed.
The heating-up temperature of described mixed liquor is 120 ℃-124 ℃, and be 0.5-1 hour heat time heating time.
Described seawater is breeding seawater.
The invention has the beneficial effects as follows: the assay method of total nitrogen content in the marine culture water provided by the invention, lacked the nitrate nitrogen in the water body through being reduced to nitrite than the assay method of measuring seawater in the prior art, then carry out diazo reaction with P-aminobenzene-sulfonamide, how reactant replaces the effect of ethylenediamine dihydrochloride with 1-again, generate the process of peony azo dyes, but the content of directly testing the nitrate nitrogen in the water body just can obtain the content of total nitrogen, the mensuration process is easier, saves 2.5 hours than existing detection technique; Without the conversion of container, reduced experimental error in the described seawater determination of total nitrogen content method; The varieties of reagent that uses in the described seawater determination of total nitrogen content method is few, and consumption is few, has saved testing cost; Only relate to step conversion in the described seawater determination of total nitrogen content method, reduced material because of the error at measurment that multiple conversion produces, improved the detection accuracy.
Description of drawings
Fig. 1 is the typical curve that the present invention draws according to the absorbance correction value.
Embodiment
Below in conjunction with embodiment, the invention will be further described:
Test used equipment: ALP high-pressure sterilizing pot CL-32L, Merk Millipore water purification machine SheEA00003D, HACH ultraviolet spectrophotometer DR5000.
Test used reagent:
Sodium hydroxide solution: take by weighing 20gNaOH, be dissolved in without in the ammoniacal liquor, be diluted to 1000mL.
Alkalescence potassium persulfate solution: take by weighing 40g potassium persulfate (K 2S 2O 8), 15gNaOH is dissolved in without in the ammoniacal liquor, is diluted to 1000mL.
(1+9) hydrochloric acid: mass concentration is the hydrochloric acid of 30%-37% and is that 1: 9 ratio is mixed without ammoniacal liquor according to volume ratio.
Potassium nitrate stock solution: take by weighing 0.7218g through the pure KN O of top grade of 105 ℃~110 ℃ oven dry 4h 3Be dissolved in without in the ammoniacal liquor, move in the 1000mL volumetric flask, adding the 2mL methenyl choloride is protective agent, is settled to 1000ml without ammoniacal liquor.。
Potassium nitrate titer: the potassium nitrate stock solution used without 10 times of ammoniacal liquor dilutions get.
Sodium chloride solution: take by weighing 35gNaCl, be dissolved in without in the ammoniacal liquor, be diluted to 1000mL.
1, the drafting of typical curve
(1) draw respectively 0,0.50,1.00,2.00,3.00,5.00,7.00, the potassium nitrate standard solution of 8.00mL in the color comparison tube of 25mL, be diluted to the 10ml graticule with sodium chloride solution.
(2) add respectively 5ml alkalescence potassium persulfate solution in color comparison tube, the jam-pack grinding port plug is wrapped pipe close with gauze and bungee, in case advance to spill.
(3) color comparison tube is placed the steam boiler that disappears, heated 0.5 hour, venting makes the pressure pointer return zero.Then be warming up to 120 ℃~124 ℃, heated 0.5 hour.Mixed liquor is cooled to adds again (1+9) hydrochloric acid 1mL after the room temperature, be diluted to the 25mL graticule with sodium chloride solution.On ultraviolet spectrophotometer, with without ammoniacal liquor as reference, measure absorbance at 220nm and 275nm wavelength place respectively with the 10mm quartz colorimetric utensil.(4) with the absorbance of proofreading and correct as ordinate, in the solution nitrogen concentration as horizontal ordinate, the drawing standard curve.The specific standards curve is seen Fig. 1.
2, the mensuration of seawater sample
Get the 10mL seawater sample, press (2) to (4) operation of Specification Curve of Increasing step, then by proofreading and correct absorbance, find corresponding nitrogen pool at calibration curve, use formula: total nitrogen (mg/L)=m/v, calculating total nitrogen content is 64.19 μ g/mL again.
In the formula: the nitrogen content that m--checks in from typical curve (μ g)
V--institute water sampling volume (mL)
3, this detection method and now usefulness assay method precision comparison:
(1) with 3 seawater samples respectively with assay method of the present invention with now test with international method, concrete outcome is as shown in table 1:
Table 1
From the experimental result that obtains, the P value is 0.0752, greater than 0.05, can think that two method population variances equate, namely two methods are without significant difference, but existing less than normal with national standard method value, unsteady larger, and the detection numerical value that assay method of the present invention obtains is relatively stable.
(2) with 20 μ mol/L KNO 3As test sample, respectively with assay method of the present invention with now test with international method, and with SPSS software experimental result is carried out statistical study.Concrete outcome is shown in table 2a, table 2b:
Table 2a
Table 2b
By finding out that the p value is respectively 0.345 and 0.154 among table 2a and the table 2b, all greater than 0.05, so the measured value of two kinds of methods has all reflected actual value more accurately, but the standard deviation of the inventive method is less, and is more stable than international method.
(3) mensuration of concentration known potassium nitrate solution and the recovery
Standard sample KNO with this assay method mensuration 3Concentration is respectively 8 μ mol/L, 20.0 μ mol/L and 40.0 μ mol/L, and parallel 6 parts, and with SPSS software experimental result is carried out statistical study.
Table 3a the inventive method is known the mensuration of concentration potassium nitrate solution and the recovery to
The single sample t check of table 3b
3b can find out that the P value of three concentration is respectively 0.182,0.345,0.219 by table, all>0.05, shows that this method records the result and actual value there is no significant difference, illustrates that this method is feasible.
Can find out KNO from the measurement result of table 3a 3When concentration was 20 μ mol/L and 40 μ mol/L, the accuracy of the data obtained was in specialized range 5%, and the recovery also meets this value range of 90%-110%, and concentration is when being 8.0 μ mol/L, and accuracy is relatively poor.So the inventive method is not suitable for the very low seawater sample of nitrogen concentration, such as natural ocean water body.But for the water quality of seawater fishery cultivating, pollute more serious seawater the mensuration of total nitrogen more suitable.
4, adopt this assay method to the checking of glycocoll nitrogen oxygenation efficiency, recovery of standard addition and seawater sample recovery of standard addition:
(1) Glycine Oxidation rate
With glycocoll (C 2H 5NO 2) to become concentration be the organic nitrogen standard solution of 20.0 μ mol/L to solution preparation, parallel 3 parts, measures its NO 3-N content calculates organic nitrogen substance oxidation rate according to measured value and normal concentration, and concrete outcome is shown in Table 6.
Table 4
As shown in Table 4, organic nitrogen substance oxidation rate scope is 94.2671%-105.2407%, and average out to 99.144% meets the 94%-101% scope that GB is stipulated.
(2) glycocoll mark-on oxygenation efficiency
Be 20.0 μ mol/L KNO in concentration 3Add the organic nitrogen standard solution of 20.0 μ mol/L in the standard solution, parallel 3 parts, measure its NO 3-N content calculates mark-on organic nitrogen substance oxidation rate, and concrete test data is shown in Table 5.
Table 5
Data from table 5 as can be known, mark-on oxygenation efficiency scope is 97.925%-105.2407%, average out to 100.3636% meets the GB requirement substantially, shows that this assay method organic nitrogen substance oxidation rate and mark-on oxygenation efficiency meet total nitrogen analysis requirement.
(3) seawater sample recovery of standard addition
Get 6 parts in seawater sample, wherein add a certain amount of KNO in 3 parts 3Standard solution is measured respectively the NO3-N content before and after the mark-on, calculates thus the recovery of standard addition of seawater sample, and concrete data see Table 6.
Table 6
From the interpretation of table 6, seawater sample recovery of standard addition scope is 95.1043%-124.3671%, and average out to 107.2971% shows substantially to reach quantitative recovery.
In sum, the precision of improving one's methods, accuracy, the recovery and blank value satisfy the requirement of seawater determination of total nitrogen content, the organic nitrogen mark-on oxygenation efficiency of detection method of the present invention and the recovery of standard addition of seawater sample also meet the requirement of GB, this assay method detects data accurately, reliably, and easier than used determination of total nitrogen content method, saved the use amount that the work such as the immersion of middle step of converting and experimental ware and washing have reduced reagent.

Claims (9)

1. the detection method of a seawater total nitrogen content, its step comprises:
(1) mensuration of titer absorbance: with the potassium nitrate titer with after the thinning agent dilution, add alkaline potassium persulfate solution oxidation, then cooling after the mixed liquor heating is obtained clearing up product, this clear up in the product add dissolve with hydrochloric acid solution after with the thinning agent dilution, utilize ultraviolet spectrophotometer to measure absorbance; According to absorbance correction value drawing standard curve; In the mixed liquor of potassium nitrate titer and thinning agent, the content of nitrogen is 0-9 μ g/mL;
(2) mensuration of seawater sample absorbance: seawater sample is recorded absorbance according to the assay method of the absorbance in the step (1); According to the total nitrogen content in the typical curve calculation sample of drawing in the step (1).
2. the detection method of seawater total nitrogen content according to claim 1, it is characterized in that: in the described step (1), the concentration of the nitrogen ion in the potassium nitrate titer is 9-10 μ g/mL.
3. the detection method of seawater total nitrogen content according to claim 1 is characterized in that: in the described step (1), and in the mixed liquor of potassium nitrate titer and thinning agent, the percent by volume 0-80% of potassium nitrate titer.
4. the detection method of seawater total nitrogen content according to claim 1, it is characterized in that: in the alkaline potassium persulfate solution of described step (1), solvent is without ammoniacal liquor, and potassium persulfate content is 35~45g/L; Sodium hydrate content is 12~16g/L.
5. the detection method of seawater total nitrogen content according to claim 1 is characterized in that: described ultraviolet spectrophotometer with without ammoniacal liquor as reference, cuvette thickness is 1cm, ultraviolet wavelength is that the 220nm-275nm place measures absorbance.
6. the detection method of seawater total nitrogen content according to claim 1, it is characterized in that: in the described step (1), thinning agent is sodium chloride solution, and the mass concentration of this sodium chloride solution is 32 ‰-37 ‰, and solvent is without ammoniacal liquor.
7. the detection method of seawater total nitrogen content according to claim 1 is characterized in that: described hydrochloric acid solution is that mass concentration is the hydrochloric acid of 30%-37% and is 1-2 without ammoniacal liquor according to volume ratio: 9 ratio is mixed.
8. the detection method of seawater total nitrogen content according to claim 1, it is characterized in that: the heating-up temperature of described mixed liquor is 120 ℃-124 ℃, and be 0.5-1 hour heat time heating time.
9. the detection method of any seawater total nitrogen content in 7 according to claim 1, it is characterized in that: described seawater is breeding seawater.
CN2012104662346A 2012-11-17 2012-11-17 Measurement method for seawater total nitrogen content Pending CN102980865A (en)

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CN104596969A (en) * 2015-01-30 2015-05-06 四川清和科技有限公司 Rapid analysis method for total nitrogen in watershed
CN108490036A (en) * 2018-03-14 2018-09-04 上海外高桥造船有限公司 The assay method of salinity in a kind of water
CN108801955A (en) * 2018-07-04 2018-11-13 无锡天创伟业科技有限公司 A kind of resorcinol spectrophotometry for total nitrogen test
CN109297915A (en) * 2018-11-19 2019-02-01 江苏卓正环保科技有限公司 A kind of total nitrogen spectrophotometry based on new chemical formulation
CN110361348A (en) * 2019-08-22 2019-10-22 赵云红 A kind of total nitrogen detection system and its total nitrogen detection method for water quality detection
CN110927090A (en) * 2019-12-04 2020-03-27 龙佰四川钛业有限公司 Method for detecting nitro in denitration absorption liquid
CN110987918A (en) * 2019-12-23 2020-04-10 广东环凯微生物科技有限公司 Detection reagent and rapid detection method for total nitrogen in water

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Cited By (12)

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Publication number Priority date Publication date Assignee Title
CN104062247A (en) * 2014-06-16 2014-09-24 山东省科学院海洋仪器仪表研究所 Measurement device and measurement method for high-accuracy in-situ detection on pH of seawater
CN104062247B (en) * 2014-06-16 2016-09-21 山东省科学院海洋仪器仪表研究所 The measurement apparatus of a kind of high accuracy in-situ detection sea water pH and measuring method
CN104076007A (en) * 2014-07-10 2014-10-01 江苏省水产技术推广站 Method for measuring total content of nitrogen of fresh water quality
CN104155258A (en) * 2014-08-15 2014-11-19 广州衡创测试技术服务有限公司 Improved determination method for total nitrogen in water
CN104596969A (en) * 2015-01-30 2015-05-06 四川清和科技有限公司 Rapid analysis method for total nitrogen in watershed
CN104596969B (en) * 2015-01-30 2018-01-30 四川清和科技有限公司 Basin total nitrogen rapid analysis method
CN108490036A (en) * 2018-03-14 2018-09-04 上海外高桥造船有限公司 The assay method of salinity in a kind of water
CN108801955A (en) * 2018-07-04 2018-11-13 无锡天创伟业科技有限公司 A kind of resorcinol spectrophotometry for total nitrogen test
CN109297915A (en) * 2018-11-19 2019-02-01 江苏卓正环保科技有限公司 A kind of total nitrogen spectrophotometry based on new chemical formulation
CN110361348A (en) * 2019-08-22 2019-10-22 赵云红 A kind of total nitrogen detection system and its total nitrogen detection method for water quality detection
CN110927090A (en) * 2019-12-04 2020-03-27 龙佰四川钛业有限公司 Method for detecting nitro in denitration absorption liquid
CN110987918A (en) * 2019-12-23 2020-04-10 广东环凯微生物科技有限公司 Detection reagent and rapid detection method for total nitrogen in water

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Application publication date: 20130320