GB 17378.4-2007The specification for marine monitoring - Part 4: Seawater analysis (English PDF)

4.1 Reagents, solvents, membrane purification and treatment

4.1.1 ammonia isothermal diffusion method Purification. each containing ammonia and high water on the glass container division dryer separator or lower deck, Closed place. Diffusion time depends on temperature may be about 1 week to 2 weeks.

4.1.2 chloroform, carbon tetrachloride purification. the opening of the new solvent can be a simple process that added 200mL of hydrochloric acid per liter of solvent Hydroxylamine solution (0.5% volume fraction), shaking in a separatory funnel and washed aqueous phase was discarded, and washed with water once, dried over filter paper Filter can be. If the recovery of waste as a solvent or after the above-described method of treatment is still not eligible, instead dismount treatment. Pour the solvent into the distillation flask to half Full, plus the amount of sodium sulfite solution (10% volume fraction) overlying the upper right amount, for the first time distillation, then transferred to another clean retort Added solid calcium oxide second distillation, the distillate was discarded early a little, then take distillate, stored in a brown bottle. If the solvent is chloroform, can be added 1% by volume of ethanol, to increase its stability. 4.1.3 0.45µm fiber membrane treatment. polyethylene film coated with stainless steel tweezers pinching the edge of the membrane, and one by one to a vertical downward dip Hydrochloric acid solution into 0.5mol/L, at least 12h. Rinsed with pure water to neutral, sealed and set aside.

4.2 Description

4.2.1 standard blank (A0) and analysis of the blank (A Chou) deduction Save Ab calibration curve read or search curve, but only the same batch feasible; if the blank value (A0 and Ab) is very stable and can be extended by one week.

Note 1. Aw. water sample absorbance (signal) value;

Note 2. Ab. Analysis Blank absorbance values; Charles read the curve after Ab.

4.2.1.3 linear regression equation above provisions shall also be.

4.2.1.4 atomic absorption determination of gas chromatography, electrochemistry, with reference to the above provisions.

4.2.2 Error correction salt Salt error (error caused by different ionic strength) correction, application of clean seawater dilution volume standard series; if using pure water should be given Correction factor; known that certain correction factor (such as silicon, ammonia) subject to environmental impact and water fluctuations, the user should be based on measured results as necessary Correction.

4.2.3 Water sample volume correction When the amount of water samples taken before the sample is added to the aqueous reagent solution than 1% by volume, according to equation (1) Volume Correction. Vp = Vp

5.1 Atomic Fluorescence Spectrometry

5.1.1 Scope and Application Suitable for ocean, coastal and estuarine area measuring mercury in seawater. This method is a method of arbitration.

5.1.2 The principle of the method Water samples by sulfuric acid - potassium persulfate digested, potassium borohydride reducing agent in the role of mercury ions are reduced to elemental mercury. With argon as a carrier Gas mercury vapor atomic fluorescence spectrometer into the atomizer, with special mercury hollow cathode lamp as the excitation source, the determination of mercury atomic fluorescence strength.

5.1.3 Reagents and preparation

5.1.3.1 Sulfate. technology ultrapure, rho = 1.84g/mL.

5.1.3.2 Nitrate. excellent pure, rho = 1.42g/mL.

5.1.3.3 hydroxylamine hydrochloride (NH2OH · HCl).

5.1.3.4 potassium persulfate (K2S2O8).

5.1.3.5 potassium borohydride (KBH4).

5.1.3.6 potassium hydroxide (KOH). pure class distinctions.

5.1.3.7 hydroxylamine hydrochloride solution (100g/L). Weigh 25g hydroxylamine hydrochloride (see 5.1.3.3) was dissolved in water and dilute to 250mL.

5.1.3.8 persulfate solution (50g/L). Weigh 50g of potassium persulfate (see 5.1.3.4) dissolved in water and diluted to 1000mL.

5.1.3.9 sulfuric acid solution. Under stirring, 28mL sulfuric acid (see 5.1.3.1) is slowly added 500mL of water, diluted To 1000mL.

5.1.3.10 nitric acid solution (1 + 19). A 50mL nitric acid (see 5.1.3.2) slowly added to 1000mL water.

5.1.3.11 KBH4 solution (0.05g/L). Weigh 1g of potassium hydroxide (

5.1.3.6 The) was dissolved in 200mL of water was added 0.5g borohydride Potassium (see 5.1.3.5) dissolved, take 20mL diluted with water to 1000mL.

5.1.3.12 mercury standard stock solution (1.00mg/mL). Weigh accurately 0.1354g mercury (HgCl2, excellent pure chloride, sulfuric acid previously dry Dryer placed 24h or more) in 50mL clean beaker, dissolved with a small amount of nitric acid solution (see 5.1.3.10), the total amount transferred 100mL flask with a nitric acid solution (see 5.1.3.10) set the volume to the mark, and mix.

5.1.3.13 mercury intermediate standard solution (10.0µg/mL). Pipette 1.00mL mercury standard stock solution (see 5.1.3.12) into 100mL Flask, add nitric acid solution (see 5.1.3.10) to the mark and mix.

5.1.3.14 mercury intermediate standard solution (0.100µg/mL). Pipette 1.00mL mercury intermediate standard solution (see 5.1.3.13) into 100mL Flask, add nitric acid solution (see 5.1.3.10) to the mark and mix.

5.1.3.15 use mercury standard solution (10.0ng/mL). Pipette 10.00mL mercury intermediate standard solution (see 5.1.3.14) into 100mL Flask, add nitric acid solution (see 5.1.3.10) to the mark, and mix (when using the formulation).

5.1.4 instruments and equipment Instruments and equipment are as follows:

--- Atomic fluorescence spectrometer;

--- Volumetric flask. capacity 100mL, 1000mL;

--- Pipette. Volume 1mL, 2mL, 5mL, 10mL;

--- Beaker. Capacity 50mL, 1000mL;

--- Standing general laboratory instruments and equipment.

5.1.5 Analysis of step

5.1.5.1 standard curve 5.1.5.1.1 measure 0mL, 0.25mL, 0.50mL, 1.00mL, 2.00mL, 4.00mL, 8.00mL mercury standard solution (see 5.1.3.15), were transferred to 100mL volumetric flask, add sulfuric acid solution (see 5.1.3.9) to the mark and mix. Respectively, injection 2.0mL, according to Regression coefficients, the results recorded in Table A. 1.

5.1.5.2 sample determination 5.1.5.2.1 sample digestion. Measure 100mL water sample in 250mL conical flask, 2.0mL sulfuric acid (see 5.1.3.1), 5.0mL Potassium persulfate solution (see 5.1.3.8), left at room temperature to digest 24h, or heated to boiling after 1min, cooled to room temperature, a solution of 2mL salt Acid hydroxylamine solution (see 5.1.3.7), mix this solution as the sample digest. 5.1.5.2.2 Analysis Blank. amount of mercury-free water to 250mL 100mL conical flask, 2.0mL sulfuric acid (see 5.1.3.1), 5.0mL potassium persulfate solution (see 5.1.3.8), placing more than 24h digestion at room temperature or heated to boiling after 1min, cooled to room temperature, 2mL solution of hydroxylamine hydrochloride solution (see 5.1.3.7), mix this solution for the analysis of blank solution. 5.1.5.2.3 were taken 2.0mL sample digestion (see 5.1.5.3.1) and analysis of the blank solution (see 5.1.5.3.2) in the hydride generator The blank fluorescence intensity was measured (Ib) and the sample digest fluorescence intensity (Is). In (Is-Ib) values obtained from the standard curve the amount of mercury (ng), Or with a linear regression equation calculated the amount of mercury (ng).

5.1.6 recording and computing The sample measurement data recorded in Table A. 2, according to equation (2) calculation of mercury content in seawater. (2) Where.

--- Ba concentration of mercury in water, in units of micrograms per liter (µg/L); K

--- after sample digestion volume correction factor of 1.09; Vp

--- injection volume in milliliters (mL).

5.1.7 precision and accuracy Concentration of 1.00µg/L, the relative standard deviation of 2.5% repeatability; reproducibility relative standard deviation of 10.2%; relative error of 6.5%.

5.1.8 Precautions The method implementation should note the following.

--- Unless otherwise indicated, the methods used were of analytical grade reagents and water for the mercury-free water or equivalent water.

--- After all the utensils used for testing must be soaked in a solution of nitric acid (1 + 3) in 24h, rinsed with deionized water before use;

--- Do not allow the vessel during the test by mercury contamination. The mercury content greater difference

--- hydroxylamine hydrochloride, reagent blank should be tested before use, so as to avoid blank value is too large, resulting in an excessive measure Fixed error.

--- Due to factors affecting the determination of mercury more, as the carrier gas flow rate, a mercury lamp current, negative high voltage, etc. Therefore, in each case measured standard assays series.

5.2 cold vapor atomic absorption spectrophotometry

5.2 Cold atomic absorption spectrophotometry

5.2.3.1 Potassium persulfate (K2S2O8)

5.2.3.2 anhydrous calcium chloride (CaCl2). For loading drying tube.

5.2.3.3 Low mercury sea. surface waters through a filter paper, the mercury content should be less than 0.005µg/L.

5.2.3.4 nitric acid solution (1 + 19). A 50mL nitric acid (rho = 1.42g/mL) was slowly added to 1000mL water.

5.2.3.5 sulfuric acid solution (1 + 1). A 500mL sulfate (rho = 1.84g/mL) was slowly added to 500mL of water.

5.2.3.6 sulfuric acid solution (0.5mol/L). under agitation 28mL sulfuric acid (rho = 1.84g/mL) was slowly added to water, and dilute to 1L.

5.2.3.7 hydrochloric acid solution (1 + 1). diluted hydrochloric acid (rho = 1.19g/mL) with an equal volume of water.

5.2.3.8 hydroxylamine hydrochloride solution (100g/L). Weigh 25g of hydroxylamine hydrochloride (NH2OH · HCl) was dissolved in water, and dilute to 250mL.

5.2.3.9 Stannous chloride solution. Weigh 100g stannous chloride (SnCl2) in the beaker, 500mL of hydrochloric acid solution (see 5.2.3.7), Heated to completely dissolve the stannous chloride, cooled to prosper in the reagent bottle. Diluted with an equal volume of water just before using. Mercury impurities is high, in addition to nitrogen gas Mercury until the mercury content undetectable.

5.2.3.10 mercury standard stock solution (1.00mg/mL-Hg). Weigh 0.1354g mercuric chloride (HgCl2, previously dry in sulfuric acid desiccator Dry) in 10mL beaker with a solution of nitric acid (see 5.2.3.4) was dissolved, the total amount transferred to 100mL flask, was added nitric acid (see 5.2.3.4) diluted to the mark, and mix. Sheng in brown borosilicate glass vial, the solution can be stored for one year.

5.2.3.11 mercury intermediate standard solution (10.0µg/mL). Pipette 1.00mL mercury stock standard solution (see 5.2.3.10) in 100mL amount Flask, add nitric acid solution (see 5.2.3.4) diluted to the mark, and mix. This solution may be held on the week.

5.2.3.12 use me...