Some standard content:
National Standard of the People's Republic of China
Analytical method of nickel-63 ln water
Analytical method of nickel-63 ln water1 Subject content and scope of application
This standard specifies the analytical method of nickel-63 in water. GB/T14502-93
This standard is applicable to the analysis of nickel-63 in surface water, groundwater, drinking water and wastewater discharged from nuclear facilities. Determination range: 4.1×10-2~20g/l.
2 Reference standards
GB12379 Environmental nuclear radiation monitoring regulations
3 Method summary
Add nickel carrier to the water sample and precipitate concentrated nickel-63 in the form of hydroxide. Use tri-n-octylamine extraction and butanone complexation to separate nickel-63 from cobalt-60, zinc-65, iron-55 and other activation products and constant ions such as calcium and magnesium, and finally dissolve it with hydrochloric acid and measure it by liquid scintillation counting. 4 Reagents
All reagents are analytically pure reagents and distilled water or water of equivalent purity that meet national or industry standards. The radioactivity of reagents and water must ensure that the counting rate measured by the blank sample is within the statistical error of the background of the liquid scintillation counter. 4.1 Sodium hydroxide solution (Na0H) = 10 mol/l. 4.2 Hydrochloric acid, HCI content 36%~38%. 4.3 Hydrochloric acid solution: c(HCI)n.1 mol/L..4.4 Acetic acid solution: r:(HCI) = 1.0 mrl/L. 4.5 Ammonium hydroxide: NH,OH content 25%~28%. 4.6 Ammonium hydroxide solution: pH8~9.
4.7 Tri-n-octylamine rCH,(CH,),J,N-toluene solution: 5% (V/V) 4.8 Ammonium hydroxide-ethanol solution: pH8.
4.9 Dimethylformamide solution: 10 g/L. Weigh 10.0 g of diacetyl (C,HN,0, content not less than 97.0%) and dissolve it in 100 mlL ammonium hydroxide-ethanol solution (4.8), transfer it into a 1 L volumetric flask, and dilute it to the mark with ammonium hydroxide-ethanol solution (4.8). 4.10 Perchloric acid: IIC10. Content 70.0%~-72.0%, 4.11 Scintillation liquid: Take 6.1 g of 2,5-dimethylaminobenzoic acid [OC(CsH)=CHN=CCHsPPO, scintillation pure and 0.3 g of 1,4-bis(5-phenyltazazolyl-2)benzene (OC(CHs)=CHN=CCH,POPOP scintillation pure) and 100 g of CH. Dissolve it in 1,1-oxahedral (C,H,)O1, and dilute to 1 L, store in a brown bottle in a dark place. 4.12 Nickel-63 standard solution: about 300 Bq/tng, total viscosity ±3 yuan. 4.13 Nickel carrier solution: 10 mgNi/mL
4.13.1 Preparation: Weigh 40.5 g nickel chloride (NiCl,*6H.0) and dissolve it in 100 mL hydrochloric acid solution (1.3)1, transfer to a volumetric flask, and dilute with hydrochloric acid solution (4.3) to standard solution. 4.13.2 Calibration:
GB/T 14502-93
Put six portions of 1.00 mL nickel carrier solution (4.13.1) in 100 mL centrifuge tubes respectively, adjust the solution to pH 8-9 with ammonium chloride (4.5), then add 10 mL of butanone solution (4.9), mix, heat in 90-95°C water for 10 min, cool and centrifuge, remove the supernatant, wash the precipitate with ammonium hydroxide-ethanol solution (1.8), 15 mL each time, and then filter with a removable funnel. Dry the precipitate at 110°C for 2 h, weigh to constant weight, and calculate the nickel content. 5 Apparatus and equipment
5.1 Liquid flash counter: The background count rate is not less than 0.5 counts/s, and the counting efficiency for nickel-63 is not less than 30%. 5.2 Detachable funnel.
5.3 Oven.
5.4 Centrifuge,
5.5 Analytical balance: sensitivity 0.1mg
5.6 Electric stirrer.
6 Sampling
Perform according to the provisions of GB12379,
7 Analysis steps
7.1 Take 1~10% of water sample, add sodium hydroxide solution (4.1) to adjust to pH 7. Add nickel carrier solution (4.13) at a ratio of 1mg per liter of water sample, and slowly add sodium hydroxide solution (4.1) at a ratio of 0.7ml per liter of water while stirring at a speed of 1000r/min. Continue stirring for 0.5 h after addition. Let stand for 15 h 7.2 Discard the supernatant. Transfer the precipitate to a centrifuge tube and centrifuge at 2500r/min for 10min. Discard the supernatant. Dissolve the precipitate with 5mL hydrochloric acid (4.2) and transfer to a beaker. Wash the centrifuge clear solution three times with 15mL hydrochloric acid solution (4.4) and combine in the above beaker. Evaporate slowly on an electric sand bath. Dissolve the residue with 5mL hydrochloric acid (4.2) and transfer to 15ml tube several times. Extract the above solution with 5tml tri-n-octylamine-toluene solution (4.7) three times in total, oscillating for 3 minutes each time. Discard the organic phase. Transfer the aqueous phase to 50
7.4 Adjust the pH of the water to 89 with ammonium hydroxide (4.5). Stir well and place for 0.5h. Centrifuge at 2500r/min for 10min: transfer the supernatant to another 50ml centrifuge tube, wash the precipitate with ammonium hydroxide solution (4.6), centrifuge, close the supernatant and discard the precipitate.7.5 Add 10ml of dione solution (4.9) to the supernatant, heat in a 90~95 water bath for 10min, cool and centrifuge at 2500r/min for 10min, discard. Let the supernatant condense, then wash the precipitate three times with ammonium hydroxide-ethanol solution (4.8), 15min each time ml. Centrifuge. Discard the supernatant. Dissolve the precipitate with 1 ml of hydrochloric acid (4.2). Add 1 ml of perchloric acid (4.10) and keep it in an electric sand bath to keep it boiling for 0.5 h, then slowly evaporate it to dryness. Dissolve the above residue with hydrochloric acid solution (4.3) and transfer it to a 10 mL volumetric flask. Dilute it to the mark with hydrochloric acid solution (4.3). 7.6 Take 2.00 ml of this solution and put it into a 20 ml counting bottle. Add 16.0 ml of scintillation liquid (4.11). After protecting from light for 2 h, use a liquid scintillation counter (5.1) to measure the counting rate of nickel-63. 7.7 Take another 5.00 mL of the batch solution and put it into a 50 ml centrifuge tube. Add ammonium hydroxide (4.5) dropwise to pH 8~-9. Then add 5 mL of dibutyl bis(II) solution (4.9) and heat it in a 90~95°C water bath for 15 min. min, cool and centrifuge, discard the clear solution. Wash the precipitate with ammonium hydroxide-ethanol solution (4.8) for 15 ml each time. Then filter with a detachable funnel, dry the precipitate at 110 °C for 2 h, weigh it to calculate the chemical recovery rate of nickel. B. Measurement of counting efficiency
Take 1.90 mL of solution and 2.00 mL of distilled water from a 10 mL volumetric flask (7.5) and put them into two 20 mL counting flasks, add 0.10 and 0.0 mL of nickel-63 standard solution (4.12) and 16.00 mL of scintillator (4.11) respectively. Protect from light for 2 h. Measure the counting rates of the above samples and calculate their counting efficiencies.
9 Calculation of analysis results
GB/T 14502-93
-Radioactivity concentration of nickel-63 in water sample, q/; C-
N—Net counting rate of nickel-63, counts/s, counting efficiency of nickel-63;
F—Chemical recovery rate of nickel-63,
Vwater sample volume,.
10 Calculation of precision
This precision test number was determined in 1991 by three laboratories in an experiment on four and a half samples of water. The precision of the wood test method is as follows:
Horizontal range
0, 041~ 19. 897
Repeatability+www.bzxz.net
r =0, 093=0. 180 4 m
Reproducibility
R-0. 0560.228 2 m
GB/T 14502—93
Appendix A
Instructions for the correct use of the standard
(reference)
A1 When ammonium hydroxide is added to the raffinate aqueous phase, in addition to the formation of Ni(NH)++, Ca(OH) and Mg(OH) precipitates, a large amount of ammonium chloride will be precipitated due to the ionization effect, but the speed is slow. Therefore, it must be fully stirred and left for half an hour, otherwise it will hinder the next step. A2 When heating butanedione nickel precipitation, in order to prevent the butanedione nickel from being taken out of the centrifuge tube due to the boiling of ethanol, it must be stirred continuously during heating. In addition, the heating temperature shall not exceed 95℃ and the heating time shall not exceed 10min to prevent butanedione from precipitating. A3 After using percyanic acid to destroy butanedione, the perchloric acid must be completely driven out. A4 This standard can also use Iritonx-100 flash liquid, the formula is 8.0g PPC, 0.20g POPOP dissolved in Iriton-toluene (V/V12.75) solution, and diluted to 1L, stored in a brown bottle. Use in dark place. When using, be sure to mix the scintillation liquid and sample evenly.
A5 If the calcium and magnesium content in the water sample is less than 80mg/l., calcium chloride (or magnesium fluoride) needs to be added. Additional explanation for this value:
This standard was proposed by China National Nuclear Corporation. This standard was drafted by China Institute of Atomic Energy. The main drafter of this standard is Yu Yaoxian.
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