GB/T 4375.4-1984 Chemical analysis of gallium - 4,7-diphenyl-1,10-phenanthroline spectrophotometric method for determination of iron content GB/T4375.4-1984 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical analysis of galliumThe 4,7-diphenyl - 1,10 -phenanthrolinephotometric method for the determinationof iron content
This standard is applicable to the determination of iron in gallium. Determination range: 0.000050～0.015%. UDC 669.871 : 543
.42 :546.72
GB 4375.4--84
This standard complies with GB1467-78 "General Principles and General Provisions of Standards for Chemical Analysis Methods of Metallurgical Products". 1 Method Summary
The sample is dissolved in nitric acid and hydrochloric acid. Iron (III) was reduced with hydroxylamine hydrochloride, and the matrix gallium was masked with sodium citrate. Under the condition of pH 5-6, iron (II) and 4,7-diphenyl-1,10-phenanthroline formed a red complex, which was extracted with isoamyl alcohol and its absorbance was measured at a wavelength of 530nm on a spectrophotometer.
2 Reagents
2.1 Anhydrous ethanol, high-grade purity.
2.2 Isoamyl alcohol.
Ammonium hydroxide, high-grade purity.
Nitric acid, purified by distillation at 120℃.
2.5 Hydrochloric acid, purified by sub-boiling distillation.
2.64,7-phenyl-1,10-phenanthroline anhydrous ethanol solution (0.2%). 2.7 Hydroxylamine hydrochloride solution (20%): Weigh 100g of hydroxylamine hydrochloride and 25g of anhydrous sodium acetate, place in an 800ml beaker, dissolve in water and dilute to 500ml, heat in a water bath to 80-90℃, add 10ml of 4,7-diphenyl-1,10-aza-non solution (2.6) and 10ml of anhydrous ethanol (2.1), stir with a glass rod, keep warm in a water bath for 20min, remove and place for more than 4h. Transfer the solution to a 1000ml separatory funnel, add 30ml of isoamyl alcohol (2.2), shake vigorously, let stand and separate, and discard the organic phase. Repeat this operation until the organic phase is colorless. Transfer the aqueous phase to a polyethylene bottle for storage. 2.8 Sodium citrate solution (30%): Weigh 150g sodium citrate and 2g hydroxylamine hydrochloride, place in an 800ml beaker, dissolve in water and dilute to 500ml, proceed as described for hydroxylamine hydrochloride solution (2.7), starting from heating in a water bath to 80-90℃. If the iron content is too high, perform another purification operation. 2.9 Thiourea solution (10%): Weigh 10g thiourea in a 250ml beaker, dissolve in water and dilute to 100ml, proceed as described for hydroxylamine hydrochloride solution (2.7), starting from heating in a water bath to 80-90℃ [the amount of 4,7-diphenyl-1,10-phenanthroline solution (2.6) and isoamyl alcohol (2.2) is changed to 5ml and 15ml respectively]. 2.10 Iron standard stock solution: Weigh 1.000g pure iron (99.9% or more), place in a 400ml beaker, add 30ml nitric acid (1+1), dissolve, heat to remove nitrogen oxides, cool, transfer to a 1000ml volumetric flask, dilute with water to scale, mix. This solution contains 1.0mg iron per ml.
National Bureau of Standards 1984-04-30 Issued
1985-04-01 Implementation
GB4375.4—84
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2.11 Iron standard solution: Transfer 10.00ml iron standard stock solution (2.10), place in a 100ml volumetric flask, dilute with water to scale, mix. This solution contains 100μg iron per ml. 2.12 Iron standard solution: Pipette 10.00 ml of the iron standard solution (2.11) into a 100 ml volumetric flask, dilute to the mark with water, and mix. This solution contains 10 μg of iron per ml.
2.13 Iron standard solution: Pipette 10.00 ml of the iron standard solution (2.12) into a 100 ml volumetric flask, dilute to the mark with water, and mix. This solution contains 1 μg of iron per ml.
3 Instruments and apparatus
3.1 Spectrophotometer.
8.2 Quartz beaker.
4 Analysis steps
4.1 Determination quantity
Weigh two samples for determination and take the average value. 4.2 Sample quantity
Weigh the samples according to Table 1.
0.000050~0.00030
>0.00030 ~0.0015
>0.0015~0.015
4.3 Air test
Carry out the sound test together with the sample. bZxz.net
Nitric acid amount
Hydrochloric acid amount
Solution amount
Hydroxylamine hydrochloride
Solution amount
Sodium citrate
Solution sensitive
Isoamyl alcohol amount
Absolute ethanol
The volume after dilution!
Working curve
Iron range
0～ 10
0～30
4.4 Determination
4.4.1 Place the sample (4.2) in a 50ml quartz beaker, add nitric acid (2.4) according to Table 1, cover with table III, place on an electric furnace to warm until the sample is dispersed and then remove. Add hydrochloric acid (2.5) according to Table 1, after the violent reaction stops, place the beaker on an electric furnace and heat until the sample is completely dissolved. Raise the temperature of the electric furnace to about 160℃, and concentrate the solution to about one tenth of the original volume. Remove the beaker, rinse the table and the wall with about 5ml of water, and cool.
4.4.2 Add thiourea solution (2.9), hydroxylamine hydrochloride solution (2.7), and sodium citrate solution (2.8) according to Table 1. Mix each reagent well and dilute with water to about 30ml. 4.4.3 Adjust the solution to pH 5-6 with ammonium hydroxide (2.3), heat it to 80-90°C on a water bath, add 2 ml of 4,7-phenyl-1,10-phenanthroline solution (2.6) and 5 ml of anhydrous ethanol (2.1), mix them. Keep it warm on a water bath for about 10 minutes, remove it and cool it down.
4.4.4 Transfer the solution (4.4.3) to a separatory funnel, wash the cup with about 1 ml of anhydrous ethanol (2.1), and then wash the cup with a little water several times and add the washing liquid to the separatory funnel. 4.4.5 Add according to Table 1 Isoamyl alcohol (2.2), shake vigorously for 1 minute, let stand to separate, and discard water. Add 5 ml of water to the organic phase, shake at 285 °C for 30 seconds to wash the organic phase, let stand to separate, discard the aqueous phase, and repeat this operation: - times. 4.4.6 Transfer the organic phase to a colorimetric bomb and dilute it with water and ethanol (2.1) according to Table 1. 4.4.7 Transfer part of the solution (4.4.6) to a 11 cm colorimetric tank, use isoamyl alcohol (2.2) as a reference, and measure its absorbance at 530 nm on a spectrophotometer. 1 Find the corresponding iron content on the curve. 4.51 Draw the curve
4.5.1 When the iron content is 0.000050~0.00030%, transfer 0, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00 ml of the iron standard solution (2.13); when the iron content is 0.00030~0.0015%, transfer 0, 0.20, 0.40, 0.60, 0.80 ml of the iron standard solution (2.12); when the iron content is 0.0015~0.015%, transfer 0, 0.50, 1.00, 1.50, 2.00, 3.00 ml of the standard iron solution (2.12) are placed in a set of 50 ml beakers respectively, and the following is carried out according to 4.4.2 to 4.4.6. 4.5.2 Pipette part of the solution (4.5.1) into 1 cm colorimetric tube, use isoamyl alcohol (2.2) as reference, measure its absorbance at a wavelength of 530 nm with an electron spectrophotometer, and draw a curve with iron content as the horizontal axis and absorbance as the vertical axis. Calculation of analysis results
Calculate the iron content according to the following formula:
Fe(）-
mo× 10h
武：m2—the amount of iron in the sample solution obtained from the curve 1, g; m,—the amount of iron in the empty solution accompanying the sample obtained from the curve 1, ug; m----sample u, g.
6 Tolerance
The difference between the analysis of laboratories should not be large. The tolerance listed in Table 2 Table 2
0. 00005 ~ 0. 00020
0. 00020 ~ 0. 00080
6.0008 ~0.00120
0. 0020 ~ 0. H150
0.005~0.015
Additional Notes:
This standard was proposed by the Nonferrous Metals Industry Corporation. The Nonferrous Metals Research Institute of the Nonferrous Metals Industry Corporation was responsible for drafting this standard. The main author of this standard was Liu Kalong.
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