Embodiment
The sample of embodiment is a pure selenium, is that the purity that made through further purifying by cathode copper, the plumbous earth of positive pole and the comprehensive selenium raw material that reclaims of waste materials such as the flue dust of sulfuric acid plant, sour mud is at the selenium more than 99%.Choose two kinds of different samples, be respectively sample 1# and 2#, each embodiment by same procedure measure sample 1# and 2# selenium each once.
Embodiment 1
Take by weighing the 0.50g sample and place 250mL beaker (doing blank test) in company with sample, wetting with low amounts of water, add the 2mL red fuming nitric acid (RFNA), the low-grade fever dissolved samples.Add the 20mL concentrated hydrochloric acid, heating makes sample dissolution, takes off cold slightly.Adding water to volume is 60mL, adds the 25mL concentrated hydrochloric acid again, is heated to and boils.Take off coldly slightly, add 7g hydroxylamine chloride, 2g ascorbic acid, stir and make the selenium precipitation separate out and condense.Place boiling water bath to leave standstill 2h in beaker, after the cooling test solution is changed in the 100mL volumetric flask, the simple substance selenium of cohesion can be stayed in the beaker, is diluted to scale with water, mixing.
Branch is got the 20mL test solution and is placed the 150mL beaker, adds 1mL1: 1 sulfuric acid: water, and be heated to and just emit the white cigarette of sulfuric anhydride, take off cooling.Add low amounts of water and boil, change over to after the cooling in the 50mL volumetric flask, add the 6mL50g/L thiocarbamide: 50g/L ascorbic acid mixed solution, be diluted with water to scale, mixing is placed 20min.Sulfuric acid with 1: 99: water is made current-carrying, and the 25g/L solution of potassium borohydride is a reductive agent, measures its fluorescence intensity on atomic fluorescence spectrometer, deducts the fluorescence intensity in company with the sample blank testing liquid, calculates the mass concentration of tin with calibration curve method.
Embodiment 2
Take by weighing the 1.00g sample and place 250mL beaker (doing blank test) in company with sample, wetting with low amounts of water, add the 3mL red fuming nitric acid (RFNA), the low-grade fever dissolved samples.Add the 20mL concentrated hydrochloric acid, heating makes sample dissolution, takes off cold slightly.Adding water to volume is 60mL, adds the 30mL concentrated hydrochloric acid again, is heated to and boils.Take off coldly slightly, add 8g hydroxylamine chloride, 2g ascorbic acid, stir and make the selenium precipitation separate out and condense.Place boiling water bath to leave standstill 1.5h in beaker, after the cooling test solution is changed in the 100mL volumetric flask, the simple substance selenium of cohesion can be stayed in the beaker, is diluted to scale with water, mixing.
Branch is got the 10mL test solution and is placed the 150mL beaker, adds 1mL1: 1 sulfuric acid: water, and be heated to and just emit the white cigarette of sulfuric anhydride, take off cooling.Add low amounts of water and boil, change over to after the cooling in the 50mL volumetric flask, add 4mL 50g/L thiocarbamide: 50g/L ascorbic acid mixed solution, be diluted with water to scale, mixing is placed 25min.Sulfuric acid with 1: 99: water is made current-carrying, and the 30g/L solution of potassium borohydride is a reductive agent, measures its fluorescence intensity on atomic fluorescence spectrometer, deducts the fluorescence intensity in company with the sample blank testing liquid, calculates the mass concentration of tin with calibration curve method.
Embodiment 3
Take by weighing the 1.00g sample and place 250mL beaker (doing blank test) in company with sample, wetting with low amounts of water, add the 4mL red fuming nitric acid (RFNA), the low-grade fever dissolved samples.Add the 20mL concentrated hydrochloric acid, heating makes sample dissolution, takes off cold slightly.Adding water to volume is 60mL, adds the 20mL concentrated hydrochloric acid again, is heated to and boils.Take off coldly slightly, add 9g hydroxylamine chloride, 2g ascorbic acid, stir and make the selenium precipitation separate out and condense.Place boiling water bath to leave standstill 2h in beaker, after the cooling test solution is changed in the 100mL volumetric flask, the simple substance selenium of cohesion can be stayed in the beaker, is diluted to scale with water, mixing.
Branch is got the 5mL test solution and is placed the 150mL beaker, adds 1mL1: 1 sulfuric acid: water, and be heated to and just emit the white cigarette of sulfuric anhydride, take off cooling.Add low amounts of water and boil, change over to after the cooling in the 50mL volumetric flask, add 8mL 50g/L thiocarbamide: 50g/L ascorbic acid mixed solution, be diluted with water to scale, mixing is placed 30min.Sulfuric acid with 1: 99: water is made current-carrying, and the 20g/L solution of potassium borohydride is a reductive agent, measures its fluorescence intensity on atomic fluorescence spectrometer, deducts the fluorescence intensity in company with the sample blank testing liquid, calculates the mass concentration of tin with calibration curve method.
Table 1 is result's contrast of measuring tin in the sample with method of the present invention and industry standard YS/T226.3-1994 analytical approach.As can be seen from Table 1, this law result and rower methods and results basically identical.
The result that table 1 is measured trace tin in the selenium compares
Because a large amount of matrix selenium produce seriously Determination of Microamount of Tin and disturb, therefore need to separate except that selenium.Table 2 has provided embodiment 2 behind the reduction separating step, and selenium amount remaining in the test solution is removed main element selenium the correlation data of the remaining selenium amount in back with adopting the industry standard method with the volatilization of SeO2 form in 320 ℃ of selenium volatilization stoves.By table 2 as seen, the separating effect of this law is better than the rower method.
The remaining selenium amount of table 2
Table 3 has provided the mark-on recovery test result of the inventive method, adds the tin standard of different amounts respectively in the 1# sample, measures by the method for embodiment 3.By table 3 as seen, method recovery of standard addition of the present invention is between 97.9~102.7%, accurately and reliably.
Table 31# sample mark-on recovery test
Table 4 has provided the Precision test result of method, presses the method for embodiment 2,1#, 2# sample is carried out 9 times respectively measure the relative standard deviation of computing method, the stability of investigation method and reappearance.Data presentation, the relative standard deviation of this law is less, and method is stable, favorable reproducibility.
The test of table 4 precision
Comprehensive above data as seen, method of the present invention be the residual quantity of a kind of matrix good separating effect, selenium little, do not use that harmful organic reagent, mensuration are highly sensitive, detection limit is less than 1 * 10
-9G/mL, easy and simple to handle, result accurately, the analytical approach of trace tin in the selenium of favorable reproducibility.Be applicable to and measure in the pure selenium 0.0002~0.01% tin content.