Standard solutions of necessary concentration are prepared consecutive dilution in 10, 100 and 1000 times of the main solution of cadmium. At change of concentration of cadmium in the examinee solution dilution is carried out bidistillirovanny water.
Bring an additive in the second flask - standard solution in such, that pas cadmium peak height to a polyarogramma approximately in comparison with initial. The additive should be brought in small volume (no more than 1 cm to prevent change of concentration of background electrolyte and cindery elements. Then add background electrolyte or bidistillirovanny water to a flask (during the work with electrolyte in the volume necessary for finishing it to 5sm ³. Pass inert gas, polyarografirut in the same conditions and cadmium peak height.
Makes values of a mean square deviation of a casual component of an error of measurements of a mass fraction of zinc of the same test in different laboratories at the changes of the influencing factors allowed by a technique 0,14 X.
Take the arithmetic average (X) results of two parallel definitions allowed between which for final result should not exceed at P = 0,95 30% on an to an arithmetic average. The final result is rounded to the second decimal sign.
Standard solutions of necessary concentration are prepared in day of an consecutive dilution of the main solution of zinc in 10, 100 and 1000 times. At measurement of concentration of zinc in the examinee solution with use of background electrolyte A dilution is bidistillirovanny water.
The method is based on a dry mineralization (combustion) of test with use as a supportive application of nitric acid and quantitative definition of zinc a polyarografirovaniye in the mode of alternating current.
In the analysis of dairy products use background electrolyte A - the mixed solution about ortofosforny phosphoric acid C (H3PO = 1,3 mol/dm ³ and chloric acid C (HCl = 0,7 mol/dm ³: mix the diluted ortofosforny, chloric acids and bidistillirovanny water in the ratio 3:2:
The laboratory glasswares is washed out chromic mix,, nitric acid with a density of 1,40 g/cm3, several times and twice bidistillirovanny water and dried up. Then solution of a ditizon 0,01 g/dm Even at an insignificant of coloring carry out several times processing the ditizony: ware solution of a ditizon of 0,30 g/dm3 and maintain every time for 30 min. then wash out chloroform and repeat processing, solution of a ditizon of 0,01 g/dm
Bring an additive in the second flask - standard solution of zinc in quantity that zinc peak height on a polyarogramma approximately doubled in comparison with the initial. The additive should be brought in small volume (no more than 1 cm to prevent change of a of background electrolyte and cindery elements. Then in a flask bidistillirovanny water in the volume necessary for its to 10 cm Further arrive the same as with solution without additive.
Makes values of a mean square deviation of a casual error of measurements of a mass fraction of cadmium of the same test in different laboratories at the changes of the influencing factors allowed by a technique 0,22 X.
Definition is carried out as follows: go to two conic with a capacity of 10 25 cm3 place on 4 cm3 control or the Examinee of solution and add the minimum quantity of cadmium (0,2-0,5 which would provide on a polyarogramma of accurate peak of cadmium.