Preparation of standard series solution for atomic absorption spectrophotometer

Preparation of standard series solution for atomic absorption spectrophotometer

Six 50ml volumetric flasks were taken, and 1 g/ml Se was added accurately in turn, using standard solution 0, 0.5, 1.0, 1.5, 2.0, 2.5ml (each equivalent Se concentration 0, 10, 20, 30, 40, 50ng/ml), adding 1+1 hydrochloric acid 20ml, supplementing water to the scale, mixing and preparing.

Atomic absorption spectrophotometer manufacturer selenium is known as the "king of anti-cancer", is an essential trace element of human body, selenium can improve human immunity, promote lymphocyte proliferation and antibody and immunoglobulin synthesis. Selenium has obvious inhibitory and protective effects on colon cancer, skin cancer, liver cancer, breast cancer and other cancers, and its intermediate metabolite, methyl enol, has strong covering activity. Selenium and vitamin E, allicin, linoleic acid, germanium, zinc and other nutrients have synergistic antioxidant effect, increase antioxidant activity. At the same time, selenium can alleviate and alleviate the toxicity of heavy metals. Selenium resources are relatively scarce in China. At present, some Se-rich soil resources are found only in Jiangxi, Zhejiang, Hainan and Qinghai provinces.

Selenium-rich soil can cultivate Se-rich food, wheat, rice, corn, pepper and other soil easily absorb Se. Selenium content of rice in Se-enriched areas can reach 0.115 mg per kg, wheat can reach 0.104 mg, corn can reach 0.071 mg, apples, tomatoes, dates and other Se-enriched than rice, corn and other low.

Accurately take 0.5g soil sample into 100 ml PTFE digestion tank, add 10 ml concentrated nitric acid, 2 ml perchloric acid, 2 ml hydrofluoric acid, sealed and static overnight. The next day, the digestion tank was heated on an electric heating plate, and the temperature was controlled at about 200 oC. The digestion system was slightly boiling. Nitric acid was added several times during the heating process. After all the soil samples were dissolved, the color became light and the remaining 1-2 ml, the digestion was complete. After cooling to room temperature, add 25 ml deionized water to continue heating to remove acid. After remaining 1-2 ml of solution, cool to room temperature, transfer deionized water to 50 ml volumetric flask, add 2.5 ml hydrochloric acid, and fix the volume of deionized water. Sample blank is done in the same way.

Rice as an example

The appropriate amount of dried rice is crushed evenly, sealed and stored. About 1.0 g of rice sample powder (accurate to 0.001 g) was weighed in 50 ml plastic centrifugal tube, and 15 ml of nitric acid + perchloric acid (4 + 1) mixed acid was added to shake and soak evenly, and placed overnight. The next day, the digestive juice will be light yellow or colorless when heated on an electric heating plate (e. g. digestion process with a dark color, slightly cooled by adding a small amount of nitric acid, continue to digest). Add 25ml deionized water slightly and then continue heating, then remove the acid to 0.5~1.0ml. Cooling, using deionized water content into a 10 ml colorimetric tube or volume bottle, adding 1 + 1 hydrochloric acid 4.0 ml, water to the scale and mix, ready. Sample blank is done in the same way.

Manufacturers of atomic absorption spectrophotometer