Contents to Volume

Prepare a 1000 ugmL individualherbicidesolutionby weighing 0.1000 0.0010 g (weight adjusted for purity) of each analytical-grade herbicide into individual 100-mL volumetric flasks, dilute the contents to volume with absolute ethanol, and mix the solution to ensure complete dissolution. Mix and dilute individual herbicide solutions to prepare a 100.0 ugmL mixed herbicide solution (for extended standards), a... 

Accurately weigh 0.1 g of the sample in a thoroughly cleaned quartz dish and add 1 mL of 6N nitric acid. Evaporate to dryness at 60-80°C, transfer the dish to the low temperature ashing equipment and ash for 12-18 h at a power of 250-300 watts. Treat the residue with 5 mL of 3N nitric acid and heat on a water bath for 10 min. Cool and make up the contents to volume in ultrapure water. 

For wet ashing of the dentin, transfer the weighed sample to a Kjeldahl flask and treat with 3 mL of 2 1 mixture of suprapure nitric acid (65% v/v) and perchloric acid (63% v/v). Digest slowly at a low heat initially and then raise the temperature to 180°C till a clear solution is obtained and the white fumes are given off. Cool and dilute the contents to volume with ultra-pure water. The solution can be used for determination of major, minor and trace elements including iron, lead, manganese, zinc, tin, barium, cadmium, copper, vanadium, strontium and the rare earths using F-AAS, F-AES, and ICP methods. 

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