Question

How would you carry out the following analysis. Give all the necessary steps required and also mention your choice of instruments. a. Hg contamination in a river. b. Parts per trillion level of Pb in drinking water. c. PAH in river water. d. Gasoline contamination in ground water.

This is an analytical chemistry question.

Answer 1

Answer Page No:1 * We have to implement the following analysis, all the necessary steps are required & mention the chorce of instruments. Q. Hg contamination in riceer beparto per tretfron level of pb in drinking water C PAH in Muer water di Gasoline contarmination in ground water a. Ha contamination in tfuer # The water sample containing mercury is dugested with Husou * kMnoy solution to obtain a free Hg fon. * Excess kirnou fs removed by adding hydroxylamine and reducing coith stannous chloride. * Atomic Absorption Spectroscopy is deter wed to determined, tr standard solution of Hg is prepared & standard Curte is obtained. & Now take absorbance of the sample and calculate the concentration Standard curue is calculated by 14 = mx tb where yo ug Hq x -area m = slope CS Camscaba intercept CamScanner

Page No:2 * calculate m and b the calculate ug HQ in Sample and druide by Sample cot in grams to obtain ppm. Bi parts per trillion level of pb in drinking 440:- * Standard of lead nitrate was prepared in defonſzed to * The Series of standard sample was mixed with dithfzone solution and then cetyltrimethylammonium bromide. (CTAB) * This mixture is diluted & absorbance is measured at 500 nm against blank: * Draw callibration graph * Take absorbance of sample (unknown) & then plot absorbance in standard. curve. Calculate Conantrafron by A- ect] c. PAH in river water * The Standard was used as chrysene solution and the extract was analyzed in au- fleroscence Spectroscopy at 310 nm excitafton wauelength & intensitt's were measured at 360 nm. # PAM from river water samples fdentify and quantify the indfurdual compounds. * An optimized reverse solid phase extraction method coas cesed after condiffoning the sorbent to extract and preconcentrate the compounds of PAH in river water sample. Scanned with

Page No :3 d. Gasoline contamination in ground water * Be sure to take a representatrie sample * Make sure Sample bottles are properly rinsed filter and presenle samples in field. * Fabe field Measurements with proper equipment of send to a certified water chemistry Lab corthin - 24 hours of sampling * Have a quality control program with duplicates, blants, freed blanks or spiced samples. Sampling Methods e Samplong wells with in-place plumbing 2. sampling wells worfroct place plumbing . copfhin the - limit of suction 3. Sampling wells Exceeding the comit of suceron only Es Micro-purge 160- purge Sampling procedures. CamScanner