Part I. Problem solving. Include all necessary calculations 13 provide plots and graphs. Complexation wl diphenyl carbazide (OPC) in acidic media is another type of sensitive photometric method used for the analysis of aqueous. hexavalent chromium. At 540nm the cherry-red complex as a result of DPC reaction w/ chromium can be photometrically measured. at this wavelength. - a 25mL The UV-vis analysis for the determination of nexavalent chromium in ground water sample is given below. The experiment was based on external calibration method w/ each measurement sample prepared are as follows lab sample analysis contained the standard 100 ppb croy cor groundwater sample, volumes used as indicated below), 12.50 mL of 0.02 M H2Soy and 5.50 ml of 100 ppm DPC (wi water to adjust final volume to 25-ml). The main stripping method was square wave voltammetry, following the conditions set in the main ASV experiment. Standard 100 Volumetric Groundwater H2SO4 0.20 M, flask Sample, mL ppb CrO4*, 100 ppm DI H₂O, Absorbance mL DPC, mL mL mL 1 0.00 0.00 12.50 5.50 7.00 0.001 2 0.00 0.00 12.50 5.50 7.00 0.002 3 0.00 0.00 12.50 5.50 7.00 0.004 4 0.00 2.50 12.50 5.50 4.50 0.467 5 0.00 2.50 12.50 5.50 4.50 0.435 6 0.00 2.50 12.50 5.50 4.50 0.397 7 0.00 5.00 12.50 5.50 2.00 0.881 8 0.00 5.00 12.50 5.50 2.00 0.873 9 0.00 5.00 12.50 5.50 2.00 0.821 10 5.00 0.00 12.50 5.50 2.00 0.211 11 5.00 0.00 12.50 5.50 2.00 0.289 12 5.00 0.00 12.50 5.50 2.00 0.199 13 5.00 0.00 12.50 5.50 2.00 0.233 14 5.00 0.00 12.50 5.50 2.00 0.223 a) what is the mean absorbance values for the solutions of: 1) blank 2) 2.50ml Croy standard added 3) 5.00 ml croy 11 11 4) J.00 ml samples added b) Find the least-squares best line through the points of 0.00ml added, 2.50 ml added, 5.00 ml added croy' standards. Find the calibration sensitivity. c) Determine standard deviation of the blank & blank d) what is the LOD nd LOQ of the analysis. what does this values refer to? e) Give the residual plot for the calibration plote, showing each point used in the calibration curve. Determine SCV) f) Determine the standard deviation of groundwater analysis syo based on calibration curve. Show solutions. g) Find the mean amount of croy- in the original 5.00mL sample w/ corresponding standard deviation in ppb h) what are the confidence intervals at 95% confidence and at 99% confidence? Include all calculations. the difference of the values. Comment on

Part I. Problem solving. Include all necessary calculations 13 provide plots and graphs. Complexation wl diphenyl carbazide (OPC) in acidic media is another type of sensitive photometric method used for the analysis of aqueous. hexavalent chromium. At 540nm the cherry-red complex as a result of DPC reaction w/ chromium can be photometrically measured. at this wavelength. - a 25mL The UV-vis analysis for the determination of nexavalent chromium in ground water sample is given below. The experiment was based on external calibration method w/ each measurement sample prepared are as follows lab sample analysis contained the standard 100 ppb croy cor groundwater sample, volumes used as indicated below), 12.50 mL of 0.02 M H2Soy and 5.50 ml of 100 ppm DPC (wi water to adjust final volume to 25-ml). The main stripping method was square wave voltammetry, following the conditions set in the main ASV experiment. Standard 100 Volumetric Groundwater H2SO4 0.20 M, flask Sample, mL ppb CrO4*, 100 ppm DI H₂O, Absorbance mL DPC, mL mL mL 1 0.00 0.00 12.50 5.50 7.00 0.001 2 0.00 0.00 12.50 5.50 7.00 0.002 3 0.00 0.00 12.50 5.50 7.00 0.004 4 0.00 2.50 12.50 5.50 4.50 0.467 5 0.00 2.50 12.50 5.50 4.50 0.435 6 0.00 2.50 12.50 5.50 4.50 0.397 7 0.00 5.00 12.50 5.50 2.00 0.881 8 0.00 5.00 12.50 5.50 2.00 0.873 9 0.00 5.00 12.50 5.50 2.00 0.821 10 5.00 0.00 12.50 5.50 2.00 0.211 11 5.00 0.00 12.50 5.50 2.00 0.289 12 5.00 0.00 12.50 5.50 2.00 0.199 13 5.00 0.00 12.50 5.50 2.00 0.233 14 5.00 0.00 12.50 5.50 2.00 0.223 a) what is the mean absorbance values for the solutions of: 1) blank 2) 2.50ml Croy standard added 3) 5.00 ml croy 11 11 4) J.00 ml samples added b) Find the least-squares best line through the points of 0.00ml added, 2.50 ml added, 5.00 ml added croy' standards. Find the calibration sensitivity. c) Determine standard deviation of the blank & blank d) what is the LOD nd LOQ of the analysis. what does this values refer to? e) Give the residual plot for the calibration plote, showing each point used in the calibration curve. Determine SCV) f) Determine the standard deviation of groundwater analysis syo based on calibration curve. Show solutions. g) Find the mean amount of croy- in the original 5.00mL sample w/ corresponding standard deviation in ppb h) what are the confidence intervals at 95% confidence and at 99% confidence? Include all calculations. the difference of the values. Comment on

Appl Of Ms Excel In Analytical Chemistry

2nd Edition

ISBN:9781285686691

Author:Crouch

Publisher:Crouch

Chapter12: Spectrochemical Methods

Section: Chapter Questions

Problem 13P

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