Chemistry 321L – 02MPost-LabExperiment 4: Measuring the Concentration of Sodium and Potassium in Natural Matrices Using ICP-OESBy: Cameron Kahn12 February 2014TA: Muditha Dias1) flow chart1) Blank Output8ppm calibration was prepared by diluting .2mL ofK+ and Na+ stock solution to 25mL1000ppm solution.4ppm calibration was prepared by diluting .01mL of K+ and Na+ stock solution to 25mL4ppm calibration was prepared by diluting .1mL of K+ and Na+ stock solution to 25mL2ppm calibration was prepared by diluting .05mL of K+ and Na+ stock solution to 25mL.8ppm calibration was prepared by diluting .02mL of K+ and Na+ stock solution to25mLOcean Spray792 ppm of 190mg K in .24mLof Ocean Spray is diluted 100 fold to 7.92ppm62.5 ppm of 15mg Na in .24mL of Ocean Spray is diluted 100 fold to .625ppm83.33 ppm of 20mg K in .24mLof V8 Splash is diluted 100 foldto .833ppmV8 Splash62.5 ppm of 15mg Na in .24mL of V8 Splash is diluted 100 fold to .625ppm****All eight of the solutions are then injected into the ICP-OES.A blank is prepared by the same dilution factors as the other two samples.BlankK_4044 K_7664 Na_5889 Na_58958602 1630 2316 1512The blank appears to contain detectable sodium and potassium because the output was positive for both potassium and sodium in each of the samples.3) Calibration curve0 1 2 3 4 5 6 7 8 9020004000600080001000012000140001600018000f(x) = 1854.91x + 1049.88R² = 1f(x) = 1529.86x + 1959.03R² = 1f(x) = 500.07x + 1473.19R² = 1f(x) = − 70.39x + 7978.79R² = 0.84Calibration curveK_4044Linear (K_4044)K_7664Linear (K_7664)Na_5889Linear (Na_5889)Na_5895Linear (Na_5895)Concentration (ppm)Counts per second4) Standard error of regression equations Regression Equation Standard Error (Calculated in Excel)K_4044 ± 109.60K_7664 ± 83.64Na_5889 ± 305.94Na_5895 ± 393.515)analyte V8 countsBackground level average background levelK_4044 8394 -5.9 -0.723±.137ppmK_7664 2261 1.58Na_5889 3117 0.76Na_5895 2294 0.67analyteO.S. countsBackground level average background levelK_4044 8239 -3.7 5.61±.295ppmK_7664 9060 15.17Na_5889 11050 5.94Na_5895 10360 5.026)Ocean Spray V8Calculated ppm 5.61ppm -.723ppmNa K 02468Concentrations of AnalytesOcean SprayV8AnalytesConcentration ppm7) Concentration of analytes with background subtractedK 4044 K 7664 Na 5889 Na 589500.511.52Concentration of Analytes with Backgrounds SubtractedOcean SprayV8AnalytesConcentration ppm8) a. We used Microsoft excel to find the t-value which was calculated to be 3.779 which is larger than the t-table value of 3.182 at 95% confidence interval for 3 degrees of freedom; therefore concluding that our hypothesis is correct. b. we used Microsoft excel to find the t-value to be .19568 which is smaller than the t-table valueof 3.182 which causes us to reject the hypothesis that the samples are different and accept that they are the same9) Based on our findings at the 95% confidence interval, there is no statistical difference betweenthe sample and the
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