Analytical Chem istry - DePauw University

652 Analytical Chemistry 2.0P total (torr) absorbance595 0.1146354 0.0642332 0.0591233 0.0412143 0.0254Determine the %CO for each sample, and report the mean value andthe 95% confidence interval.23. Figure 10.32 shows an example of a disposable IR sample card madeusing a thin sheet of polyethylene. To prepare an analyte for analysis, itis dissolved in a suitable solvent and a portion of the sample placed onthe IR card. After the solvent evaporates, leaving the analyte behind asa thin film, the sample’s IR spectrum is obtained. Because the thicknessof the polyethylene film is not uniform, the primary application of IRcards is for a qualitative analysis. Zhao and Malinowski reported howan internal standardization with KSCN can be used for a quantitativeIR analysis of polystyrene. 26 Polystyrene was monitored at 1494 cm –1and KSCN at 2064 cm –1 . Standard solutions were prepared by placingweighed portions of polystyrene in a 10‐mL volumetric flask anddiluting to volume with a solution of 10 g/L KSCN in methyl isobutylketone. A typical set of results is shown here.g polystyrene 0.1609 0.3290 0.4842 0.6402 0.8006A 1494 0.0452 0.1138 0.1820 0.3275 0.3195A 2064 0.1948 0.2274 0.2525 0.3580 0.2703When a 0.8006-g sample of a poly(styrene/maleic anhydride) copolymerwas analyzed, the following results were obtained.replicate A 1494 A 20641 0.2729 0.35822 0.2074 0.28203 0.2785 0.3642What is the %w/w polystyrene in the copolymer? Given that the reported%w/w polystyrene is 67%, is there any evidence for a determinateerror at a = 0.05?24. The following table lists molar absorptivities for the Arsenazo complexesof copper and barium. 27 Suggest appropriate wavelengths for analyzingmixtures of copper and barium using their Arsenzao complexes.26 Zhao, Z.; Malinowski, E. R. Spectroscopy 1996, 11(7), 44–49.27 Grossman, O.; Turanov, A. N. Anal. Chim. Acta 1992, 257, 195–202.