Analytical Instrumentation-II (INDSC6A) — DU B.Sc. (Hons) Instrumentation Previous Year Question Papers

1. (a) List three different types of atomization methods in atomic al]sorption (3.) /emission spectroscopy. a) (c) (d) (e) (I) What do you understand by primary and secondary reference electrodes used in electroinalytical `method of analysis. Name any twc} such electrodes. Why does oxygen molecule couldnotbe detectedby R spectroscopy? In IlpLC separation a peak has a retention time of6 min and a width at half height of 0.25 min. Calculate the number of theoretical plates. How is it related to the column efficiency? Disouss the criteria for selecting a carrier gas in GLC. An absoaptionband appears at 1700 cm-1 in an R.spectrum. Calculate: (i) Frequeney of the vibration (ii) Energy of the photon absorbed (Given: C=3xl0L°cm/s) 2. (a) Discuss the radiation sources used in dispersive IR spectroscopy. (6) a) Explain the standard addition method of quantitation used in flane (5+1) emission spectroscopy. How is it different from calibration method? (c) Define boundary potential in a glass electrode. The concentration of (1+5) hydrogen ions in a solution is 2.5 x 10-5 M. Calculate the pll of the solution and comment on whether the solution is acidic or basic. 3. (a) Explain different types of metallic indicator electrodes used in (6) potentiometry. Discuss why the electrodes of first kind are not used frequently? (b) Explain how the equivale.nce point is determined .in potentiometric (4+2) titration. Why are indicators not required in potentiometric titrations? (c) Define the term Resolution in Gas Liquid chromatography. Two peaks (1+4+1) appear at 4.5 min and 5.0 min with peak widths 0.40 min each. Calculate the resolution and comment on the result. (a) `(b) (c) Explain the effect of temperature programming in gas chromatography. Why it is preferr.ed over constant-temperature analysis? Theretentiontimes of two compounds are 5.Omin and 7.0 min. in GLC analysis. The dead time (tin) is 1.0 min. Calculate the selectivity factor. Discuss the principle and working of bulk type and solut.e type detectors (one each) used in IIPLC. (a) Discuss the advantages and limitations ofllpLC over GLC., (5) a) "The C-H stretching appears at around '3000 cng-1 whereas C=O (5) stretching appears at around 1700 cm-I"-explain the reason behind this. (c) Write a detailed note on the Electron capture Detector (ECD) of GLC. List some of its applications. Why is TCD considered a non-destructive detector? (a) (b) (c) Why cannot ordinary glass cells be used in R spectroscopy? What type- of material is used to fabricate the sample cells for R spectroscopy? (5) Calculate the n.umber of vibrational modes for c02 and Hcl molecules, in IR spectroscopy. ` (5) Discuss the different types of nebulizers used in Atomic Absorption (8) (a) List the requirements for using IlpLC pumps. Explain the construction and worki.ng of a Pneumatic pump. (b) What do you understand by the term en`d Capping in IPLC columns. (2+2+2) What is the most commonly used stationary phase in reverse-phase