ANAND INSTITUTE OF HIGHER TECHNOLOGYKAZHIPATTUR

DEPARTMENT OF ELECTRONICS AND INSTRUMENTATION

SUBJECT CODE & NAME: EI2302 & ANALYTICAL INSTRUMENTATION

STAFF NAME: JANSIRANI T.

UNIT 1

COLORIMETRY AND SPECTROPHOTOMETRY

TWO MARKS

1. List the detectors used in UV spectrophotometer (Nov 2006) I. Photovoltaic cell.

II. Photoemission tubes.III. Photomultiplier tube.

2. What is meant by transmittance? (April/ May 2008) The ratio of radiant power transmitted by sample to the radiant power

incident on the sample.

3. What is absorption spectrum? (April 2008) The curve - plotted showing the characteristics of a series of standard against

concentration of the solution.

4. State Beer’s law.For monochromatic radiation, absorbance is directly proportional to the path

length “b” through the medium and concentration “c” of the absorbing species. The relation may be given by, A = abc. Where “a” is the proportionality constant called absorptivity.

5. What is Monochromator?Monochromators are designed for scanning spectrum. Spectral scanning is

necessary or desirable to vary the wavelength of radiation over a considerable range.

6. What are the two types of filters?a. Absorption filterb. Interferance filter.

7. What are the types of wavelength detectors?a. Thermal detectorsb. Photon detectors

8. Give some examples for thermal detectors?a. Thermocoupleb. Thermopilec. Thermistorsd. Pyroelectric detectors

9. What are the techniques used for handling solid samples in IR spectroscopy?a. Solids run in solutionb. Solid filmsc. Pressed pellets.

10. List out some X- ray detectors.a. GM counterb. Proportional counterc. Ionization counterd. Scintilation countere. Solid state counterf. Photon counting.

11. Name the different burners used in Flame photometry.a.Total consumption burners.b. Premix laminar burners.

12. What is pyroelectric transducer?Pyroelectric transducers are insulators with very special thermal and electrical

properties. They are having fast response than that of other thermal detectors. Due to this these detectors are mostly employed in FTIR spectrophotometer.

13. What is the use of Golay cell?It is also called as pneumatic detector. It is used to measure the intensity of

Infrared radiation by the Principle of expansion of gas upon heating.

14. What are the the types of detectors in IR spectroscopy?i. Bolometersii. Thermocouplesiii. Thermistorsiv. Golay cellv. Pyroelectric transducervi. Photo conductivity cell

15. What are the properties of electro magnetic radiation?i. Wave lengthii. Frequencyiii. Velocityiv. Wave numberv. Amplitude

16. State Bouguer’s law. The mathematical statement which states that the radiant power absorbed is proportional to the thickness traversed is called the Lambert’s law given by Ln p0-ln p=ln (p0/p) =k’b.

17. State Lambert-Beer law. The relation representing Lnp0/p=kbc Where p0 is the radiant power at c=0 and p is the radiant power at c=c and c is the concentration of absorbing species.

18. State the process involved in AAS. The AAS phenomenon can be divided into two major processes 1. The production of free atoms from the sample 2. The absorption of radiation from an external source by these atoms.

19. Give the advantages of grating monochromators 1. Gratings can be made with materials like aluminium which are not affected by

moisture. 2. Grating monochromators can be used over wide wavelength ranges

20. Give the advantages and disadvantages of fourier transform IR spectrometers. Adv:

1. FIFR methods are faster than dispersive instruments and hence specially useful in situations that require fast repetitive scanning. 2. FIFR provides increased energy throughput.

Disadv: 1. It is expensive than sequential dispersive instruments 2. For the precise movement of the mirror computer is also needed.

21. What is a Monochromatic?Monochromatros are designed for scanning a spectrum. Spectral scanning is

necessary or desirable to vary the wavelength of radiation over a considerable range.

22. What are the types of longer wavelength detectors?Thermal detectors in which the IR produces a heating effect that alters some

physical property of the detector.

Photon detectors which uses the quantum effects of the IR radiation to change the electrical properties of a semiconductor.

23. Distinguish between fluorescence and phosphorescenceFluorescence-It is a process in which the material emits the lamination whenever

it is illuminated with a source. It stops emission of radiation whenever the source is switched off. But phosphorescence continues its emission after the source is switched off.

24. What are the Limitations of glass electrode? (April/ May 2006)(i)In strongly acidic solutions of pH<1, the salt effect due to anions is observed.

(ii)It can be used upto a pH of 13 but being sensitive to Na+ ions above a pH of 9, the linear relationship between glass electrode altered. So an alkaline error is introduced beyond a pH of 9, which should be taken into consideration.

(iii)It does not function properly in some organic solvents like pure alcohol.

16 MARKS1. With neat sketch, explain the principle, construction and working of FTIR

spectrophotometer. (April 2008)2. With necessary diagram, describe the principle construction and working of U-V

Spectrophotometer. (April 2008)3. Derive Beer’s law and also discuss the reasons for deviation in Beer’s law

(November 2006)4. With neat diagram explain single beam and double beam instruments used in UV

spectrophotometer. (November 2006)5. List the reasons for deviation of Beer’s law in absorption spectrophotometry. (May

2006)6. With neat diagram explain the principle of IR spectrophotometry and also discuss

about the detectors used. (May 2006)7. Explain the Flame emission photometer with its Instrumentation.8. Explain in detail about

i. Photovoltaic cellii. Photo emissive tubesiii. Photo multiplier tube

UNIT II

1. What do you mean by “open tabular column”? (Nov 2006) Like one of the capillary columns used in gas chromatography.

I. These tables are 0.25 mm in diameter length varying between 30 m -300 mII. Cross diffusion with narrow diameter enables high efficiency.

III. This is of 2 types. Wall – coated Support – coated

2. Define Retention time & Retention volume? (Nov 2006), (April 2007) Retention time (TR): The time is take after the sample injection for the analyze peak to reach the detector. Retention Volume (VR): The volume of mobile phase that is required to convey a route band from the point of injection through the volume of detector.

3. Define the term volume dead volume with respect to chromatograph? (Nov 2006)

The dead volume/void volume/dead space [VM or Vo] is the volume of the null phase from the point of injection through the volume of detectors

4. Discuss the main factors which influence the efficiency of a chromatographic column. (May 2006)

I. Plate HeightII. Plate number / Plate Count.

5. Define column chromatography? (April 2008) In column chromatography the stationary phase is held in a narrow tube

through which the null phase is under pressure.

6. Name any four detectors used in liquid chromatography? (April 2006), (April/ May 2008)

I. UV- missile spectro photometric detector.II. Fluorescence detectors.

III. Refractive induce detectors.IV. Electrochemical detectors.

7. What is chromatography?It is a physical or chemical methods of separation in which two mutually immiscible phases are brought in to contact; One is stationary and other is mobile.

8. What are the different chromatographic techniques?a. Gas chromatography

i) Gas – liquid ii) Gas – solid.b. Liquid chromatography

i) Liquid- Liquid ii) Liquid – solid.9. List the experimental procedure on chromatography.

a. Preparation of the stationary phase.b. Introduction of the sample.c. Passing over the stationary phase.d. Collecting the individual components for quantitative or qualitative

purpose.

10. What is the use of Chromatography?The positions of the peak in the time axis are used to identify the

components of the sample (quality), the areas under the peaks provide a quantitative measure of the amount of each component.

11. Chromatography, a short note.Chromatography is defined as the physical and chemical method of

separation between various components of a mixture into pure fractions or bands of each component.

12. Define retention time The time required for each of the components to emerge from sample or

mixture is called as the retention time.

13. Name the different parts of gas chromatography? Sample injection system Chromatographic columnThermostat Detector Recorder.

14. Explain chromatographic column. The column acts as the heart of a gas chromatography, where the fundamental process of separation takes place. Its action is based on the fact that when a sample of gas or vapour is introduced into the column, it spreads by molecular diffusion to give a concentration profile. As the sample moves through the column, additional spreading takes place. But, the band maintains the general shape, which is detected and recorded as a chromatographic peak.

15. What is pyrolysis? Pyrolysis is an accepted method of handling solid samples. It extends gas chromatographic analysis to compounds such as rubber, soil, textiles, coals, resins, polymers, paint films etc. The method lends itself to studies on heat stability and thermal decomposition. It is also called as controlled thermal fragmentation.

16. Mention the applications for smoke meter.(April 2007) Due to variable sampling volume a detection limit of 0.002FSN (~20 μ g/m³)

can be reached Can be used for engine testbed and chassis dynamometer Timely paper change due to remaining filter paper indicator Altitude measurements and simulation up to a sea level of 5000 m High reproducibility, improved cleaning efficiency and increased robustness

against wet exhaust gas due to shop air purging of the entire gas path – option Extended application area up to 3bars exhaust back pressure for engines with

exhaust aftertreatment systems - option Remote-control service with intuitive user interface – option

 

16 MARKS

1. With neat line diagram explain the various stages of gas chromatography. (November 2006)

2. Explain any two types of detectors used in liquid chromatography. (November 2006)

3. Explain the principle of Gas chromatography and the functions of various units in the instrument. (May 2006)

4. Explain the principle of any two detectors used in liquid chromatography. (May 2006)

UNIT III

1. State the principle of any one type of dust monitor. (Nov 2006) The optical type duct monitor measure the amount of dust present in a moving gas by plating a clean glass plate in its path lae sometime later analyze the deposition of dust on it.

2. Define thermal conductivity. (May 2006), (April/ May 2008)The thermal conductivity is one of the principle methods in one analysis of

the temperature of fine gases like O2, N2, Co etc in its gas mixture.

3. Name any two methods to estimate No2 in air? (April 2008)

1. Industrial Emission Monitoring.

Non dispersive UV & IR method.

Chemilumeneseent method.

Gas Chromatographic method.

Electrochemical method.

2. Ancient air analysis.

Colometric Method

Coulometric method

4. What is the use of chemiluminescence method?Chemiluminescence method is used for determining components of gases

originated with the need for highly sensitive means for determining atmospheric pollutants such as ozone, oxides of nitrogen and sulphur compounds.

5. How can we Measure nitrogen from auto mobile?The nitrogen content of automobile gas has been determined by Thermal

decomposition of the gas at higher temperature in a steel tube.

6. What is a cell?It is a single arrangement of two electrodes and an electrolytic solution

with in the cell, capable of producing chemical action due to passage of electricity through the cell.

7. What are the two functions of electrochemical cells?a. To convert chemical energy in to electrical energy.b. To convert electrical energy in to chemical energy.

8. What are the properties of standard cell?a. Well known reproducible potential constant with time.b. Reversibility of the cell.c. Low temperature co-efficient of e.m.f.d. No permanent damage on passing an electric current.

9. What are the basic components of analytical instruments?a. A stable source for radiant energy.b. A transparent container for holding the sample.c. Spectral scanning device.d. Radiant detector.e. Signal processing and read out.

10. What are the components of potentiometric methods?a. Reference electrode.b. Indicator electrodec. Potential measuring device.

11. Give the working principle of electrical conductivity meter? The instrument works on the following principle, that the conductivity of an aqueous solution depend on the inorganic impurity,& the instrument measures this in terms of resistance of a std: water column or tube through which the sample is passed. the conductivity is the reciprocal of resistance.

12. Give the methods of measurements of Oxygen? Methods used to measure Oxygen are classified as either Physical or Chemical

methods. Physical method uses the paramagnetic property of Oxygen or thermal conductivity as the basis for quantitative determination. Chemical method includes potentiometric & catalytic combustion.

13. Give the application of Silica analyzer?In thermal power plants, silica content is measured in steam before turbine. Silica

analyzers are used for anion exchanger, effluent monitoring & effluents of mixed –bed exchangers.

14. what is chemical blank measurement? In this sequence the ammonia molybdate solution, sulphuric acid & reduction

solution are simultaneously added to the mixing vessel. This solution is diluted with sample to a suitable volume & is then emptied to the, measuring curvette where it is measured & drained away. This is known as chemical blank measurement.

15. what is the use of blank in silica analyzer? The reason for the use of blank on each cycle is to give the analyzer long term

stability by compensating for the effect of variables such as coloration of the sample or reagents, temperature, or aging of the lamp of photo cell.

16. Give the application of Sodium analyzer?Sodium analyzers find applications in thermal power plants for determining

sodium ion concentration in boiler water, monitoring carry over detection of condenser leaks &the exhaustion of water treatment plant cat ion exchange units.

17. Explain the different analysis methods of Nitrogen Oxide? (April/ May 2008) i) Infrared ii) Ultraviolet iii) Chemiluminescent iv) Colorimetric v) Electrochemical

16 MARKS

1. With neat diagram, describe the construction and working principle of paramagnetic oxygen analyzer. (April 2008)

2. Device a method to estimate the amount of hydrocarbons present in air with neat instrumentation setup. (April 2008)

3. With necessary diagram, explain the working of dust meter. (April 2008)4. With neat line diagram explain any two types of industrial analyzers. (November

2006)5. Explain any one type of oxygen analyzer used in industrial application. (May 2006)

6. With neat diagram explain in detail about gas analyzers.

UNIT IV

1. Discuss the disadvantage of glass electrode? (Nov 2006) Gives accurate results to only low pH values. Slower response. Can be matched only with distilled water. Not fit fee highly acidic solution etc

2. List the methods used for measuring oxygen in flue gas. (May 2006)1. Paramagnetic oxygen analysis [physical]2. Electro analytical method [chemical]

3. What is meant by Bio-sensor? (April 2008) A Bio sensor is a device that uses biological materials to monitor the

presence of various chemicals in a substance.

4. Define pH value of solution. (April 2008), (April 2007) The number of gram ions of hydrogen present in 1L of the solution is

called hydrogen ion concentration.pH = - log10 [H+]

5. What are the properties of reference electrode?a. Irreversible and obeys the Nernst equation.b. Exhibits a potential that is constant with time.c. Returns to its original potential after being subjected to small

currents.

6. Write a note on calomel electrode.Calomel reference electrodes consist of mercury in contact with a

solution that is saturated with mercury (I) chloride and that also contains a known concentration of potassium chloride. It has large temperature co-efficient.

7. Give some examples for ion selective electrodes.a. Gas membrane typeb. Solid & liquid matrix electrodes.c. Gas sensing electrodes.d. Biocatalytic membrane electrode.

8. What are the properties of ion selective electrode?a.Minimal solubilityb. Electrical conductivityc.Selective reactivity with analyte.

9. What is the principle of H2S analyzer? Sample at a constant flow rate enters a humidifier where it bubbles through a 5% acetic acid solution. The sample then flows into the reaction window of the sample chamber, where it passes over an exposed surface of paper sensing tape impregnated with lead acetate. H2S reacts with lead acetate to form lead sulfide causing a brown stain on the paper. The rate of reaction and resulting rate of color change is proportional to the concentration of H2S in the sample.

10. What is the use of protective filter in Industrial analyzer? In Industrial analyzer gas- handling components should always include a small protective filter, preceded by a major filter if the gas contains suspended matter that requires removal.

11. What is the use of stream drying equipment? If a gas sample has a water vapour concentration high enough to cause condensation within the analyzer, or if moisture is an interferent, stream drying equipment is necessary.

12. What is the need of bypass pumping devices? The bypass pumping devices are needed to keep fresh sample rapidly supplied to the input of the analyzer.

15. What are the applications of oxygen analyzer? i) It is used in the areas of oxygen absorption studies on plants and tissues.ii) It is used in food processing industries.iii) It is also used in respiratory studies.

16. Define reduction.Reducton is defined as the process which involves gain of electrodes by a

substance.

17. Define electrode.Electrode is a material or a metallic rod or bar or strip through which electrons

flow. There are two types of electrodes. They are1. Anode2. Cathode

18. Define electrolyte.Substance who’s metal or aqueous solution conduct the electric current and which

are decomposed by the passage of electric current are called electrolytes.

19. Define pH value of solution.(April/ May 2008)pH is a measure of the acidity or basicity of an aqueous solution.[1] Pure

water is said to be neutral, with a pH close to 7.0 at 25 °C (77 °F). Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline.

20. What is meant by bio – sensor? (April/ May 2008)

A biosensor is an analytical device for the detection of an analyte that combines a biological component with a physicochemical detector component.

It consists of 3 parts:

the sensitive biological element (biological material (e.g. tissue, microorganisms, organelles, cell receptors, enzymes, antibodies, nucleic acids, etc.), a biologically derived material or biomimic) The sensitive elements can be created by biological engineering.

the transducer or the detector element (works in a physicochemical way; optical, piezoelectric, electrochemical, etc.) that transforms the signal resulting from the interaction of the analyte with the biological element into another signal (i.e., transducers) that can be more easily measured and quantified;

Associated electronics or signal processors that are primarily responsible for the display of the results in a user-friendly way.[1] This sometimes accounts for the most expensive part of the sensor device, however it is possible to generate a user friendly display that includes transducer and sensitive element(see Holographic Sensor)

16MARKS

1. With a schematic diagram, explain the working principle of dissolved oxygen analyzer. (April 2008)

2. Explain the working principle of sodium analyzer with neat diagram. (April 2008)

3. Explain how pH is measured using glass electrode with suitable diagram. (April 2008)

4. With neat sketch explain the principle and operation of calomel electrode. (November 2006)

5. With a neat sketch explain the temperature compensation used in pH measurement (November 2006)

6. Explain with neat diagram the construction and working of silica analyser. (May 2006)

7. Explain the function of Hay’s magnetostrictive analyzer used for measurement of oxygen in steam of gas. (May 2006)

8. Explain the construction and working principle of solid membrane electrode. (May 2006)

9. With suitable example. (May 2006)(i) Explain thermogravimetric analysis.(ii) Differential thermal analysis.

UNIT V

1. List the advantage of thermal conductivity detector. (Nov 2006).I. Non destructive

II. Subjects to thermal effects.

2. List the detectors used in UV spectrophotometer. (Nov 2006).I. Fluorescence Detector

II. Refractive index DetectorIII. Adsorption DetectorIV. Electrical conductivity Detector V. Thermal Detector

VI. Mass Detector

3. List the advantages of mass spectrometer. (Nov 2006)I. High sensitivity

II. Low molecular weightsIII. Capability of handling gas mixtures.

4. List the application of NMR spectrometer. (May 2006)I. Uses radio frequency radiation to induce transitions between different

nuclear Sp in states of samples in Magnetic field.II. They used for quantitative measurements, but is most use full for

determining the structure of molecules along with IR spectroscopy and mass spectrometry.

5. What is GM counter? (May 2006)It is Geiger-Muller counter. Commonly called GM tube the Gas is

ionized in the counting, Migration of ions takes place towards appropriate electrodes under the voltage gradient. This will be rewarded in the GM Counter.

6. What is NMR?It is the study of absorption of radio frequency radiation, by nuclei in a

magnetic field. The expansion of this term is nuclear magnetic resonance. It is a kind of spectrometer.

7. Different types of mass spectrometer?a.Magnetic sector analyzer spectrometersb. Double focusing spectrometersc. Time of flight analyzers spectrometersd. Quadrupole mass spectrometer

8. What is gamma camera.It is an imaging device, most commonly used as a medical imaging device in nuclear medicine.it is a complex device also it consist of an acquisition system for operating the camera for storing the images.

9. List the types of mass analyzer?a. Magnetic sector analyzersb. Double focusing spectrometers.c. Time of flight analyzers.d. Quadrupole mass spectrometers

10. List the applications mass spectrometers.a. All the metals can be recognized by the mass spectrometry.b. Molecular mass can be accurately determinedc. The isotopic abundance of easily vaporizable elements can be determined.

11. What is the basic principle of NMR? Elementary particles such as electrons or nucleus behave as if rotates about an axis and thus have the property of spin. The angular momentum associated with the spin of particle will be an integral or a half integral multiple of h /211, where is h is Planck’s constant

12. What are the basic components of NMR Spectrometry? (April/May 2008) The basic components of the NMR spectrometry are:

A Magnet produces magnetic field in the range 10,000 to 25,000 gauss Radio frequency transmitting system. The signal amplifier and detector. A display device, which may be a recorder or an oscilloscope.A non-magnetic sample holder, which holds this sample.

13. What is Mass Spectrometry? Mass spectrometry is the most commonly used method which provides

qualitative and quantities information about the atomic and molecular composition of organic and inorganic materials. It produces charged particles that consist of the parent ion and ionic fragments of the original molecule, and it sorts these ions according to their mass/charge ratio.

14. What is the principle behind the GM counter? When an ionizing particle enters the counter, collision with the filling gas produces ion pairs. The formed ion pairs move towards the appropriate electrode under the voltage gradient. The mobility of electron is high and under this potential gradient it acquires sufficient velocity to produce new ion pairs by collision with atoms of argon. Repeating of this process produces an avalanche of electron moving towards anode. Electrons when striking generates ionization throughout the tube, called discharge. Each discharge builds a constant pulse counted by scale counter.

15. What is proportional counter? When the electric field at the centre electrode of an ionization chamber is increased above the saturation level, but under that of the Geiger region, the size of the output pulse from the chamber starts to increase but remains proportional to the initial ionization. A device operated in this principle is called a proportional counter.

16. Mention the limitations of NMR 1. Lack of Sensitivity.

2. While character sings the organic compounds, no information about the molecular weight is given, but the relative numbers of different protons present are only known. 3. In some compounds, two different types of H2 atoms at similar resonance frequencies resulting in an overlap of spectra .This makes difficult interpretation of such overlapped spectra. 4. In most of the cases, only liquids can be studied by NMR spectrometry

17. What is the basic instrumentation of X-ray Spectrometer? 1. X-ray generating equipment 2. Collimator 3. Monochromator 4. Detector

16 MARKS1. Explain the construction and working principle of NMR spectrometer with neat diagram. (May 2006)

2. With neat sketch, explain th following detectors .(November 2006)GM counter, (ii) Proportional counter

3 With neat diagram explain single beam and double beam instruments used in UV spectrophotometer. (May 2006)4.Explain the construction and working principle of solid membrane electrode.5.Explain any one type of oxygen analyser used in industrial application.6.With suitable example.

(iii) Explain thermogravimetric analysis.(iv) Differential thermal analysis.

7. Explain the principle of Gas chromatography and the functions of various units in the instrument.

8. Explain the principle of any two detectors used in liquid chromatography.9.List the reasons for deviation of Beer’s law in absorption spectrophotometry.10. With neat diagram explain the principle of IR spectrophotometry and also

discuss about the detectors used.