instru

sample has to be

1- volatile ( non volatile are converted to volatile using sylation - reaction of trimethylsilyl with active hydrogen atom in analyte- carboxylic acid,alcohol 2- organic or inorganic ( inorganic analyzed via : formation of stable volatile metal chelates with TFA , HFA)

7- Which of the following statements is correct? A. Infrared radiation has a shorter wavelength than visible light. B. Ultraviolet radiation has a longer wavelength than infrared radiation. C. Infrared radiation has a lower wavenumber than visible light. D. Microwave radiation possesses more energy than infrared radiation.

C. Infrared radiation has a lower wavenumber than visible light.

isosbestic point

A wavelength at which the absorbance spectra of two species cross each other. The appearance of isosbestic points in a solution in which a chemical reaction is occurring is evidence that there are only two components present, with a constant total concentration.

In which type of chromatography, the stationary phase held in a narrow tube and the mobile phase is forced through it under pressure? A. Column chromatography B. Planar chromatography C. Liquid chromatography D. Gas chromatography

A. Column chromatography column - 3D (tube) planar - 2D (paper)

In chromatography, the stationary phase can be ___________ supported on a solid. A. Solid or liquid B. Liquid or gas C. Solid only D. Liquid only

A. Solid or liquid

1-How should the concentration of a colorless sample be determined? A. Using a UV spectrophotometer B. Using a VIS spectrophotometer C. Either a UV or VIS spectrophotometer D. Using an indicator solution and pH paper

A. Using a UV spectrophotometer

In GC, The sample port is ـــــــــــــــــــــــــــــ the boiling point of the lowest one of the analytes. a) 50 °C above b) equal to c) below d) 100 °C above

a) 50 °C above

In ion exchange chromatography, the nature of function group of the resin is a) Anionic or cationic. b) Anionic and cationic. c) Anionic. d) Cationic.

a) Anionic or cationic.

In GC separation of a complex volatile mixture, the analyst needs to: a) Choose a column with liquid stationary phase of similar polarity to the sample components b) Use a packed column c) Use the highest possible mobile phase velocity. d) Use the highest possible column temperature e) All of the above

a) Choose a column with liquid stationary phase of similar polarity to the sample components

In chromatogram, the position of peaks on the time axis can be used to determine which of the following? a) Components of the sample b) Amount of component in the sample c) Column efficiency d) Column resolution

a) Components of the sample

The time required for a molecule of the mobile phase to pass through the column is called ___________ a) Dead time b) Solute migration rate c) Adjusted retention time d) Retention time

a) Dead time

Theoretical plates are used to. a) Estimate the efficiency of the column b) Determine the thickness of stationary phase c) Measure the distribution of analyte between stationary phase and mobile phase d) Measure the migration rate

a) Estimate the efficiency of the column

Which of the following is a special adsorbent used in gas-solid chromatography? a) Molecular sieves b) Silica gel c) Alumina d) Starch

a) Molecular sieves

Which of the following columns can be used in Gas-solid chromatography? a) Open tubular column b) Analytical column c) Separation column d) Guard column

a) Open tubular column

- Calibration curve in Chromatography is a plot of: a) Peak area versus concentration. b) Absorbance versus Concentration c) Detector response versus Time d) Emission intensity versus concentration

a) Peak area versus concentration.

Which of the following conditions will cause the efficiency of the column to increase? a) Plate number becomes greater, plate height becomes smaller b) Plate number becomes smaller, plate height becomes smaller c) Plate number becomes smaller, plate height becomes larger d) Plate number becomes greater, plate height becomes larger

a) Plate number becomes greater, plate height becomes smaller

In Column chromatography, the stationary phase is made of _________ and the mobile phase is made of _________ a) Solid, liquid b) Liquid, liquid c) Liquid, gas d) Solid, gas

a) Solid, liquid

The mechanism of separation in molecular size chromatography depend on a) molecular size and shape b) partition c) charge and size d) ion pair interaction

a) molecular size and shape

which of the following transitions is mostly responsible for UV-visible light absorption in phenyl ring: a) pi->pi* b)n->n* c)n->pi* d) non of the above

a) pi->pi* since phenyl has double bond

in ion exchange chromatography , the strong anion exchange resin contains ................. functional group : a) quantry ammonium b) tertiary amine c) sulphonic acid d) carboxylic acid

a) quantry ammonium

- -..................are unsaturated groups in the molecule that are essential for UV-Visible light absorption. a- Chromophores b- Auxochromes c- Electron withdrawing groups e.g ̶NH2 d- Single bonds

a- Chromophores

peak area

area enclosed by the peak and peak base ( peak hight x peak width at half of peak height)

atomic spectroscopy and molecular spectroscopy

atomic : light source --> hallow cathode lamp sharp lines more selective less interference since lines molecular : Detureum --> UV , tungesten : visible bands less selective more interference

atomic fluorescence

atoms are excited by external lamp or laser absorption of radiation

In GC, The length of capillary column is a) 2-50 m b) 10-100 m c) 2-8 m d) 30-50 m

b) 10-100 m

Gas-solid chromatography is based on which of the following processes? a) Partition of the analyte between a gaseous mobile phase and a stationary liquid phase b) Adsorption of gaseous substances on solid surface c) Ion exchange d) Large molecules cannot penetrate through the gel

b) Adsorption of gaseous substances on solid surface

In chromatogram, the area under the peak can be used to determine which of the following? a) Components of the sample b) Amount of component in the sample c) Column efficiency d) Column resolution

b) Amount of component in the sample

What happens during the 'elution from the column' stage in chromatography? a) Components with greatest affinity elute first b) Components with least affinity elute first c) Components elute in a random manner d) Components elute according to their concentration in the mixture

b) Components with least affinity elute first affinity : تقارب

Which one of the following methods is the most suitable for amino-acid analysis? a) Gas chromatography b) Ion exchange chromatography c) Paper electrophoresis d) size exclusion chromatography

b) Ion exchange chromatography

In chromatography, which of the following can the mobile phase be made of? a) Solid or liquid b) Liquid or gas c) Gas only d) Liquid only

b) Liquid or gas

In molecular size chromatography, the polymeric material used made from a) Starch b) Polysaccharide c) Silica d) Alumina

b) Polysaccharide

Which of the following is the volume of mobile phase required to make a solute peak move from the point of injection through the column to the detector? a) Dead volume b) Retention volume c) Void volume d) Adjusted retention volume

b) Retention volume

Which of the following steps takes place after application of sample in Column chromatography? a) Detection of components b) Separation in the column c) Elution from the column d) Collection of eluted component

b) Separation in the column

Resolution is proportional to. a) Number of theoretical plates of the column b) Square root of number of theoretical plates of the column c) Square of number of theoretical plates of the column d) Cube root of number of theoretical plates of the column

b) Square root of number of theoretical plates of the column

In gas chromatography, the analyte is loaded onto the column via a heated injection port, where it a) condenses b) evaporates c) cooled d) heated

b) evaporates

In ion exchange chromatography, the solvent used is a) organic solvent. b) water. c) buffer solution. d) diluted acids.

b) water.

- Partition coefficient is defined as

b)Concentration of solute in liquid stationary phase/Concentration of solute in liquid mobile phase

In adsorption chromatography, the most adsorbed compound of the following is: a- Carbonyl b- Acid c- Ester d- Hydrocarbon

b- Acid

- In liquid-solid chromatography, the mechanism of separation is: a- Partition b- Adsorption c- Size exclusion d- Sieving

b- Adsorption

29- Gas-solid chromatography is based on which of the following processes? a. Partition of the analyte between a gaseous mobile phase and a liquid stationary phase. b- Adsorption of gaseous substances on solid surface. c- Ion exchange process .d- Large molecules cannot penetrate the gel

b- Adsorption of gaseous substances on solid surface.

-..................are saturated groups in the molecule which possess unshared electrons and causes red shift. a- Chromophores b- Auxochromes c- Chromogens d- Conjugated double bond

b- Auxochromes sarurated : auxochromes unstanration : chromes red shift - batho blue shift- hyps

- Chromatographic methods can be classified according to the technique used into: a- Adsorption and partition chromatography b- Column and planar chromatography c- Gas and liquid chromatography d- Affinity and gel chromatography

b- Column and planar chromatography

Continuous variation method (Job's method) is used for: a- Determination of maximum wavelength b- Determination of the reaction stoichiometry c- Determination of isosbestic point d- Determination of unknown concentration

b- Determination of the reaction stoichiometry

- Which one of the following methods is the most suitable for amino-acid analysis? a- Gas chromatography b- Ion exchange chromatography c- Paper electrophoresis d- Size exclusion chromatography

b- Ion exchange chromatography

Which one of the following methods is the most suitable for amino-acid analysis? a-Gas chromatography b- Ion exchange chromatography c- Paper electrophoresis d- Size exclusion chromatography

b- Ion exchange chromatography

Which statement is true about partition chromatography? a- Separation is based on the relative difference in ionic charge of components to be separated. b- It involves the use of gas or liquid mobile phase. c- The stationary phase is a finely divided solid. d-The component with lower solubility in the stationary phase travels more slowly than that of higher solubility.

b- It involves the use of gas or liquid mobile phase.

Excited atoms in vapor state can emit: a- Continuum spectra b- Line spectra c- Band spectra d- All of the above e- None of the above

b- Line spectra

The GC chart obtained the experiment is called a) Chromatograph b) Chromophore c) Chromatogram d) Graph

c) Chromatogram

Adjusted retention time is the remaining retention time after subtracting __________ from ___________ a) Solute migration rate and retention time b) Retention time and solute migration rate c) Dead time and retention time d) Retention time and dead time

c) Dead time and retention time

In molecular size chromatography, the molecules leave the column in order of a) Increasing size b) Increasing charge c) Decreasing size d) Decreasing charge

c) Decreasing size - the higher size leave the column first

Which of the following is the commonly used support material for the packed column in gas chromatography? a) Glass b) Metal c) Diatomaceous earth d) Stainless steel

c) Diatomaceous earth

What must be the value of the selectivity factor? a) Equal to 1 b) Less than 1 c) Greater than 1 d) Greater than 0

c) Greater than 1

To determine Fe in a blood sample by AAS, you will need the following: a) Special radiation source for blood b) Open tubular column c) Iron hollow cathode lamp d) Helium gas e) Colored iron complex e.g., Fe(SCN)2+

c) Iron hollow cathode lamp

In Gas-liquid phase chromatography, the stationary phase is composed of _________ and the mobile phase is made of _________ a) Solid, liquid b) Liquid, liquid c) Liquid, gas d) Solid, gas

c) Liquid, gas naming : mobile-stationary

The selectivity factor is used to describe. a) Estimate the efficiency of the column b) The proportional difference between chromatographic peaks c) The relative separation achieved between two species d) Measure the migration rate in the column

c) The relative separation achieved between two species

When the analyte is lack of chromophore, the best technique to analyse it a) paper chromatography b) column chromatography c) gas chromatography d) HPLC

c) gas chromatography

7- An acceptable value for the retention (capacity) factor (k'): a) 0.01 b) 0.2 c)3.0 d) 40.0

c)3.0

The following is unit less: a) Asymmetric factor b) Fluorescence quantum yield c) Absorbance d) Capacity factor e) Transmittance (T) f) All of the above

f) All of the above

elution process : Isocratic elution

fixed solvent composition - longer separation time - mixture of 8 aromatic compounds - good resolution

The analytical signal in Atomic Absorption Spectrometry f) Current intensity g) Absorbance h) Mobile phase velocity i) Solvent polarity

g) Absorbance

The mobile phase in chromatographic technique should be:

gas/liquid

resonance fluorescence

generates most intense fluorescence , lamda emitted=lamda absorbed radation

assymetry factor (As)

good column when its 0.9-1.2 As=b/a

electrothermal atomizer

graphite tubes that are heated by passing on electrical current through it no nebuilzer step ( sample as drop spray or solid)

The following term is relevant to HPLC: f) Open tubular columns g) Temperature program h) Normal phase i) Graphite furnace j) Melting endotherm

h) Normal phase

HPLC advantages

high speed and resolution and can have automation and error<1%

number of theoretical plates (NTP)

index used to determine the efficiency of columns (higher NTP , higher efficiency) NTP = 16(tr/w)^2

size exclusion chromatography

known as : gel permeation , filtration chromatography , molecular sieve chromatography seperation : based on (molecular size and shape) large molecules ( too large for the pores) - elute first small molecules (elute last) elution rates : depend of relative sizes column packing : polymers ( polysaccharide, dextrans , epochloryin)

Atomic emission

laser - because of high thermal energy of flame thermal excitation

atomic absorption

light source : hallow cathode lamp (atmos absorb some of light and rest reaches detector) optical excitation

Hallow Cathode Lamp

light source for atomic absorption consists : tungsten anode , hallow cylindrical cathode sealed in glass tube filled with inert gas (neon or argon under reduced pressure) each element has its own unique lamp

- In liquid-liquid chromatography, the stationary phase is

liquid

peak width

magnitude of the peak base intercepted by the tangents to the infliction points of the peak

resolution (rs)

separation of two peaks with different retention rs = 2(trb - tra) / wa+wb general eq: root n / 4 (alpha-1/alpha)(kb/1+kb) so its proportional to root of number of theoretical plates

selectivity factor - separation factor (alpha)

separation of two peaks; alpa = k'b/k'a

The provided absorption spectrum (Wavelength 400-800 ) could be for the following molecular species; Hemoglobin Chlorophyll Acetone Methylene blue Potassium permanganate

since its UV : only Acetone is not colored

In gas-solid chromatography, the stationary phase is:

solid

In liquid-solid chromatography, the stationary phase is:

solid

atomic spectroscopy

the study of the electromagnetic radiation absorbed and emitted by atoms

retention time (tr)

time between sample injection and appearance of solute peak

dead time (tm or to)

time it takes for an unretained species (mobile phase) to pass through a column

in gas chromatography ; separation occurs according to

time spent in stationary phase

adjusted retention time (t'r)

times solute spent in stationary phase ( t'r = tr-to)

Job's Plot

used to determine the stoichiometry of the reaction

elution process : gradient elution

variable solvent composition - shorter separation time - good resolution

in gas chromatography sample and mobile phase are:

volatile (gas)

Gas chromatography (GC) is a successful analytical technique for qualitative and quantitative analysis. The following is correct for GC: a) Suitable for direct analysis of gases and other volatile samples b) The qualitative analysis is possible from the retention time of each component c) The quantitative analysis is possible from the peak height or peak area d) The separation is achieved by different retention of sample components in the column e) All of the above

e) All of the above

GC capillary column (open turbular)

(A) well coated open tubular (wcot) - made of : glass , stainless steel , fused silica - FSOT - more thinner more flexible , less reactive , good physical strength(most used) - length (10-100m) pressure (low) flow rate (low) sample loading capacity (low) sufficient, good resolution short analysis time (B)support coated open tubular (scot) larger in diameter less efficient than wcot larger sample loading capacity than wcot (c) porous coated open tubular - pcot

4. An important advantage of a double-beam spectrophotometer over a single-beam spectrophotometer is that (a) it permits cancellation of slow variations of the source power (b) it requires same light source for Uv, Vis, and Infra red radiation (c) it can be used in conjunction with rapid response detection systems (d) a greater range of wavelengths can be used.

(a) it permits cancellation of slow variations of the source power

2. What are the dimensions of the molar absorptivity in the Beer's law expression ? (a) Moles per liter (b) Liters per mol. centimeter (c) Grams per mole (d) Micrograms per square centimeter

(b) Liters per mol. centimeter

Grating is a device used in the spectrophotometer to function as (a) a light source (b) a monochromator (c) a detector (d) a nebulizer

(b) a monochromator

3. The region of the electromagnetic spectrum in which the highest energy photons are observed is the (a) ultraviolet (b) infrared (c) microwave (d) x-ray

(d) x-ray

atomic absorption spectrometer components

1- atom cell - atomizer ( flame or electrothermal - graphite furnace) 2- light source ( hallow cathode lamp) 3- monochromator 4- detector and read out device

smaller particle size leads to :

- higher NTP - lower HETP - higher pressure - shorter optimum run time

GC packed column

- made of : glass, stainless steel , teflon(most common) length (2-20m) pressure (high) flow rate (high) sample loading capacity (high) insufficient, poor resolution

critical factors to initiate HPLC

- small particles - high pressure

partition chromatography

- stationary : liquid - mobile : liquid - called(liquid-liquid) - separation based on : relative solubility (relative partition coefficient) since partition coeff is : conc of solute in stationary / mobile two types : 1) normal phase chromatography : stationary : polar , mobile : non polar ( non polar elute first) 2) reversed phase chromatography : stationary : non polar , mobile : polar (polar elute first) Elution strength series : mobile phase : hexane>THF>propanol>dioxane>acetonitrile>methanol>water

gas liquid in gas chromatography :

- stationary : liquid held over inert support - requirements : low volatility / non volatile ( B.P >100C higher than max operating temp of the column) thermal stability , principle like dissolves like applies , polarity of stationary phase and sample has to be matches - stationary phases. : polar compounds - carbowax,polyethylene glycol non polar compounds - diphenyl dimethyl polysiloxane

gas solid in gas chromatography :

- stationary phase : solid (adsorbent) - used for low MW species that are not retained on GLC - uses molecular sieves ( silica gel , charcoal , inorganic )

flame atomizer

3 regions : 1- nebulizer - to spray the sample in flame as aerosol 2- burner - the place in which fuel and oxidant are mixed 3- flame - the main function of flame is atomization

Chromatography is a physical method that is used to separate and analyse __________ A. Simple mixtures B. Complex mixtures C. Viscous mixtures D. Metals

B. Complex mixtures

6-Which one of the following statements is INCORRECT? a. The λmax of absorption is lower than λmax of fluorescence of the same molecule. b. The λmax of absorption is lower than λmax of phosphorescence of the same molecule. c. The λmax of phosphorescence is lower than λmax of fluorescence of the same molecule. d. The λmax of fluorescence is lower than λmax of phosphorescence of the same molecule

Eabs>Eflour>Ephosph lamdaphos>lamdaflour>lamdaabs c. The λmax of phosphorescence is lower than λmax of fluorescence of the same molecule.

height equivalent theoretical plates (HETP)

HETP : L/NTP (as HETP is lower, the efficiency is higher)

Which of the following mixtures can be successfully separated using the stationary phase shown: Primary and secondary amines Polyhydroxy acids Alcohols Saturated hydrocarbons

Saturated hydrocarbons

Which statement is true about chromatography? a- It is a technique used for separating mixtures into their components to identify and quantify the mixture or its components. b- It cannot be used for purifying or isolating mixture components. c- The stationary phase may be gas or liquid held over an inert support. d-It is a chemical method ofseparation in which the components are distributed between stationary phase and the mobile phase.

a- It is a technique used for separating mixtures into their components to identify and quantify the mixture or its components.

In liquid-liquid chromatography, the mechanism of separation is: a- Partition b- Adsorption c- Size exclusion d- Sieving

a- Partition

Adsorption chromatography can be applied in: a- gas-solid chromatography b- paper chromatography c- gas-liquid chromatography d- liquid-liquid chromatography

a- gas-solid chromatography

The efficiency of the column is measured by: a- number of theoretical plates c- thickness of the stationary phase

a- number of theoretical plates

In liquid-liquid chromatography, the mechanism of separation is: a- partition b- adsorption c- size exclusion d- sieving

a- partition

11-Absorbance of Alendronate sample is measured at λmax ....... when treated with 2,4- dinitrofluorobenzene. a. 370 nm b. 470 nm c. 520nm d. 745 nm

a. 370 nm DNFB and NBD-CL ( derivatization agents ) - react with amine(colorless) to convert it to colored and be detected in visible only using calorimetry

Internal conversion is a deactivation process that involves: a. A transition from a higher singlet excited electronic state to a lower one b. A transition from a singlet excited electronic state to a triplet one c. Cleavage of chemical bonds initiating photochemical reactions d. Transition of excited electrons from vibrational level to another

a. A transition from a higher singlet excited electronic state to a lower one

5-Emission of photons during transitions from an excited singlet state to the ground singlet state is called: a. Fluorescence. b. Chemiluminescence. c. Phosphorescence. d. Bioluminescence.

a. Fluorescence. - fluorescence : singlet excited state to ground and phosphorescence : triplet excited state to ground state

6. Which of the following statements is correct? a. Molar absorptivity coefficient is wavelength dependent. b. Infrared radiation has a shorter wavelength than visible light. c. Microwave radiation possesses more energy than infrared radiation. d. Ultraviolet radiation has a longer wavelength than infrared radiation.

a. Molar absorptivity coefficient is wavelength dependent.

7-Which one of the following can be used as a light source in spectrofluorometer? a. Xenon arc lamp b. Deuterium arc lamp c. Tungsten lamp d. Hydrogen lamp

a. Xenon arc lamp fluorometer : xenon tungsten : visible deuterium : UV

10-The extinction coefficient is a. a constant of a substance b. a universal constant c. equal to one d- Wavelength independent

a. a constant of a substance

20-The time required for the unretained species in the mobile phase to pass through the column is called: a. dead time b. solute migration rate c. adjusted retention time d. retention time

a. dead time

atomic absorption and emission

absorption : A+hv-->A* A*-->A+heat emission : A+heat-->A* A*-->A+hv

molecular absorption and emission

absorption : M+hv--> M* M*-->M+heat emission : M+hv-->M* M*-->M+hv'

Which statement is true about separation of solutes by chromatographic techniques? a- Separation occurs when different solutes are equal in their distribution coefficients. b- Solute with higher distribution coefficient is more retained in the stationary phase. c- The more solute interacts with the stationary phase; the faster it is moved along a column. d-Solute with more affinity to the mobile phase is more retained in the stationary phase.

b- Solute with higher distribution coefficient is more retained in the stationary phase.

- ................is the difference in wavelength between positions of the band maxima of the absorption and fluorescence spectra. a- Resonance line b- Stokes shift c- Band broadening d- Emission spectrum

b- Stokes shift

30- In adsorption chromatography, the most adsorbed compound of the following is: a- carbonyl b- acid c- ester d- hydrocarbon

b- acid acid>alcohol>carbonyl>ester>hydrocarbon

In molecular size chromatography, the polymeric material used is made from: a- starch b- polysaccharide c- silica d- alumina

b- polysaccharide

10-Select the wavelength range corresponding to UV-VIS. region. a. 400-800 nm b. 200-800 nm c. 25 μm- 2.5 μm d. 2.5 μm - 1.0 mm

b. 200-800 nm visible : 400-800 UV : 200-400 UV and visible : 200-800

Intersystem Crossing (ISC) is a deactivation process that involves: a. A transition from a higher excited electronic state to a lower one b. A transition from a singlet excited electronic state to a triplet one c. Cleavage of chemical bonds initiating photochemical reactions d. Transition of excited electrons from vibrational level to another

b. A transition from a singlet excited electronic state to a triplet one

2-What is the role of dispersion system in UV-VIS. spectroscopy? a. Converts monochromatic radiation to polychromatic radiation. b. Converts polychromatic radiation to monochromatic radiation. c. Absorbs polychromatic radiation. d. Absorbs monochromatic radiation

b. Converts polychromatic radiation to monochromatic radiation.

12-A component of spectrophotometer that converts photons to current is: a. Dispersion system. b. Detector .c. Monochromator d. Signal amplifier

b. Detector

23-............... means that the mobile phase has a varying composition during the analysis. a. Isocratic elution chromatography b. Gradient elution chromatography c. Normal phase chromatography d. Reversed phase chromatography

b. Gradient elution chromatography

14-Which one of the following is a disadvantage of spectrofluorimetry? a. Broad linear range b. Self-quenching c. High selectivity d. High sensitivity

b. Self-quenching = quenching(decrease in fluoroscence.)

13. The dichromate ion absorbs light of wavelength close to 500 nm. Based on this information, what can you conclude? a. Solutions of the dichromate ion are colorless. b. The dichromate ion absorbs within the visible region. c. The dichromate ion absorbs in the ultraviolet region. d. The dichromate ion absorbs outside the visible region.

b. The dichromate ion absorbs within the visible region.

stationary phase for adsorption chromatography in HPLC

bare silica

stationary phase for liquid liquid partition in HPLC

bonded covalently and attached to silica surface by reactions

Which of the following equations give the expression for plate number, N when 'tR' is the retention time and 'Wb' is the width at the base of the peak. a) 16 tR 2 /Wb b) 4 tR 2 /Wb c) (4tR/Wb) 2 d) 4 (tR/Wb) 2

c) (4tR/Wb) 2

In GC, The length of packed column is a) 2-50 m b) 10-100 m c) 2-20 m d) 30-50 m

c) 2-20 m

4- An acceptable value for the retention (capacity) factor (k'): a) 0.05 b) 0.6 c) 7.0 d) 80.0

c) 7.0

The two HPLC chromatograms (A) and (B) were obtained for the same sample components; the difference in the separation efficiency could be attributed to: a) difference in temperature b) packed vs open tubular columns c) C8 vs C18 bonded stationary phase d) Detector type e) Normal vs revered phase

c) C8 vs C18 bonded stationary phase -packed vs open tubular column - have different tr

Benzylpenicillin, Lidocaine, and aspirin with log p = 1.83, 2.26, and 1.19; respectively, can be eluted using a reversed phase partition chromatography (RP-HPLC) according to the following order: a- Lidocaine, Benzylpenicillin, Aspirin b- Lidocaine, Aspirin, Benzylpenicillin c- Aspirin, Benzylpenicillin, Lidocaine d- Aspirin, Lidocaine, Benzylpenicillin

c- Aspirin, Benzylpenicillin, Lidocaine ; as log P increase , the more non polar

- Phenanthroline is a chromogen for the determination of: a- Ferric ions b- Cupric ions c- Ferrous ion d- Bismuth ions

c- Ferrous ion

A sample of polyprotic acid such as methyl red dye absorbs UV-visible light at different pH values. This sample shows a constant absorbance at the wavelength of: a- Maximum wavelength b- Maximum absorptivity c- Isosbestic point d- Highest pH

c- Isosbestic point

Dynodes present in a- Photocell detector b- Phototube c- Photomultiplier tube d- None of the above

c- Photomultiplier tube

In recent UV-visible spectrophotometer, the following ultrasensitive detector is installed: a- Photocell b- Phototube c- Photomultiplier tube d- All of the above

c- Photomultiplier tube

- Which statement is true about gas-liquid chromatography? a- Separation is based on the relative difference in adsorption of components at the surface of stationary phase. b- It involves the use of liquid mobile phase. c- The stationary phase is liquid held over an inert support d-The stationary phase may be packed in a tubular column or spread as thin layer on a plate.

c- The stationary phase is liquid held over an inert support

17- A 0.100 mol dm-3 aqueous solution of a nickel(II) salt shows three absorbances, one of which has a value of ε = 2.95 dm3 mol-1 cm -1 . What is the corresponding absorbance, if the path length of the solution cell used for the measurement is 1.00 cm? a. 0.340 b. 0.295 c. 29.5 d. 0.0340

c. 29.5

16- An absorption in an electronic spectrum is recorded at 17 000 cm-1 . What does this correspond to in nm? a. 5900 nm b. 59 000 nm c. 590 nm

c. 590 nm

8-Beer Lambert's law gives the relation between which of the following? a. Reflected radiation and concentration b. Scattered radiation and concentration c. Absorbed radiation and concentration d. Absorbed radiation and reflected radiation

c. Absorbed radiation and concentration

1. In which of the following ways, absorption is related to transmittance? a. Absorption is the logarithm of transmittance b. Absorption is the reciprocal of transmittance c. Absorption is the negative logarithm of transmittance d. Absorption is a multiple of transmittance

c. Absorption is the negative logarithm of transmittance

3-Fluorescein has higher fluorescence than phenolphthalein because: a. Fluorescein has lower fluorescence quantum yield than phenolphthalein. b. Phenolphthalein has a more rigid structure than Fluorescein. c. Fluorescein has a more rigid structure than phenolphthalein. d. The two benzene rings in Fluorescein can rotate on each other.

c. Fluorescein has a more rigid structure than phenolphthalein. (rigid-flexible structure ---> higher wavelength)

9-Which one of the following statements is CORRECT? a. Phenol is highly fluorescent in acidic medium due to formation of phenate ion. b. Phenolphthalein has higher fluorescence than fluorescein. c. Fluorescein has higher fluorescence than phenolphthalein. d. Aniline is highly fluorescent in acidic medium due to formation of anilinium ion.

c. Fluorescein has higher fluorescence than phenolphthalein.

18-In affinity chromatography, the stationary phase is: a. A liquid held on an inert support b. A finely divided solid acts as adsorbent. c. Immobilized biomolecules like enzymes and antibodies on to agarose or porous glass beads. d. An ionic group attached to inert water insoluble materials

c. Immobilized biomolecules like enzymes and antibodies on to agarose or porous glass beads. - stationary : liquid (partition) solid (adsorption) immobilized (affinity) ionic (ion exchange) size exclusion (polymers)

4-What is the radiationless process that involves a transition from a singlet excited electronic state to a triplet excited state? a. Internal conversion b. Vibrational relaxation c. Intersystem crossing d. Phosphorescence

c. Intersystem crossing Emission : radiationless process : 1- internal conversion : singlet ( from s2 to s1) 2- intersystem crossing : singlet to triplet radiation process : 1- fluorescence : in singlet excited state from excited to ground 2- phosphorescence : in triplet excited state from excited to ground absorption in singlet excited state ( from ground to excited)

15-A compound with higher tr value is: a. Polar compound .b. Nonpolar compound. c. More retained on stationary phase. d. Less retained on the stationary phase.

c. More retained on stationary phase.

17-Concentration of solute in the stationary phase to the concentration of the solute in the mobile phase is called: a. Capacity factor b. Retardation factor c. Partition coefficient. d. Selectivity factor.

c. Partition coefficient.

13-λmax depends on: a. The value of molar absorptivity b. The probability of transition c. The structure of the compound d. The speed of light

c. The structure of the compound

22-HPLC is characterized by: a. cheap instrumentation b. limited resolution c. high speed d. all of the above

c. high speed

9. Aqueous KMnO4 solutions are purple. A plot of absorbance against concentration is: a. non-linear. b. linear with a negative gradient. c. linear with a positive gradient. d. an exponential curve

c. linear with a positive gradient.

21-In ion exchange chromatography, the strong cation exchange resin contains ........................ functional group. a. quaternary ammonium b. tertiary amine c. sulphonic acid d. carboxylic acid

c. sulphonic acid ion exchange : 1- cation exchange resin : strong (sulphonic acid) , weak (carboxylic acid) 2- anion exchange resin : quanernary ammonium salts

11. At the doubled concentration a. the wave length of the absorption is different b. the extinction coefficient is twice as large c. the extinction is twice as large d. the extinction is constant.

c. the extinction is twice as large

chromagon

compound that converts colorless to colored for derivatization common chromogenic reagents are : NBD-Cl and DNFB

partition coefficient - distribution coefficient (k)

conc in stationary / conc in mobile

In GC separation, the sample can be: a) a mixture of gases b) a mixture of volatile liquids c) a mixture of thermally stable solids dissolved in a solvent d) All of the above e) None of the above

d) All of the above

In HPLC, the resolution between two partially overlapped peaks can be improved by: a) Adjusting the mobile phase velocity b) Use a mobile phase of weaker solvent strength c) Using a column prepared with smaller particle size d) All of the above e) None of the above

d) All of the above

Which of the following columns are used in gas chromatography? a) Analytical column b) Separation column c) Guard column d) Capillary column

d) Capillary column

The following factor(s) affect the number of theoretical plates (N): a) Mobile phase velocity b) Nature of the liquid stationary phase c) Oven temperature (in GC) or polarity of the mobile phase (in HPLC) d) Column length e) All of the above

d) Column length

FSOT Capillary columns are open tubular columns constructed from which of the following materials? a) Glass b) Metal c) Stainless steel d) Fused silica

d) Fused silica

Gas-solid chromatography is being used for a) Thermally stable organic components b) Volatile organic components c) Thermally stable inorganic components d) Low molecular weight gaseous species

d) Low molecular weight gaseous species

Which of the following types of chromatography involves the process, where the mobile phase moves through the stationary phase by the influence of gravity or capillary action? a) Column Chromatography b) High Pressure Liquid Chromatography c) Gas Chromatography d) Planar Chromatography

d) Planar Chromatography مب متاكده

The time taken by the analyte after sample injection to reach the detector is called _________ a) Dead time b) Solute migration rate c) Adjusted retention time d) Retention time

d) Retention time

The following term is relevant to HPLC: a) Carrier gas b) Temperature program c) Endotherm d) Reversed phase e) Open tubular column

d) Reversed phase

The X-axis in a typical chromatogram a) Detector's response b) Columnlength c) Number of theoretical plates d) Time e) Capacity factor

d) Time

Phenolic compounds in basic medium exhibit mainly: a) Red shift b) Hyperchromic shift c) Hypsochromic shift d) a and b

d) a and b

The mechanism of separation in ion exchange chromatography depend on ? a) adsorption b) partition c) molecular size and shape d) ion pair interaction

d) ion pair interaction

Chloro-7-nitrobenzo-2-oxa-1,3-diazole reagent (NBD-Cl) is used for the determination of: a- Alcohols b- Nitro-compounds c- Esters d- Amines

d- Amines

In partition chromatography, the stationary phase is: a- Finely divided solid b- Polymers with suitable pore size c- An inert support with immobilized ligand d- Liquid held over an inert supp

d- Liquid held over an inert supp

Which one of the following methods is the most suitable for Analysis of high molecular weight biomolecules? a- Gas chromatography b- Ion exchange chromatography c- Paper electrophoresis d- Size exclusion chromatography

d- Size exclusion chromatography

- Dinitrofluorobenzene reagent (DNFB) is used for the determination of: a-Alcohols b- Nitro c- ester d- amines

d- amines

31- Strong cationic exchange resin contains water insoluble polymers with ionizable functional groups such as: a- quaternary ammonium salt b- aliphatic amine c- carboxylic acid d- sulphonic acid

d- sulphonic acid

Which of the following is a method of atomization? a- Flame b- Electric furnace c- Plasma d-All of the above

d-All of the above

UV/VIS radiations may cause the following transitions in the molecules: a) Electronic transitions b- Rotational c) Rotational and vibrational transitions d-All of the above

d-All of the above molecules: electronic transition - rotational and vibrational atoms : only electronic transition - no rotational or vibrational thats why they are lines and not bands

14. A solution of X of concentration 0.010 mol dm-3 gives an absorbance of 0.5. What concentration is a solution of X which gives an absorbance reading of 0.25? Assume that the same optical cell is used for both readings. a. 0.050 mol dm-3 b. 0.020 mol dm-3 c. 0.010 mol dm-3 d. 0.0050 mol dm-3

d. 0.0050 mol dm-3

19-The fluorescence is most often measured at a................. angle relative to the excitation light. a. 30° b. 45° c. 60° d. 90°

d. 90°

16-The relationship between the drug concentration and the emission intensity is called: a. Emission spectrum .b. Fluorescence spectrum. c. Phosphorescence spectrum. d. Calibration curve.

d. Calibration curve. **calibration (concentration ) 1- Abs vs conc (calibration curve) 2-FI or emission vs conc ( calibration curve of fluorescence) 3- Peak Area or Peak height vs conc ( calibration curve of chromatography ) **spectrum ( wavelength) 1- Absorption vs wavelength ( absorption spectrum ) 2- F.I vs wavelength ( emission spectrum)

Joblonski diagram: a. Is a relationship between concentration against absorbance b. Describes the isosbestic point c. Is a relationship between absorbance against wavelength d. Shows the ground and excited electronic levels in the molecules

d. Shows the ground and excited electronic levels in the molecules

8. Which statement is correct? a. Wavelength is directly proportional to energy. b. Wavenumber is directly proportional to wavelength. c. Wavelength is directly proportional to frequency. d. Wavenumber is directly proportional to energy.

d. Wavenumber is directly proportional to energy.

12. A shift to lower wavenumber for an absorption in a spectrum corresponds to: a. a loss of intensity. b. a shift to lower wavelength. c. a shift to higher energy. d. a shift to lower frequency.

d. a shift to lower frequency.

Aromatic amines in acidic medium exhibit: a. Red Shift b. Hypochromic Shift c. Blue Shift d. b and c

d. b and c acidic : batho(red) and hyper basic : hypso (blue) and hypo

stokes shift

difference in wavelength between maxima absorption and emission (Fluorescence) of the same electron transition

peak height

distance from peak maximum to peak base

Separation in chromatography occurs due to differences in .......... of the individual sample components.

distribution coefficient

quantum yeild

efficiency of fluorescence number of photons emitted (luminesce)/number of photons absorbed(excited) equal one in the absence of non-radiative process the higher the more fluorescence equal zero when there is no fluorescent

flame emission vs flamic absorption

emission : no light source , excitation as source of excitation depends on num of excited state atoms atomization + excitation absorption : light source : hollow cathode lamp num of ground state atomization only

HPLC limitation

expensive instrument experience required

capacity factor - retention factor (k')

migration rates of solute in column (k' = t'r/tm) if k' << 1 (quick elution , hard to determine retention time) k'>20 (very long elution) 2>k'>10 (convenient) varied in GC: by temp , LC: by solvent

normal phase seperation

mobile : nonpolar stationary : polar non polar elute first (spends less time in stationary phase) retention time are controlled by selecting the mobile phase highly nonpolar ---> longer retention time

reverse phase chromatography

mobile : polar stationary : nonpolar polar elutes first highly polar---> longer retention time

The phase which is moving through the stationary phase in chromatographic separation is called:

mobile phase

The Selectivity factor is always:

more than one

atomic spectrum

no bonds - no vibrational or rotational states - line while molecular have bands not lines

Heated injection port

sample evaporates in GC ( operated at 50C higher than applied temp for GC column)

ion exchange chromatography

packing : ion exchange resin solvent : water separated species : ions (amino acid, organic acid and bases)

atomization

process by which a sample is converted into an atomic vapor

adsorption chromatography

stationary : solid (alumina/silica gel) - affect the separation in adsorption mobile : gas/liquid based on : relative difference in adsorption of components adsorption order : acid>alcohol>carbonyl>ester>hydrocarbon as temp inc. adsorption dec. as particle size inc. adsorption dec. surface area dec.

The fixed phase in chromatographic separation is called:

stationary phase