CC Lesson 3

Question 1

Is the historical basis of quantifying the concentration of unknown analytes in the clinical chemistry lab

Answer 1

Analytical methods

Question 2

Is transmitted via electromagnetic waves that are characterized by their frequency and wavelength

Answer 2

Energy

Question 3

Is the distance between two successive peaks, and it is expressed in nanometer (nm)

Answer 3

Wavelength

Question 4

The number of vibrations of wave motion per second

Answer 4

Frequency

Question 5

How is wavelength and frequency related?

Answer 5

Theyre inversely related. And longer the wavelength, the lower the frequency. And a shorter wavelength meant a higher frequency.

Question 6

The relationship between wavelength and energy is described by

Answer 6

Planck’s formula
E (energy) = (6.626x10^-34)(frequency)

Question 7

Visible spectrum

Answer 7

400 - 700 nm

Question 8

Ultraviolet spectrum

Answer 8

<400 nm

Question 9

Infrared spectrum

Answer 9

> 700 nm

Question 10

Is the measurement of light intensity in a narrower wavelength

Answer 10

Spectrophotometric measurement

Question 11

The measurement of light intensity using a specific wavelength

Answer 11

Photometric measurement

Question 12

What is the primary analytical utility of spectrophotometry or filter photometry?

Answer 12

Isolation of discreet portions of the spectrum for purposes of measurement

Question 13

It involves measurement of the light transmitted by a solution to determine the concentration of the light absorbing substances in the solution

Answer 13

Spectrophotometry

Question 14

A device that measures the wavelengths of light or the intensity of radiation

Answer 14

Spectrometer

Question 15

Two types of spectrometer

Answer 15

Single-beam spectrophotometer
Double-beam spectrophotometer

Question 16

Spectrophotometer consists of two instruments. What are they?

Answer 16

Spectrometer - for producing light of any selected color (wavelength)

Photometer - for measuring the intensity of light

Question 17

The simplest type of an absorption spectrophotometer

Answer 17

Single-beam spectrophotometer

Question 18

It is designated to make one measurement at a time at one specified wavelength

Answer 18

Single-beam spetrophotometer

Question 19

It is an instrument that splits the monochromatic light into two components: one beam passes through the sample and the other through a reference solution or blank

Answer 19

Double-beam spectrophotometer

Question 20

Difference between single and double-beam spectrophotometer

Answer 20

Single beam spectrophotometer takes one measurement on one specific wavelength at a time, while double beam spectrophotometer splits the monochromatic light into two: one passes through the sample, while the other passes through a reference solution

Question 21

Six components of a spectrophotometer

Answer 21

1. Stable source of radiant energy
2. Filter that isolates a specific region of the electromagnetic spectrum
3. Sample holder
4. Radiation detector
5. Signal processor
6. Readout device

Question 22

It provides polychromatic light and must generate sufficient radiant energy or power to measure the analyte of interest.

Answer 22

Light/radiant source

its response to change in light intensity must be linear for accurate absorbance measurements

Question 23

Factors for choosing a light source

Answer 23

Range
spectral distribution wh/in range
the source of radiant production
stability of the radiant energy
temperature

Question 24

Emits radiation that changes in intensity; widely used in the lab

Answer 24

Continuum source

Question 25

Examples of continuum source

Answer 25

Tungsten, deuterium, xenon lamps

Question 26

Its the commonly used light source in the visible and infrared region

Answer 26

Tungsten light bulb

Question 27

Is routinely used to provide UV radiation in analytical spectrophotometers

Answer 27

Deuterium lamp

Question 28

Produces a continuous source of radiation, which covers both the UV and the visible range

Answer 28

Xenon discharge

Question 29

Emits limited radiation and wavelength. ---- that emit a few discrete lines find wide use in AAS, molecular, and fluorescent spectroscopy

Answer 29

Line source

Question 30

Meaning of the acronym LASER

Answer 30

Light Amplification by Stimulated Emission of Radiation

Question 31

It minimizes unwanted or stray light and prevents the entrance of scattered light into the monochromator system

Answer 31

Entrance slit

Question 32

Refers to any wavelengths outside the band transmitted by the monochromator; it does not originate from the polychromatic light source; it causes absorbance error

Answer 32

Stray light

Question 33

What is the most common cause of loss of linearity at high-analyte concentrations

Answer 33

Stray light

Question 34

It isolates specific or individual wavelength of light. What is this and what are the different types?

Answer 34

Monochromator Prisms Diffraction gratings Filters

Question 35

Wedge-shaped pieces of glass, quartz, or sodium chloride

Answer 35

Prisms

Question 36

These can be rotated, allowing only the desired wavelength to pass through an exit slit

Answer 36

Prisms

Question 37

These are made by cutting grooves or slits into an aluminized surface of a flat piece of crown glass

Answer 37

Diffraction gratings

Question 38

Most commonly used monochromator with a better resolution than prism

Answer 38

Diffraction gratings

Question 39

These are made by placing semi-transparent silver films on both sides of a dielectric such as magnesium fluoride

Answer 39

Filters

Question 40

They produce monchromatic light based on the principle of constructive interference of waves - light waves enter one side of it and are reflected at the second surface

Answer 40

Filters Filters are simple, least expensive, not precise, but useful monochromators. They usually pass a wide band of radiant energy and have low transmittance of the selected wavelength.

Question 41

Examples of line source

Answer 41

Mercury and sodium vapor lamps and the hallow cathode lamp

Question 42

It controls the width of the light beam (bandpass); allows only a narrow fraction of the spectrum to reach the sample cuvette

Answer 42

Exit slit

Question 43

It's the total range of wavelengths transmitted

Answer 43

Bandpass

Question 44

It is also called the absorption cell/analytical cell/sample cell. It holds the solution whose concentration is to be measured

Answer 44

Cuvette

Question 45

Most commonly used cuvette

Answer 45

Alumina silica glass

Question 46

Type of cuvette used for measurement of solution requiring visible and ultraviolet spectra

Answer 46

Quartz/plastic

Question 47

Silica cuvettes transmit light effectively at what wavelengths

Answer 47

≥220 nm

Question 48

Why are you not allowed to leave alkali solutions standing in cuvettes for long periods?

Answer 48

Alkali solutions slowly dissolves glass, producing etching

Question 49

It detects and converts transmitted light into photoelectric energy

Answer 49

Photodetector

Question 50

It detects the amount of light that passes through the sample cuvette

Answer 50

Photodetector

Question 51

Types of photodetector

Answer 51

Phototube Photomultiplier Tube (PMT) Photodiode

Question 52

It displays the output of the detection system

Answer 52

Meter or readout device

Question 53

How is an absorbance check performed?

Answer 53

It's performed using glass filters or solutions with a known absorbance values for a specific wavelength

Question 54

Absorption spectroscopy is perferred for solutions with absorbance values of ----

Answer 54

Less than 2.0

Question 55

They verify linearity

Answer 55

Neutral density filters and dichromate solution

Question 56

It states that the concentration of the unknown substance is directly proportional to the absorbed light and inversely proportional to the amount of transmitted light.

Answer 56

Beer' law Higher concentration, higher absorbed light Higher concentration, lower transmitted light

Question 57

It mathematically establishes the relationship between concentration and absorbance

Answer 57

Beer's Law

Question 58

It is the amount of light absorbed It is proportional to the inverse log of transmittance It is mathematically derived from %T

Answer 58

Absorbance

Question 59

It is the ratio of the radiant energy transmitted divided by the radiant energy on the sample

Answer 59

Percent Transmittance (%T)

Question 60

It means the blank contains serum but without the reagent to complete the assay.

Answer 60

Blanking technique

Question 61

It corrects absorbance caused by the color of the reagents - the absorbance of reagents is automatically subtracted from each of the unknown reading

Answer 61

Reagent blank

Question 62

What is the principle of Flame Emission Photometry (FEP)

Answer 62

The excitation of electrons from lower to higher energy state

Question 63

It measures the light emitted by a single atom burned in flame. It is used in the measurement of excitee ions (sodium and potassium)

Answer 63

Flame Emission Photometry

Question 64

It measures the light absorbed by atoms dissociated by heat It is used for measurement of unexcited trace metals (calcium and magnesium)

Answer 64

Atomic Absorption Spectophotometry

Question 65

Principle of Atomic Absorption Spectrophotometry

Answer 65

Element is not excited, but dissociated from its chemical bond and place in a unionized, unexcited, ground state

Question 66

The unknown sample is made to react with a known solution in the presence of an indicator

Answer 66

Volumetric/Titrimetric

Question 67

Example of titrimetric/volumetric

Answer 67

Schales and Schales method (chloride test) EDTA titration method (calcium test)

Question 68

It determines the amount of light blocked (reduction of light) by a particulate matter in a turbid solution

Answer 68

Turbidimetry

Question 69

For measuring abundant large particles (proteins) and bacterial suspensions

Answer 69

Turbidimetry

Question 70

It determines the amount of scattered light by a particulate matter suspended in a turbid solution

Answer 70

Nephelometry

Question 71

It is used for measuring the amount of antigen-antibody complexes (proteins)

Answer 71

Nephelometry

Question 72

It determines the amount of light emitted by a molecule after excitation by electromagnetic radiation

Answer 72

Fluorometry

Question 73

It measures the amount of light intensity over a zero background

Answer 73

Fluorometry

Question 74

--- is the light emission from an excited state, --- is the light emission from an excited triplet state

Answer 74

Fluorescence Phosphorescence

Question 75

For the measurement of phosphyrins, magnesium, calcium, and catecholamines

Answer 75

Fluorometry

Question 76

This method is best when differentiating two compounds having an excitation reaction at the same wavelength

Answer 76

Chemiluminescence

Question 77

Measurement of changes in the colligative properties of solutions that occur owing to variations in particle concentration

Answer 77

Osmometry

Question 78

When active osmotic particles are added to a solution,

Answer 78

osmolality increases, and four other properties of the solution are also affected

Question 79

Colligative properties of the solution in osmometry

Answer 79

Osmotic pressure, boiling point, freezing point, and vapor pressure

Question 80

What reactions occur when osmolality of a solution increases?

Answer 80

Osmotic pressure increase, boiling point increases Freezing point depress, and vapor pressure depress

Question 81

It is the most commonly used method for measuring the changes in colligative properties of a solution

Answer 81

Freezing-point depression osmometry

Question 82

It is based on the principle that addition of solute molecules lowers the temperature at which a solution freezes

Answer 82

Freezing-point depression osmometry

Question 83

What is the principle of electrophoresis

Answer 83

Migration of charged particles in an electric field

Question 84

It separates proteins on the basis of their electric charges densities

Answer 84

Electrophoresis

Question 85

What happens to proteins during electrophoresis

Answer 85

Proteins are negatively charged and move towards the anode

Question 86

Buffer used in electrophoresis

Answer 86

Barbital (pH 8.6)

Question 87

Factors affecting rate of migration in electrophoresis

Answer 87

- net electric charge of the molecule - size and shape of the molecule - electric field strength - nature of the supporting medium - temperature of operation

Question 88

Factors affecting rate of migration in electrophoresis

Answer 88

- net electric charge of the molecule - size and shape of the molecule - electric field strength - nature of the supporting medium - temperature of operation

Question 89

Electrophoresis supporting medias

Answer 89

Cellulose acetate - separates by molecular size Agarose gel -separates by electrical charge; does not bind protein Polyacrylamide gel - separates on the basis of charge and molecule size; separates proteins into 20 fractions; used to study isoenzymes

Question 90

It determines the components of a sample where the x-axis represents the mass-to-charge ratio, and the y-axis is their relative abundance within the sample

Answer 90

Mass spectrophotometry

Question 91

It is based on the fragmentation and ionization of molecules using a suitable source of energy

Answer 91

Mass spectrophotometry

Question 92

It is basically the study of proteinsbin aid of disease diagnosis

Answer 92

Proteomics

Question 93

It identifies potential biomarkers that will assist in the detection of diseases It involves the characterization of complete set of proteins present in a cell, organ, or organism at a given time It determines the actual real time condition of the cells

Answer 93

Proteomics

Question 94

It determines the concentrations of metabolites with very small sizes in biological samples utilizing separation and mass-to-charge ratio techniques

Answer 94

Metabolomics

Question 95

It involves the complehensive study of metabolites and their chemical properties in biofluids

Answer 95

Metabolomics

Question 96

It is the separation of soluble components in a solution by specific differences in physical-chemical characteristics of the different constituents, with a mobile phase and a stationary phase

Answer 96

Chromatography

Question 97

It is used for fractionation of sugar and amino acid

Answer 97

Paper chromatography Sorbent: whatman paper

Question 98

It is a semiquantitative drug screening test. Sample components are identified by comparison with standards on the same plate

Answer 98

Thin layer chromatography (TLC)

Question 99

It is used for separation of steroids, barbiturates, blood, alcohol, and lipids. It is useful for compounds that are naturally volatile or can be easily converted to a volatile form Flame ionization is used as a detector for gas liquid chromatography

Answer 99

Gas chromatography

Question 100

Mobile phase of gas chromatography

Answer 100

Gases like helium (most commonly used), nitrogen, hydrogen, and argon