Final exam vocab

Question 1

length of a chromatography column divided by plate number of the column. Calculated as the variance of the analyte band divided by the distance, x, it has traveled

Answer 1

plate height

Question 2

a chromatographic separation utilizing a polar stationary phase and a less polar mobile phase

Answer 2

normal phase hplc

Question 3

in gas chromatography, a length of empty, silanized capillary ahead of the chromatography column placed there to improve the peak shape of solutes that elute close to solvent when large volumes of solvent are injected or when the solvent has a very different polarity from that of the stationary phase.

Answer 3

retention gap

Question 4

In chromatography, the distance per unit time traveled by the mobile phase.

Answer 4

linear flow rate

Question 5

A technique in which separation is based on differences in the solubility of sample components in the stationary phase in gas chromatography and in the mobile and stationary phases in liquid chromatography.

Answer 5

partition chromatography

Question 6

A technique in which solute ions are retained by oppositely charged sites in the stationary phase.

Answer 6

ion exchange

Question 7

A technique in which the stationary phase has a porous structure into which small molecules can enter but large molecules cannot. Molecules are separated by size, with larger molecules moving faster than smaller ones

Answer 7

size exclusion

Question 8

In chromatography, a hollow capillary column whose walls have high-surface-area porous solid particles adhering to the column wall.

Answer 8

porous-layer open tubular

Question 9

Liquid chromatography using a single solvent (or single solvent mixture) for the
mobile phase continuously throughout the separation.

Answer 9

isocratic elution

Question 10

Splitless gas chromatography injection technique in which solutes are condensed at the start of the column by setting the initial column temperature at least 100°C below the boiling points of the solutes of interest. Solvent and
low-boiling components are eluted rapidly, but high-boiling solutes remain in a narrow band at the beginning of the column.

Answer 10

solvent trapping

Question 11

Chromatographic peak where there is a gradual rise and abrupt fall of the peak.
B/A < 1

Answer 11

fronting

Question 12

The log of the ratio of the irradiance striking the sample and the radiant power emerging from the other side.

Answer 12

absorbance

Question 13

The fraction of incident radiation that passes through a sample.

Answer 13

transmittance

Question 14

Process in which a molecule emits a photon due to transition between states of the same spin multiplicity (e.g., singlet  singlet ).

Answer 14

fluorescence

Question 15

Emission of light during a transition between states of different spin multiplicity
(e.g., Triplet  Singlet ).

Answer 15

phosphorescence

Question 16

A graph of luminescence intensity versus luminescence wavelength (or frequency or wavenumber), obtained with a fixed excitation wavelength.

Answer 16

emission spectrum

Question 17

A graph of luminescence (measured at a fixed wavelength) versus excitation frequency or wavelength.

Answer 17

excitation spectrum

Question 18

Any state of an atom or a molecule having more than the minimum possible energy.

Answer 18

excited state

Question 19

State of an atom or a molecule with the minimum possible energy.

Answer 19

ground state

Question 20

Electronic state in which all electron spins are paired.

Answer 20

singlet

Question 21

An electronic state in which there are two unpaired electrons.

Answer 21

triplet

Question 22

Process in which emission from an excited molecule is decreased by energy transfer to another molecule

Answer 22

quenching

Question 23

In luminescence, a decrease in emission intensity due to absorption of excitation or emission irradiance by analyte molecules

Answer 23

self-absorption

Question 24

the range of wavelengths or frequencies of an absorption or emission band, typically measured at a height equal to half of the peak height

Answer 24

bandwidth

Question 25

The application of numerical algorithms to data to reduce noise

Answer 25

digital smoothing

Question 26

In atomic absorption, periodic blocking of the beam allows a distinction to be made between light from the source and light from the flame.

Answer 26

beam chopping

Question 27

Improvement of a signal by averaging successive scans.

Answer 27

signal averaging

Question 28

Relative population of two states at thermal equilibrium – related to the degeneracy of the ground and excited states, the energy gap between them, the temperature, and a constant.

Answer 28

boltzman distribution

Question 29

A molecule moving toward a source of radiation experiences a higher frequency than one moving away from the source.

Answer 29

doppler effect

Question 30

In spectroscopy, line broadening due to collisions between molecules

Answer 30

pressure broadening

Question 31

Most intense peak in a mass spectrum

Answer 31

base peak

Question 32

Integer mass of the species with the most abundant isotope of each of the constituent atoms.

Answer 32

nominal mass

Question 33

In mass spectrometry, an ion that has not lost or gained any atoms during ionization.

Answer 33

molecular ion

Question 34

Process of breaking a liquid into a mist of fine droplets.

Answer 34

nebulization

Question 35

A suspension of very small liquid or solid particles in air or gas.

Answer 35

aerosol

Question 36

A sample not intended to contain analyte

Answer 36

blank

Question 37

Range of analyte concentration over which a change in | concentration gives a change in detector response

Answer 37

dynamic range

Question 38

Concentration range over which the change in detector response is proportional to the change in analyte concentration

Answer 38

linear range

Question 39

A liquid remaining above a solid after precipitation

Answer 39

supernatant

Question 40

A suspension of a solid in a solvent

Answer 40

slurry

Question 41

All substances found within a material

Answer 41

matrix

Question 42

Moles of solute per liter of solution

Answer 42

molarity

Question 43

Moles of solute per kilogram of solution

Answer 43

molality

Question 44

Mass of a substance per unit volume

Answer 44

density

Question 45

Mass of solute per mass of total solution (multiplied by | 100)

Answer 45

weight percent

Question 46

Volume of solute per volume of total solution | multiplied by 100

Answer 46

volume percent

Question 47

Micrograms of analyte per gram (or milliliter) of sample

Answer 47

ppm

Question 48

Nanograms of analyte per gram (or milliliter) of sample

Answer 48

pbb

Question 49

The bell-shaped curve obtained by plotting frequency | versus deviation from the mean

Answer 49

guasssian curve

Question 50

All of the digits of a number that are known with | certainty plus the first uncertain digit

Answer 50

significant figures

Question 51

Describes the spread in results when one person uses one procedure to analyze the same sample by the same method with the same equipment multiple times

Answer 51

repeatability

Question 52

Describes the variation observed when an assay is performed by different people on different instruments on different days in the same lab

Answer 52

intermediate precision

Question 53

Describes the spread in results when different people in different labs using different equipment each follow the same procedure with the same kind of sample

Answer 53

reproducibility

Question 54

It is an analysis of a solution formulated to contain a known concentration of analyte. It is the analyst’s own check that procedures and instruments are functioning correctly.

Answer 54

check standard

Question 55

A datum that is far from other points

Answer 55

outlier

Question 56

A graph showing the value of some property versus concentration of analyte. When the corresponding property of an unknown is measured, its concentration can be determined from the graph.

Answer 56

calibration curve

Question 57

A measure of how close a measured value is to the | “true” value

Answer 57

accuracy

Question 58

A change in analytical sensitivity (slope of calibration) caused by anything in the sample other than analyte.

Answer 58

matrix affect

Question 59

Slow change in the response of an instrument due to various causes such as changes in electrical components with temperature, variation in power-line voltage to an instrument, and aging of components within instruments.

Answer 59

drift

Question 60

Smallest amount of analyte that can be measured with | reasonable accuracy. Usually taken as 10 times the standard deviation of a blank or low-concentration sample

Answer 60

quantitation limit

Question 61

Visual representation of confidence intervals for a Gaussian distribution - warns us when a property being monitored strays dangerously far from an intended target value.

Answer 61

control chart