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Applied Forensic Chem > Chapter 6 > Flashcards

Chapter 6 Flashcards

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1
Q

The angle of the cone of light exiting a sample observed by microscopy

A

Angle aperture (AA)

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2
Q

Materials that have more than one refractive index

A

Anisotropic

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3
Q

Scattering interactions that start from an excited state; a type of inelastic scattering

A

Anti-Stokes scattering

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4
Q

An opening, often adjustable, that determines how much light or electromagnetic energy passes through; usually designed to limit stray light

A

Aperture

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5
Q

Ionization using an electrical discharge used for LCMS instrumentation and some IMS instrumentation

A

Atmospheric pressure chemical ionization (APCI)

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6
Q

Generically, the width of a band of electromagnetic energy measured in terms of wavelength

A

Bandwidth

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7
Q

In a spectrum, chromatogram, or other peak-based output, the situation that occurs when there is some portion of flat baseline in the space separating the peaks

A

Baseline resolution

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8
Q

A lens that, when inserted into the optical train of a microscope, allows the viewer to see an image of the filament; used to establish Koehler illumination. A lens that focuses on the rear aperture of the objective lens assembly

A

Bertrand lens

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9
Q

The difference in the refractive indexes of an anisotropic material; can be calculated by subtraction or with a Michel-Levy chart

A

Birefringence

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10
Q

Electrophoresis in a capillary tube that exploits electroosmotic flow

A

Capillary zone electrophoresis/CZE

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11
Q

A focusing device that utilizes highly polished mirrors in lieu of glass lenses

A

Cassegrain system

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12
Q

A component of mass spectrometers in which collision gases are introduced into a high vacuum region to facilitate collisional dissociation of complexes and compounds

A

Collision cell

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13
Q

The assembly in a microscope below the sample stage; focuses the beam into a tight cone of light

A

Condenser/condenser lens

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14
Q

The space between the lens and the image sensor where the image being filmed will appear in focus to the human eye

A

Depth of focus

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15
Q

A material that has two colors due to different absorbances depending on orientation

A

Dichroic

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16
Q

An older form of micro-IR in which the diffuse reflections off a sample act as the attenuated IR signal

A

Diffuse reflection

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17
Q

Natural spreading of a concentrated band of analyte

A

Diffusion

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18
Q

Physical separation of constituent wavelengths by a device such as a prism or grating

A

Dispersion

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19
Q

Ionization and fragmentation of molecules entering a mass spectrometer achieved by collision with a stream of electrons produced by a heated filament

A

Electron impact ionization/quadrupole mass filter

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20
Q

Transition of an atom or ion from the ground to an excited state via electron promotion among atomic orbitals

A

Electronic transition

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21
Q

Flow of ions that occurs in a silica capillary tube exploited in capillary electrophoresis

A

Electroosmotic flow

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22
Q

Separation of charged and neutral species based on size-to-charge ratio

A

Electrophoresis

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23
Q

An ionization source for LC/MS that applies charge to solvent droplets that evaporate and eventually disperse via Coulombic explosion

A

Electrospray ionization (ESI)

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24
Q

In an ATR, a series of reflective adsorptive interactions; multiple internal reflections

A

Evanescent wave

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25
Q

A sample preparation technique that removes the analyte from the matrix

A

Extinction

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26
Q

The lens or lens assembly closest to the sample in optical microscopes

A

Eyepiece

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27
Q

How large a portion of the sample can be seen in focus at one time

A

Field of view

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28
Q

A GC detector selective to organic carbon and C-H bonds; based on creation of charged species in the flame

A

Flame ionization detector (FID)

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29
Q

A cell used to isolate separated analytes in a flowing system long enough to obtain a spectrochemical measurement with an adequate pathlength

A

Flow cell

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30
Q

The distance along the optic axis of a lens to the principal focus

A

Focal length

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31
Q

A combination of a separation module with a detector module such as GC-MS (GCMS); hyphen is often omitted

A

Hyphenated instrument

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32
Q

An extremely hot excitation source for elemental analysis via emission or mass spectrometry. A plasma is not a flame and reaches much higher temperatures, so it can excite a significant portion of the ground state atoms. The plasma is created in the torch portion of the inlet

A

Inductively coupled plasma (ICP) torch

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33
Q

A plot of the distance traveled in an interferometer by the mirror versus intensity; can also be plotted versus time

A

Interferogram

34
Q

Techniques that exploit interference (constructive and destructive) to limit or control the wavelengths of light transmitted from a source to a detector

A

Interferometry

35
Q

Gas phase separation of ion/molecule clusters at atmospheric pressure; generically gas phase electrophoresis

A

Ion mobility spectrometry

36
Q

In mass spectrometry, a substance that has the same molecular weight or atomic weight of the substance of interest

A

Isobaric interference

37
Q

Materials that have the same refractive index regardless of orientation

A

Isotropic

38
Q

A method of filtering ions in a collision cell such as an ICP-MS or LC-MSn instruments

A

Kinetic energy discrimination (KED)

39
Q

In a microscope, the alignment of lamp and lenses that produces optimal and even illumination

A

Koehler illumination

40
Q

A detector that ionizes and fragments molecules and creates a reproducible and usually unique fragmentation pattern that can be used for identification

A

Mass spectrometer (MS)

41
Q

The process of a solute moving in and out of stationary phase

A

Mass transfer

42
Q

Capillary electrophoresis using micelles and selective partitioning to separate neutral species

A

Micellar electrokinetic chromatography (MEKC)

43
Q

Structures formed by surfactants above a critical concentration in water

A

Micelles

44
Q

Use of a microscope in conjunction with a spectrometer

A

Microspectrophotometry

45
Q

Output of an ion mobility spectrometry

A

Mobility spectrum

46
Q

A device such as a prism, filter, or grating that selectively removes all but a narrow range of electromagnetic energy from an impinging source

A

Monochromator

47
Q

A sample introduction device used with ICP-MS and other techniques; creates a fine mist for introduction into the instrument

A

Nebulizer

48
Q

A GC detector selective to N- and P-containing compounds; similar in design to an FID and includes and alkali salt

A

Nitrogen-phosphorus detector (NPD)

49
Q

An ability of a lens to collect light

A

Numerical aperture (NA)

50
Q

The lens or lens assembly closest to the sample in optical microscopes

A

Objective lens

51
Q

The lens or lens assembly closest to the viewer’s eyes in optical microscopes

A

Ocular lens

52
Q

Light path that doesn’t follow the principle optical axis; set off at an angle

A

Off-axis

53
Q

The imaginary line that runs through the point of a curved lens where the curvature is at a maximum; may or may not be the geometric centerline

A

Optic axis

54
Q

A compound used to standardize the performance of mass spectrometers to insure intercomparability of spectra

A

Per-Fluorotributylamine (PFTBA)

55
Q

A detector that works by detecting photons dispersed in space; one photodiode per geometrical location

A

Photodiode array (PDA)

56
Q

A material that has two or more colors due to different absorbances depending on orientation

A

Pleochroism

57
Q

Chemical bonds that are altered by passage of light; bonds in which the electron clouds can be distorted by scattering interactions

A

Polarizable bonds

58
Q

Light that vibrates in a single plane

A

Polarized light

59
Q

A technique that uses polarizing filters in the optical train of a microscope

A

Polarized light microscopy (PLM)

60
Q

The point in space where light rays that have passed through a lens will converge

A

Principal focus

61
Q

A material such as a synthetic fiber that is ordered but not crystalline in the sense that a solid inorganic material is

A

Pseudocrystalline

62
Q

A transition of an excited state to a lower state that occurs without emission of a photon; a transition in which energy is dissipated typically as heat

A

Radiationless transition

63
Q

A vibration technique based on scattering and polarizable bonds

A

Raman spectroscopy

64
Q

Scattering that results in no change in wavelength; elastic scattering

A

Rayleigh scattering

65
Q

A component of mass spectrometers in which collision gases are introduced into a high vacuum region to facilitate collisional dissociation of complexes and compounds

A

Reaction cell

66
Q

An image created by a lens that can be projected onto a screen; an image that exists at a plane in space and doesn’t require one to look through a lens to see it

A

Real image

67
Q

The ability of a lens or optical train to distinguish two objects, = 0.6/NA

A

Resolving power

68
Q

An expression of the slowing of light as it propagates along and perpendicular to the optic axis of the material. The greater the difference in speed, the greater the retardation

A

Retardation

69
Q

In polarizing light microscopy, the distance (in nm) that separates the emerging perpendicular and parallel rays emerging from a birefringent sample

A

Retardation distance

70
Q

An imaging technique that uses interaction of a sample with electrons to create an image

A

Scanning electron microscope (SEM)

71
Q

An expression that described the angles of refraction of light when it passes through an interface; (sin(i))/(sin(r)) = n2/n1

A

Snell’s law

72
Q

“Perfect reflection”; angle of reflection = angle of incidence; occurs at a surface where there is a change in the refractive index

A

Specular reflection

73
Q

Scattering interactions that start from the ground state; a type of inelastic scattering

A

Stokes scattering

74
Q

A process where energy is absorbed to some degree by a substrate before being reflected

A

Surface absorption-reflection (SAR)

75
Q

A series of mass filters placed in tandem (in space or time) such as a triple quadrupole mass spectrometer

A

Tandem mass spectrometry

76
Q

A measure of the efficiency and resolving power of a chromatographic column; based on distillation model

A

Theoretical plates

77
Q

A device that converts whatever arrives at a detector (photons, ions, etc.) into an electrical signal

A

Transducer

78
Q

A plot of HETP versus flow rate; describes three contributing factors to band broadening and thus column efficiency

A

van Deemter curve

79
Q

An image created by a lens that doesn’t exist in a point in space and one that can’t be captured on a screen. It exists only when viewed through the lens

A

Virtual image

80
Q

The amount of space available between the stage and the lens of a microscope for sample insertion

A

Working distance

81
Q

A technique in which electrons analogous to light where the diffraction pattern relates to crystal structure

A

X-ray diffraction (XRD)

Applied Forensic Chem (9 decks)

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