CFU ANCH P1-P3

80問 • 1年前

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It is a measurement science consisting of a set of powerful ideas and methods that are useful in all fields of science, engineering, and medicine

Analytical chemistry

indicates the amount of each substance in a sample

quantitative analysis

Function of Analytical Chemistry except:

Screening

A measurement or observation in which the sample is replaced by a simulated matrix, the conditions otherwise being identical to those under which a sample would be analyzed

Blank

Sometimes called the variability

Precision

Constituent of the sample which is to be studied by quantitative measurements or identified qualitatively

Analyte

Process of determining the proportionality between analyte concentration and a measured quantity

Calibration

The closeness of an experimental measurement or result to the true or accepted value

Accuracy

A large proportion of analytical measurements is subject to interference from other constituents of the sample.

Separation

reveals the identity of the constituents (elements and compounds) in a sample

qualitative analysis

The phenomenon where particles of colloidal dimensions scatter visible radiation

Tyndal effect

Is a process in which a minimum number of atoms, ions, or molecules join together to give a stable solid

Nucleation

is a process in which a substance (gas, liquid, or solid) is held on the surface of a solid.

Adsorption

the analyte is separated from a solution of the sample as a precipitate and is converted to a compound of known composition that can be weighed

Precipitation gravimetry

the analyte is separated from other constituents of a sample by converting it to a gas of known chemicalcomposition

Volatilization gravimetry

the analyte is separated by deposition on an electrode by an electrical current.

Electrogravimetry

is a common source of coprecipitation and is likely to cause significant contamination of precipitates with large specific surface areas.

surface adsorption

is a type of coprecipitation in which a contaminant ion replaces an ion in the lattice of a crystal.

mixed-crystal formation

type of coprecipitation in which a compound is trapped within a pocket formed during rapid crystal growth.

occlusion

it occurs when crystals lie close together during growth

mechanical entrapment

This involves applying electrical energy in the form of spark generated between an electrode and metal sample, whereby the vaporized atoms are brought to a high energy state within a so-called “discharge plasma”

Arc/Spark Atomic Emission Spectrometry

Detectors or ________ measure the absence or presence of the spectrum extracted for each element and the intensity of the spectrum to perform qualitative and quantitative analysis of element.

Photomultipliers

This method uses a sparking process where an electrical discharge is applied to the are being analyzed, causing a small amount of material to be vaporized.

Optical Emission Spectrometry

This method of emission uses laser microprobe, which is applicable in study of small samples or localized areas of larger ones.

Emission by Laser

Arc/Spark Atomic (Optical) Emission Spectrometry is used in quantitative analysis of metals in all types of samples.

True

This can cause a serious error in the results unless the sample is completely burned.

Fractional distillation

Excessive rapid volatilization in the excitation process will introduce a serious error called ______.

Self absorption

This is commonly observed in molecular bands which can cause interference in the excitation process.

Formation of cyanogen radicals

The ratios of readings for the homologous pair are plotted against the amount of analyte in corresponding standard to produce a _______

Both Calibration and Working curve

During sample preparation for non-metals, high purity graphite electrodes are used.

True

GD-AES combines the advantages of ______________ and ____________.

ICP-OES and XRF

Glow discharge optical emission spectrometry (GD-OES) is a widely used tool for fast measurements of _____ profiles.

Depth

It is a technique in which the composition of elements in samples, mostly water-dissolved, can be determined using plasma and a spectrometer.

Inductively Coupled Plasma Optical Emission Spectrometry

It is a technique capable of providing information about the elemental and isotopic composition of samples in situ from a few micrometers down to the sub-micron scale.

Secondary Ion Mass Spectrometry

This technique is an ideal tool to investigate from the surface down to more than 150 microns with a depth resolution that can be as good as 1 nm.

Glow Discharge Atomic Emission Spectrometry

This type of Plasma Emission Source has a distinct advantage; stability with varying sample matrices, a characteristic which is particularly valuable where the solvent contains a high concentration of dissolved solids.

Direct Current Plasma Source

This type of Plasma Emission Source uses an ion source that consists of a torch that is surrounded by a radio frequency generator that ionises argon gas inside the torch to form a high-temperature (up to 10,000 K) plasma that can be used to ionise analytes.

Inductively Coupled Plasma Torch

It is a part of the Plasma Emission Spectrometer which is used in the dispersion of the emitted radiation and in the presentation of the analytical signal.

Both A and B

In Sample Introduction for Plasma Sources, sample solution is pumped by a peristaltic pump at a fixed rate and converted into an aerosol by a _________.

Nebulizer

Plasma Emission Spectrometry is enormous and is most helpful in almost every field where ______analysis is carried out.

Trace Element

An elemental analysis technology capable of detecting most of the periodic table of elements at milligram to nanogram levels per liter.

Inductively Coupled Plasma Mass Spectrometry

Instrument that works on the principle of compound ionization and fragmentation (typically through the bombardment by electrons or selected ions), the physical separation of the charged fragments, and their detection.

Mass Spectrometer

An analytical technique that can be used to measure elements at trace levels in biological fluids.

Inductively Coupled Plasma Mass Spectrometry

Which part of the ICP Mass Spectrometer carries the argon (Ar) that forms the plasma?

ICP torch

An ionised gas, consisting of positively-charged ions and free (unbound) electrons.

Plasma

Principal Zone of Flames where combustion, atomization and thermal excitation occur.

Both Inner Cone and Primary Reaction Zone (A and C)

Flame Emission Spectrometry is a particularly useful technique for the determination of volatile elements with high excitation energies such as the alkali and alkaline earth metals.

False

FES Principle: Emission of electromagnetic radiation in the visible and infrared regions of the spectrum by atoms after electronic excitation in flames.

False

This interference may arise from the close proximity of other emission lines or bands to the analyte line or by overlap with it.

Spectral Interference

This interference occurs because of interaction with ground state atoms of the analyte in the cooler outer fringes of the flame (commonly encountered with easily ionized elements such as alkali metals and alkaline earths) and results in attenuation of the intensity of emission.

Self Absorption

True or False: The principle of AAS is absorption of electromagnetic radiation in the visible and infrared regions of the spectrum by atoms resulting in changes in electronic structure.

False

True or False: One disadvantage of AAS is that it is generally less sensitive than flame emission because the vast majority of atoms produced in the usual propane or air acetylene flame remain in the ground state available for light absorption.

False

True or False: Doppler broadening results from the rapid motion of atoms as they emit or absorb radiation.

True

The radiation emitted as a result of absorption (fluorescence) is measured, often at right angles to avoid measuring the source radiation.

Emission

It is the characteristic of the atoms which have absorbed the primary radiation.

Fluorescent Radiation

Part of AF Spectrometer that collects fluorescence radiation.

Detection System

Generally employed for the routine analysis of specific elements.

Filter based instruments

A wide range of energy transitions (wavelength) and consequently a continuum of X-ray emissions.

White X-Ray

A fluorescent (or secondary) X-ray emitted from a sample when it is excited by a primary X-ray source.

X-Ray Fluorescence

This X-Ray Emission method have a wide application in routine industrial analysis particularly in mineral processing and metallurgy.

X-Ray Fluorescence

A quantitative analysis wherein excitation occurs when an electron residing in a low-energy molecular or atomic orbital is promoted to a higher-energy orbital.

Visible and UV Spectrometry

Unsaturated organic functional groups that absorb in the ultraviolet or visible regions.

chromophore

Saturated groups containing heteroatoms which modify the absorption due to a chromophore.

auxochrome

The shortest wavelength (highest energy) emission, which arises from the transition to the lowestvibrational level in the ground electronic state.

resonance fluorescence

A general term for relaxation in which radiation of a longer wavelength (lower energy) than that originally absorbed is reemitted.

photoluminescence

For ___________, the complexity of the spectrum increases rapidly with the number of atoms N in the molecule.

Polyatomic Molecule

The classical analogy of a vibrating ________ is that of two weights connected by a spring.

Diatomic Molecule

Spectra are usually recorded as liquids, solids or in solution.

Polyatomic Molecule

A __________ behaves rather differently in that the forces of internuclear repulsion arising when the bond is compressed build up rapidly whilst, on stretching, the bond weakens and may finally disrupt.

Diatomic Molecule

Occurs if samples are exposed to the full power of an ultraviolet or visible source.

Photochemical decomposition

Observed only if the chemical shift difference between the coupled groups is large compared to the coupling constant.

First Order Spectrum

Chemical shifts between 13C nuclei in different chemical environments can differ by as much as 200 ppm whereas proton shift differences are seldom more than 10 ppm.

Carbon 13 NMR

Allows only the coupling between 13C nuclei and protons directly bonded to them to be observed.

Off Resonance Decoupling

Consists of irradiating the sample over a wide frequency range covering all the proton resonances in thesample.

Noise Decoupling

Absorption bands arising from adjacent protons are split into multiplet peaks by a mutual interaction of the spins.

Spin spin coupling

In __________, the sample is subjected to a series of single (several microseconds duration), high-power RF pulses of wide frequency range which excite all the nuclei of a particular element (isotope).

Pulsed Fourier Transform NMR

Identifies the specific protons attached to each carbon-13 (1H–13C connectivities)

Heteronuclear Chemical Shift Correlation Spectrometry

Provides proton-proton coupling information (1H– 1H connectivities).

Homonuclear Correlation Spectroscopy

Identifies directly bonded 13C nuclei (13C– 13C connectivities) which allows the carbon skeleton of a compound to be elucidated.

Incredible natural abundance double quantum transfer experiment

Correlated Spectroscopy is also known as

Homonuclear Correlation Spectroscopy

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Reviewer · 87問 · 2年前

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