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Analytical Chemistry & Spectroscopy

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Analytical Chemistry & Spectroscopy

Analyte

The specific substance whose presence or amount is being determined in an analysis.

mol/L
Analytical Chemistry & Spectroscopy

Analytical Chemistry

The branch of chemistry concerned with identifying substances and determining how much of each is present.

Dimensionless
Analytical Chemistry & Spectroscopy

Atomic Absorption Spectroscopy

A technique that measures the concentration of a metal from the light its free gaseous atoms absorb.

A = εlc ppm
Analytical Chemistry & Spectroscopy

Atomic Emission Spectroscopy

A technique that identifies and quantifies elements from the light their excited atoms emit.

ppm
Analytical Chemistry & Spectroscopy

Back Titration

A technique in which excess reagent is added and the unreacted portion titrated to find how much reacted with the analyte.

n_reacted = n_added − n_remaining mol
Analytical Chemistry & Spectroscopy

Base Peak

The most intense peak in a mass spectrum, assigned an arbitrary relative abundance of 100%.

Dimensionless
Analytical Chemistry & Spectroscopy

Beer–Lambert Law

The relation stating that absorbance is proportional to concentration and to the path length of the sample.

A = ε c l Dimensionless
Analytical Chemistry & Spectroscopy

Blank

A sample containing everything except the analyte, measured to correct for background signal.

Various
Analytical Chemistry & Spectroscopy

Calibration Curve

A plot of instrument response against known analyte concentration, used to determine unknowns.

y = mx + c Various
Analytical Chemistry & Spectroscopy

Carbon-13 NMR

An NMR technique that detects the carbon-13 nucleus to reveal the carbon skeleton of a molecule.

δ 0–220 ppm ppm
Analytical Chemistry & Spectroscopy

Chemical Shift

The position of an NMR signal relative to a reference, expressed in parts per million of the operating frequency.

δ = (ν_sample − ν_ref) × 10⁶ / ν_spectrometer ppm
Analytical Chemistry & Spectroscopy

Chromatography

A family of separation techniques that partition components between a stationary and a mobile phase.

Dimensionless
Analytical Chemistry & Spectroscopy

Chromophore

The part of a molecule responsible for absorbing light at a particular wavelength.

nm
Analytical Chemistry & Spectroscopy

Column Chromatography

A preparative technique in which a mixture is separated by passing it down a vertical column packed with stationary phase.

g
Analytical Chemistry & Spectroscopy

Complexometric Titration

A titration based on the formation of a stable complex between the analyte metal ion and a chelating titrant.

M²⁺ + EDTA⁴⁻ → [M(EDTA)]²⁻ mol/L
Analytical Chemistry & Spectroscopy

Confidence Interval

The range within which the true value of a measured quantity is expected to lie with a stated probability.

μ = x̄ ± ts / √n Various
Analytical Chemistry & Spectroscopy

Electrophoresis

A separation technique in which charged species migrate through a medium under an applied electric field.

v = μE cm/s
Analytical Chemistry & Spectroscopy

Fingerprint Region

The complex lower-frequency part of an infrared spectrum, below about 1500 cm⁻¹, unique to each compound.

400–1500 cm⁻¹ cm⁻¹
Analytical Chemistry & Spectroscopy

Flame Test

A qualitative test in which a sample is heated in a flame and identified by the characteristic colour emitted.

nm
Analytical Chemistry & Spectroscopy

Fragmentation Pattern

The characteristic set of smaller ions produced when a molecular ion breaks apart in a mass spectrometer.

Da
Analytical Chemistry & Spectroscopy

Gas Chromatography

A technique for separating volatile compounds carried by an inert gas through a heated column.

min
Analytical Chemistry & Spectroscopy

Gas Chromatography–Mass Spectrometry

A hybrid technique in which compounds separated by gas chromatography are identified by a mass spectrometer.

Dimensionless
Analytical Chemistry & Spectroscopy

Gravimetric Analysis

Quantitative analysis based on measuring the mass of a product of known composition.

% analyte = (m_precipitate × factor / m_sample) × 100 g
Analytical Chemistry & Spectroscopy

High-Performance Liquid Chromatography

A technique in which a liquid mobile phase is pumped at high pressure through a column of very fine stationary phase.

min