Analytical Chemistry & Spectroscopy — 60 Terms Defined

Analyte Analytical Chemistry & Spectroscopy mol/L The specific substance whose presence or amount is being determined in an analysis.

Analytical Chemistry Analytical Chemistry & Spectroscopy Dimensionless The branch of chemistry concerned with identifying substances and determining how much of each is present.

Atomic Absorption Spectroscopy Analytical Chemistry & Spectroscopy ppm A technique that measures the concentration of a metal from the light its free gaseous atoms absorb. A = εlc

Atomic Emission Spectroscopy Analytical Chemistry & Spectroscopy ppm A technique that identifies and quantifies elements from the light their excited atoms emit.

Back Titration Analytical Chemistry & Spectroscopy mol 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

Base Peak Analytical Chemistry & Spectroscopy Dimensionless The most intense peak in a mass spectrum, assigned an arbitrary relative abundance of 100%.

Beer–Lambert Law Analytical Chemistry & Spectroscopy Dimensionless The relation stating that absorbance is proportional to concentration and to the path length of the sample. A = ε c l

Blank Analytical Chemistry & Spectroscopy Various A sample containing everything except the analyte, measured to correct for background signal.

Calibration Curve Analytical Chemistry & Spectroscopy Various A plot of instrument response against known analyte concentration, used to determine unknowns. y = mx + c

Carbon-13 NMR Analytical Chemistry & Spectroscopy ppm An NMR technique that detects the carbon-13 nucleus to reveal the carbon skeleton of a molecule. δ 0–220 ppm

Chemical Shift Analytical Chemistry & Spectroscopy ppm 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

Chromatography Analytical Chemistry & Spectroscopy Dimensionless A family of separation techniques that partition components between a stationary and a mobile phase.

Chromophore Analytical Chemistry & Spectroscopy nm The part of a molecule responsible for absorbing light at a particular wavelength.

Column Chromatography Analytical Chemistry & Spectroscopy g A preparative technique in which a mixture is separated by passing it down a vertical column packed with stationary phase.

Complexometric Titration Analytical Chemistry & Spectroscopy mol/L A titration based on the formation of a stable complex between the analyte metal ion and a chelating titrant. M²⁺ + EDTA⁴⁻ → [M(EDTA)]²⁻

Confidence Interval Analytical Chemistry & Spectroscopy Various The range within which the true value of a measured quantity is expected to lie with a stated probability. μ = x̄ ± ts / √n

Electrophoresis Analytical Chemistry & Spectroscopy cm/s A separation technique in which charged species migrate through a medium under an applied electric field. v = μE

Fingerprint Region Analytical Chemistry & Spectroscopy cm⁻¹ The complex lower-frequency part of an infrared spectrum, below about 1500 cm⁻¹, unique to each compound. 400–1500 cm⁻¹

Flame Test Analytical Chemistry & Spectroscopy nm A qualitative test in which a sample is heated in a flame and identified by the characteristic colour emitted.

Fragmentation Pattern Analytical Chemistry & Spectroscopy Da The characteristic set of smaller ions produced when a molecular ion breaks apart in a mass spectrometer.

Gas Chromatography Analytical Chemistry & Spectroscopy min A technique for separating volatile compounds carried by an inert gas through a heated column.

Gas Chromatography–Mass Spectrometry Analytical Chemistry & Spectroscopy Dimensionless A hybrid technique in which compounds separated by gas chromatography are identified by a mass spectrometer.

Gravimetric Analysis Analytical Chemistry & Spectroscopy g Quantitative analysis based on measuring the mass of a product of known composition. % analyte = (m_precipitate × factor / m_sample) × 100

High-Performance Liquid Chromatography Analytical Chemistry & Spectroscopy min A technique in which a liquid mobile phase is pumped at high pressure through a column of very fine stationary phase.