Encyclopedia of Environmental Science and Engineering, Volume I and II

INSTRUMENTATION: WATER AND WASTEWATER ANALYSIS 549

by a substance is resolved into its component wavelengths

indicating its intensity and presented as a spectrum. In

this category absorption, emission, and photoluminescence

(fluorescence and phosphorescence) spectroscopy using

x-ray, ultraviolet–visible (uv–vis), and ir radiation, and the

measurement of turbidity, or suspended matter by neph-

elometry and turbidimetry, are included. However, today in

a broader sense, spectroscopy includes the following: reso-

lution of electrons of many energies by uv and x-ray photo-

electron, Auger etc. spectroscopy; sound waves by acoustic

spectroscopy; ions by mass number by mass spectroscopy;

and absorption of radiowaves by atoms and electrons exposed

to a magnetic field in nuclear magnetic resonance and

electron spin resonance spectroscopy. The phenomena of

absorption, emission, photoluminescence (fluorescence and

phosphorescence), and scattering are the bases of spectro-

scopic instruments.

b. Spectroscopic instruments

Spectroscopic instrumentation is differentiated with

respect to the wavelength range of the instrument, that is

x-ray, uv, visible, and ir and type of instrument, i.e. absorp-

tion, emission, photoluminescence (fluorescence and phos-

phorescence), and turbidity. The energy sources, sample

cells, wavelength selection devices (gratings, prisms, filters,

crystals) and sensors may differ for these various instru-

ments. These parts are listed in Figure 3 for the wavelength

regions of from 100 to 40,000 nm (nanometer, 10^ ^9 meters).

X-ray and non-optical spectroscopic instruments are not

included.

TABLE 4

Bases for instrumental methods

Energy interaction Process Instrumental method

EMR, range Absorption of emr x-ray, uv/vis atomic & ir spectrophotometry

Emr/magnetic field Absorption of emr in a magnetic field NMR spectroscopy

e, ions, or electric field Ion formation/seperation in electric or

magnetic field

Mass spectroscopy

Electricity (arc, spark), heat (flame,

plasma)

Emission of emr x-ray, uv/vis, flame emission spectroscopy

Emr, x-ray Emission of electrons x-ray photoelectron spectroscopy (XPS or

ESCA)

Emr, uv Emission of electrons UV photoelectron spectroscopy (UPS)

x-ray or e Emission of electrons Auger spectroscopy

Emr, uv/vis Emission of acoustic energy Photoacoustic spectroscopy

None Emission via radioactive decay Radiochemical methods

Emr, range Fluorescence & phosphorescence of emr x-ray uv/vis^1 , & atomic fluorescence

spectroscopy

Emr, vis Scattering of emr by particles Nephelometry, turbidimetry

Emr, vis Scattering of emr by molecules Raman spectroscopy

Emr, x-ray Diffraction x-ray diffraction

Emr, vis Refraction (bending of light beam) Refractometry

Emr, uv/vis Rotation of plane-polarised light Polarimetry

Emr, uv/vis Rotation as a function of wavelength Optical rotatory dispersion

Emr, uv/vis Rotation using circularly polarized light Circular dichroism

Electricity current measurement Amperometry, coulometry, polarography,

voltammetry

Electricity pass current/weigh-plated material Electrogravimetry

Electricity potential measurement Chronopotentiometry, potentiometry

Electricity resistance/conductance measurement Conductometry

Heat weight loss vs increasing temperature

differential temperature vs increasing

temperature heat flow to sample vs

increasing temperature. Temperature vs

volume of reagent

Thermogravimetric analysis. Differential thermal

analysis. Differential scanning calorimetry.

Enthalpimetric methods

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