Quantitative Analysis

Historically, chemical analysis of water was achieved by titration methods. It is, practically, impossible to use these on water containing a pollutant at a low con­centration due to the need to collect a very large volume of water that can be con­centrated to permit a weighable amount of chemical to be obtained at the end of the procedure. Also, such procedures are very time-consuming and operator sensi­tive. Therefore, modern analysis is based on electrical, atomic and spectrographic techniques.

The most common analytical techniques suitable for determination of the pres­ence of selected pollutants are synthesised in Table 7.3.

Table 7.3 Analytical techniques suitable for determination of the presence of selected pollutants

Technique

Detection limit level

Basic

Common

Platinum

Organic

cations*

heavy

group

compounds

metals)

elementsf

(e. g. PAH and their derivates, HCB, PCB)

Gas Chromatography

Depends on sample

X

(GC)

preparation and detector used

Liquid Chromatography

Depends on sample

X

(LC)

preparation and detector used

Atomic Absorption

mg. l-1 or pg. l-1

X

X

Spectrometry (AAS)

(ppm or ppb)

Inductively Coupled

pg. l-1 or ng. l-1

X

X

Plasma (ICP)

(ppb or ppt)

Molecule Absorption

mg. l-1 or pg. l-1

X

X

spectrometry in the UV — VIS

(ppm or ppb)

environment

(UV-VIS) Ion Exchange

Depends on sample

X

X

Chromatography

preparation and

(IEC)

detector used

* = include sodium, potassium, calcium, barium and magnesium.

X = include iron, copper, zinc, cadmium, lead, chromium, nickel, cobalt and vanadium. f = here include rhodium, palladium, iridium and platinum. PAH = polyaromatic hydrocarbons, HCB = hexachlorobenzene, PCB = polychlorinated biphenyls. ppm = parts per million (10-6). ppb = parts per billion (10-9). ppt = parts per trillion (10-12).

Updated: 19 ноября, 2015 — 9:25 дп