Organic Constituents

Abstract : A lot of organic constituents in solution absorb in the UV-visible region. Dyes and coloured compounds absorb in the visible range, and colorimetry, using reagents with interesting optical properties, has been used for decades in analytical chemistry. However, numerous organic molecules with unsaturated bounds absorb in UV, as for example compounds with a conjugated structure (e.g., aromatic rings). The UV spectra of organic constituents can be exploited for their determination, if their concentration is detectable. In case of trace analysis of pesticides or pharmaceuticals, an extraction step is necessary before UV detection. Moreover, the estimation of aggregated organic constituents (phenols, polycyclic aromatic hydrocarbons (PAHs), surfactants) is possible. For some nonabsorbing compounds, a derivatization with a UV response can be used for their analysis, and for some other a simple photo-oxidation step can reveal their presence. © 2017 Elsevier B.V. All rights reserved.