Analytical Chemistry

Beer's law deals in a similar way with the concentration C of an absorbing species and leads to the relation Combining the two g ...

mize errors in setting the instrument at the chosen wavelength. This also minimizes apparent deviations from Beer's law for inci ...

(b) Dichromate and chromate ions in aqueous solutions interconvert to a degree which is pH dependent: Unless standards are prepa ...

instruments. Another limitation is the inability to determine a true absorption curve. For these reasons, it is often desirable ...

Figure 9.4 Variation of relative error with absorbance. Constant instrumental error 1%. Curve A: photovoltaic detector. Curve B: ...

Applications A most widely used technique for quantitative trace analysis. Used as an adjunct to other spectrometric techniques ...

two vibrational levels in the ground and first excited electronic states respectively. At room temperature all molecules will be ...

(antibonding) orbitals are shown in Figure 9.7(a). The relative energies of these orbitals and that of a non-bonding orbital n, ...

Table 9.2 *Absorption characteristics of some typical chromophores * See footnote to Table 9.3 Conjugation Effects Absorption ba ...

conjugation, as in the carotenes (ten or more double bonds), the compound may appear orange, red, purple, or even black. Benzene ...

increases in the energies of π and π orbitals, the π being raised by more than the π, but leaves the energy of the non-bonding o ...

affected by the presence of a metal. (3) Charge-transfer transitions, involving the transfer of an electron between two orbitals ...

The last two types give rise to many strongly coloured complexes suitable for trace analysis. Bands due to d–d transitions are r ...

dianion at 650 nm is shifted to 530 nm by interaction with Mg2+. Similarly, a series of coloured complexes are formed between Cu ...

Quantitative Analysis – Absorptiometry The use of visible and UV spectrometry for quantitative analysis by comparing the absorba ...

Figure 9.10 Ringbom calibration curves. Photometric Titrations The change in absorbance during a titration in which one of the r ...

sipated as heat in 10–^11 – 10 –^15 s by collisions between solute and solvent molecules, may be followed by the slower (10–^9 t ...

A fluorescence emission spectrum arises from transitions between the lowest vibrational level of the first excited electronic st ...

fused aromatic systems, cf. biphenyl and fluorene (Figure 9.11(b)). Structures containing heteroatoms or which are ionized may u ...

There is a linear relation between the concentration, C, of a fluorescent analyte and the intensity of emission, IF, given by th ...