Novel applications of multichannel spectroscopy in pharmaceutical analysis

Multichannel detectors based on the linear photodiode array, the silicon vidicon tube and charge coupled (or injection) devices are reviewed with reference to their applications in analytical spectroscopy and high-performance liquid chromatography (HPLC). The use of computer-aided techniques, including second derivative spectroscopy and spectral deconvolution methods, for the multichannel spectroscopic analysis of pharmaceuticals is discussed, and applications are reviewed in clinical chemistry, enzyme analysis and studies on aromatic amino acids in proteins. In HPLC, the principles and applications of digital algorithms for validation of peak homogeneity are considered, with reference to spectral suppression, spectral deconvolution, absorbance ratio and the second derivative of the elution profile. The isometric projections of (A, lambda, t) data, and their cartographically equivalent contour plots, are discussed and the impact of multicolour graphics is assessed. The implications of two-dimensional multichannel detectors for detection of luminescence radiation are considered in the context of analytical spectroscopy, and detection in both HPLC and thin-layer chromatography. The potential contribution of charge coupled and charge injection devices as the next generation of multichannel detectors is considered.