“…A number of reviews dealing with spectrophotometric techniques have been published including methods of modulation spectroscopy (296), the Fourier transform technique (7), simultaneous determinations in multicomponent systems (532), differential spectrometry (157, 312), and superhighsensitivity methods (197) and the use of optical fibers for remote sensing (44). The use of photoacoustic spectrometry continues to grow as evidenced by the large number of reviews of this technique.…”