Sensors based on integrated retention and photometric detection

2 Sensors based on integrated retention and photometric detection 

The determination of formaldehyde, a substance of great interest on account of its toxicity and high significance to the resin, fertilizer and explosive manufacturing industries, among others, entails the use of rapid, convenient, safe methods. One sensor developed for this purpose uses the manifold shown in Fig. 4.6 to handle the reagents involved, viz. / -rosaniline (PRA) and sulphite. The instability of sulphite ion calls for on-line mixing with PRA dissolved in 0.4 M HCl prior to injection of the sample. After the 

Ever since Albrecht and Creighton [85], and Jenmarie and van Duyne [86], observed that the Raman cross-section for pyridine absorbed on a roughened silver electrode was larger than that in solution by six orders of magnitude, surface enhanced Raman spectroscopy (SERS) has steadily gained ground in analytical instrumentation. The sensitivity of this technique 

---