Remote Detection of Organochlorides With a Fiber Optic Based Sensor

In situ detection of organic molecules: Optrodes for TCE (trichloroethylene) and CHCl sub 3

“…Consequently, path b of Scheme I represents an important competing reaction sequence that leads to the production of unwanted products and reduced yields of 2. This sequence is similar to the Fujiwara reaction, in which CHCl3 reacts with pyridine in a solution of alkaline hydroxide.11 The major products of the Fujiwara reaction are aldehydic imines and amidines derived from cleavage of the Nalkylated pyridine ring.12 This reaction is performed under conditions consistent with the production of :CC12 and is inhibited with common carbene traps such as methanol.13 Although the Fujiwara reaction is generally executed in single-phase media, other reactions have reportedly been performed under conditions of basic PTC with CHClJ and substituted pyridines that invoke mechanisms involving the reaction of :CC12 at the pyridyl ring nitrogen.14 Moreover, various other carbenes (e.g., : C (CN) 2 and : C (C02Et) 2) are known to form stable ylides with pyridine and azanaphthalenes,6,15 and recently it has been reported that ylide intermediates are formed by the reaction of pyridine with phenylchlorocarbene ,16 In the case of 2-AMP, an analogous reaction is proposed in which the pyridyl ring nitrogen competes with the aminomethyl group for :CC12 to generate a -cc12-pyridinium species (8).…”

Performance specifications for technology development: Application for characterization of volatile organic compounds in the environment

“…The combination of a FOCS for chloroform (based on fluorescence detection of a chloroform reaction product) and an associated field-portable fiber-optic fluorometer has been described in the literature (Milanovich et al 1986b). The results of a preliminary field demonstration of a first-generation chloroform FOCS that uses a high-powered laser and photoncounting techniques have been published (Milanovich et al 1986a). The portable fiber fluorometer system and the gas-phase chloroform FOCS have been used to characterize a chloroform-contaminated water-well field (Herron et al 1989).…”

Chemical sensor and field screening technology development: Downhole photoionization detection of volatile organic compounds. Topical report, March 1, 1995--March 31, 1996

“…One approach uses refractive index attenuation on a coated optical fibers (Le Goullon andGoswami 1990, Oxenford et al 1989). Another probe uses a chemical reaction in a basic medium to form a color in the presence of trichloroethylene (Milanovich et al 1986). A radio frequency-induced helium plasma optical emission spectrometer has been designed to measure some volatile chlorinated compounds (Olsen et al 1989).…”