Remote Detection of Organochlorides With a Fiber Optic Based Sensor II. a Dedicated Portable Fluorimeter

Abstract

A dedicated portable fluorineter, for use with fiber optic chemical sensors (FOCS) has been designed, constructed, tested, and calibrated. This represents a major advance in the development of a FOCS system suitable for in-field use. The portable fluorimeter uses an incandescent lamp, instead of a laser, for FOCS excitation and a photodiode, in place of a photomultiplier tube for detecting the fluorescence signal. It uses an optical system which is internally connected to a unitized optical block by 600 pm core optical fibers, to minimize alignment problems and increase overall system ruggedness. The system noise is less than .1.5 mV and the long-term drift is less than ±2 mV/hour. Measurements of organochloride were made at concentrations as low as 80 parts-per-billion with a signal to noise ratio of 40:1.

Polymer immobilized enzyme optrodes for the detection of penicillin

“…In view of the solvent-dependent liquid junction potential problem, there has been considerable interest in finding solvent independent redox couples that can be used as reference redox systems in both organic and aqueous solvents (5)(6)(7)(8)(9)(10)(11)(12)(13). Unfortunately, the standard redox potential of a given redox system in solution invariably depends to some degree on the nature of the solvent in which it is measured (14).…”

“…All measurements for the polyacrylamide fluorescein penicillin optrode were performed with a portable fiber-optic fluorometer built by Douglas Instruments (Palo Alto, CA). This instrument was described in detail elsewhere (12). Its features include tungsten-halogen lamp illumination chopped at 30 Hz by a tuning fork and filtered with a narrow band-pass filter centered at the peak of the fluorescein absorption maximum.…”

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

“…Studies have shown that groundwater from 33% of the hazardous waste sites in the United States is contaminated with chloroform (Plumb and Pitchford 1985;Plumb 1987). 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).…”

Development of a fibre optic luminescence lifetime spectrometer

“…The aim of the project was to develop a fibre optic luminescence lifetime spectrometer, that is capable of measuring sub-nanosecond lifetimes. This is because of the advantages of using optical fibres for remote detection (Malstrom and Hirschfield 1983;Newby et al 1984;Milanovich et al 1986) as well as for delivery of the excitation light to a small volume sample or to a specific site (Minami et al 1986). Optrodes (OPTical electRODES) would be preferable to electrically based sensors in many areas, especially in biomedical applications (Peterson and Vurek 1984;Tromberg 1984Tromberg , 1987Coburn 1985;Wolfbeis 1985).…”