Stanley M. Klainer

Remote Detection of Organochlorides With a Fiber Optic Based Sensor

ABSTRACT Optical fibers, analytical chemistry, and fluorescence spectroscopy have been integrated to form the new technology of remote fiber fluorimetry. Among the many potential applications of this technology is the measurement of volatile organochlorides in ground water and in the vadose zone. The key to this application was the development of a fiber optic chemical sensor (FOCS) with sub-ppm sensitivity for, at least, chloroform and trichlorethylene (TCE). We present here the concept and instrumentation of remote fiber fluorimetry, the design and laboratory evaluation of an organochloride FOCS, and preliminary field results of the application of the FOCS to contaminated well water.

Clinical measurements using fiber optics and optrodes

Fiber optics, optrodes, and fluorescence spectroscopy have been combined to form the new technology of remote fiber fluorimetry (RFF). Both in-vivo and in-vitro clinical measurements can be made by using this technique. The optrode, a fiber termination with preselected chemical or physical properties, is attached to the distal end of the optical fiber so that specific, in-situ measurements can be made. RFF systems for pH, blood pressure, oxygen, and carbon dioxide are being completed, and other optrodes are in the development stages.

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

ABSTRACT A dedicated portable fluorimeter, 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 μm 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.

Studies of Gaseous Flame Combustion Products by Raman Spectroscopy

Combustion products from various hydrocarbon-oxygen flames have been examined in the laboratory using the techniques of laser Raman spectroscopy and phase-sensitive detection. Instrumentation, techniques, and spectral results are described.

An Efficient Intracavity Laser Raman Spectrometer

The design of an optimized intracavity laser Raman spectrometer is described, and representative Raman scattering data are presented. An intracavity laser power of 160 W was attained with an argon ion laser whose normal output power was 1 W.

Development Of A Fiber Optic Chemical Sensor For The Monitoring Of Trichloroethylene In Drinking Water

A fiber optic chemical sensor (FOCS) has been developed for the monitoring of trichloroethylene in drinking water. The sensor is based upon refractive index changes, where the amount of light refracted varies as the analyte interacts with the coated surface. Response is specific for TCE, reversible, and can be used for monitoring TCE in the vapor or aqueous phase.

Field-hardened optical waveguide hybrid integrated-circuit multisensor chemical probe and its chemistry

A single probe containing three hybrid integrated-circuit, optical waveguide, chemical-biochemical sensors (chip sensors) has been developed. Each chip sensor contains two hybrid waveguides -- one for sensing and one for reference. The sense waveguide is coated with a species-specific or group-specific chemistry or biochemistry. The reference waveguide is coated with a version of the sense chemistry or biochemistry, which is not sensitive to the analyte. The integrated structure is encapsulated and contains a single fixed light source, two detectors (reference and sense), and an optical train. The design is amenable to fluorescence, absorption, and refraction measurements. The three chip sensors are individually mounted in a probe that contains all of the electronics and computing capability necessary to collect and process the output information from each chip sensor. Only the surface of the individual chips are exposed to the target analytes. The probe is rugged, intrinsically safe, and can operate under 75 m (250 ft) of water.

In-situ monitoring for hydrocarbons using fiber optic chemical sensors

The use of FOCS for environmental applications, namely, for monitoring spills of HC or leaking underground HC storage tanks, is discussed. The current FOCS design comes in two configurations: the field unit, permanently installed at one or more monitoring sites, and connected to a central monitoring station, and the hand-held unit, designed for rapid on-site evaluation. The sensors performance in HC vapor at 100 percent relative humidity and at 20 C, and at the vapor-water interface is illustrated.

A Fiber Optic Chemical Sensor For Carbon Dioxide Dissolved In Sea Water

A fluorescence based fiber optic chemical sensor has been developed to measure the concentration of dissolved carbon dioxide in sea water. The sensor configuration involves a single strand of step index multimode silica fiber, one end of which is terminated with a conical ferrule connector while the other end is incorporated with a special reservoir cell. This special cell contains a CO2 permeable membrane at the tip. An aqueous solution of 8-hydroxy-1,3,6- pyrenetrisulfonic acid-trisodium salt has been employed as the sensing reagent. CO2 dissolved in water permeates through the membrane into the sensing solution and alters its pH causing modulation in the emission intensity of the dye. Linear response is observed for this sensor over 0-600 ppm range. Measurements are done with a custom made filter fluorimeter.

Self-contained handheld optical waveguide chemical sensor system

A self-contained, hand-held, optical waveguide, chemical detection system has been built to detect and quantify gases and vapors. The system uses a hybrid integrated circuit (IC) containing optical waveguides coated with sensing chemistry as the optical platform. The IC with sensing chemistry is available commercially under the name Sensor-on-a-Chip. This IC is mounted in a small, uniquely designed sample chamber where the measured analyte is identified by the sensing chemistry and biochemistry. Continuous or stop-flow sampling is possible. Sensitivities in the low parts-per-million have been attained for hydrocarbons and alcohol. Analyte coverage is only limited by the sensing chemistries and biochemistries that are available.