Edward J. Poziomek

Use of Anisotropic Materials as Chemical Detectors

Abstract The visual detection between crossed polarizers, of organic vapors on various liquid crystal films is reported. Non-selective detection is achieved in the ppm range. However, opportunities exist for bettering selectivity and sensitivity as illustrated with a combined polymer-liquid crystal detection system for amines. Also described is the detection of liquid droplets by utilizing changes in the birefringence of polycarbonate membrane filters.

Transparency Characteristics of Several Cholesteryl Esters

Abstract Transparency characteristics are reported for cholesteryl myristate, decanoate, and nonanoate from the solid to the isotropic liquid phases. The procedure involves heating a sample between calcium fluoride plates in a brass holder in a Cary 14 spectrophotometer. Changes in transmittance at fixed wavelengths (3000, 4000, 5000, 7000, and 25,000 A) were recorded continuously as the temperature was allowed to change slowly. The transparency characteristics of cholesteryl nonanoate while being cooled from the liquid phase are also described. All transitions which occur are observed. By comparison with other techniques this method compares very favorably with regard to the detection of transitions and dichroic scattering. The shapes of the transparency curves vary markedly between compounds; the degree of light scattering varies as a function of the incident light wavelength. However, the temperature ranges over which the transitions occur for a particular compound are reproducible irrespective of the ...

Design of olfactory detection reactions based on isocyanide formation

Information is provided on the design of olfactory detection reactions based on isocyanide formation. Potential detection, warning or identification schemes can be designed by scanning a listing of reagents or classes of compounds to be detected and then tabulating the reagent combinations which will produce isocyanides.

A Technique of Measuring the Transparency of Materials as a Function of Temperature

Abstract : A simple technique has been developed to measure the transparency of materials at any specific wavelength (ultraviolet to near infrared) versus temperature. The procedure involves heating a sample between calcium fluoride plates in a brass holder placed in a Cary-14 spectrophotometer. Changes in transmittance at a fixed wavelength are recorded continuously as the temperature is allowed to change slowly. As an illustration of the procedure, the transmission properties of the nematic liquid crystal butyl p-(p- ethoxyphenoxycarbonyl)-phenyl carbonate in its various states are described. For comparative purposes a description of the transmitance of phenyl benzoate (which does not possess a mesophase) is also included.

A multicyclic catalytic scheme for the vapor detection of organophosphorus compounds

Abstract A multicyclic catalytic scheme for the vapor detection of the organophosphorus compound isopropyl methylphosphonofluoridate, GB, is described. A detector tube containing silica gel impregnated with 1-phenyl-1,2,3-butanetrione 2-oxime, o-dinitrobenzene, and p-nitrobenzaldehyde detected 0.12 and 0.3 μg of GB in 5 and 3 minutes, respectively.

Detection of amines by using the depolymerization of poly(chloroaldehydes)

Abstract A detector tube is described in which amine vapors cause decomposition of a chloral-dichloroacetaldehyde copolymer. Detection signal is based on the dissolution of the dye pinacyanole by the liberated chloroacetaldehyde monomers. Of the 77 amines tested, ammonia, allylamine, n -butylamine, isobutylamine, sec -butylamine, cyclohexylamine, diethylamine, dibutylamine, dipropylamine, and piperidine gave strongest tests. The limit of detection of diethylamine is approximately 2 μg. The sensitivity is increased about one order of magnitude if solution techniques are employed. Interferences appear to be few since 71 compounds representing 21 classes of compounds did not give a test.

MICROCHEMICAL DETECTION OF ELECTROPHILIC CHEMICALS

Abstract N-Alkylformamides are shown to be useful in the detection of electrophiles by the formation of isocyanides. Down to 0.2 μ of tosyl chloride is detectable by combining the formamide dehydra...

Qualitative detection methods based on the liberation of ammonia from hexamminecobalt(III) perchlorate

Abstract A number of compounds were screened for their general ability to liberate ammonia from hexamminecobalt(III) perchlorate in aqueous buffer and dimethyl sulfoxide. The ammonia was detected by a strip of moistened pH paper hung above the solution in a closed vial. Various compounds were detected, e.g., sodium iodide, phenols, hydroquinone, sodium sulfite, trypsin, Malathion, DDT, and several amines. It is concluded that the liberation of ammonia in substitution and reduction reactions of hexamminecobalt(III) perchlorate can be used for the qualitative detection of a number of nucleophiles and reducing agents. Specificity can be achieved by varying the reaction solvent. The primary application is in detection of relatively nonvolatile substances by converting them to readily detectable ammonia vapor.