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K W Street

Publications and source records attributed to K W Street.

5 recordsLinked to original sources
PubMed1989

Polycyclic aromatic hydrocarbon solute probes. Part II. Effect of solvent polarity on the fluorescence emission fine structures of coronene derivatives.

The fluorescence properties of coronene (Co), benzo[a]coronene (BCo), naphtho[2,3-a]coronene (NCo), dibenzo[a,j]coronene (DCo), naphtho[1,2,3,4-ghi]perylene, benzo[pqr]naphtho[8,1,2-bcd]perylene and dibenzo[cd,lm]perylene dissolved in solvents of varying polarity are reported. Measurements indicated that the emission intensities of the four coronene derivatives depended on solvent polarity. The Co, BCo and NCo scales have been defined as the ratio of the fluorescence intensities of bands I and III of the vibronic spectra. Band III of dibenzo[a,j]coronene was not clearly identifiable in all the solvents studied, and the DCo scale was therefore defined as the intensity ratio of band I and IV. Emission intensity ratios of the three perylene derivatives remained nearly constant, irrespective of solvent polarity.

Chemical Phenomena↗
PubMed1987

Solubility in binary solvent systems: 8. Estimation of binary alkane plus p-dioxane solvent nonideality from measured anthracene solubilities.

Experimental solubilities are reported for anthracene in binary solvent mixtures containing p-dioxane with n-hexane, cyclohexane, n-heptane, methylcyclohexane, n-octane, cyclooctane, and isooctane at 25 degrees C. Results of these measurements, used in conjunction with the nearly ideal binary solvent (NIBS) model, enabled excess Gibbs free energies, delta GBCfh, of the seven binary solvent mixtures to be estimated. Estimated values for p-dioxane plus cyclohexane, p-dioxane plus n-heptane, and p-dioxane plus methylcyclohexane mixtures are in reasonable agreement with published values based on vapor pressure measurements.

Alkanes↗
PubMed1981

Spectrofluorometric determination of acetylsalicylic acid, salicylamide, and salicyclic acid as an impurity in pharmaceutical preparations.

Spectrofluorometry, either direct or in combination with a separation technique, provides a sensitive and accurate method for the determination of certain extent fluorescent analgesic drugs and the determination of impurities in many combination preparations. A critical examination of the UV spectra of common analgesics and related compounds indicates that the fluorescence inner filter effect should be negligible below 10(-5) M and that selective excitation and emission wavelengths should minimize interference from other fluorescent species. Fluorometric procedures are presented for the determination of salicylamide, acetylsalicylic acid, and salicylic acid, as an impurity, in preparations containing salicylamide, acetylsalicylic acid, acetaminophen, caffeine, and phenacetin as major constituents. Inner filtering is the limiting factor only for the direct and indirect determination of salicylamide and the direct determination of acetylsalicylic acid. Results of fluorometric determinations compare favorably with other reference methods. Salicylic acid is determined in the 10(-7) M concentration range after separation from salicylamide, acetaminophen, and caffeine.

Acetaminophen↗
PubMed1979

p-Aminophenol fluorescence and determination in the presence of acetaminophen.

The spectrophotometric and fluorometric properties of the aminophenols and of several compounds related to p-aminophenol were examined. A direct spectrofluorometric method for p-aminophenol determination at trace levels in methanol was developed and evaluated for the effect of inner filtering by acetaminophen. The method was applied to the determination of p-aminophenol as an impurity in acetaminophen and acetaminophen-containing tablets.

Acetaminophen↗