Search results for "Bromocresol green"
showing 4 items of 4 documents
Extractive Spectrophotometric Determination of Ondansetron by Ion-Pair Formation with Bromocresol Green
1996
Abstract An empirical spectrophotometric procedure for the determination of the antiemetic ondansetron is carried out. The method is based on the formation of a 1:1 ion pair with bromocresol green in the pH range over 3.2 – 4.4, extraction into chloroform layer and spectrophotometric measurement at 420.8 nm. The calibration graph is linear over the range 0.1 – 20 μg ml−1 ondansetron, with a relative standard deviation of 2.7%; the influence of foreign substances is also studied. The method is applied to ondansetron determination in human urine.
Medium for Screening Leuconostoc oenos Strains Defective in Malolactic Fermentation
1989
A new sensitive medium was developed to screen and isolate mutagenic Leuconostoc oenos strains defective in malolactic fermentation. The essential components of the medium included fructose (22 mM), l -malic acid (74.6 mM), bromocresol green (as pH indicator), and cellulose powder. The wild-type colonies turned blue, but defective malolactic colonies gave an acid reaction and remained yellow-green.
Spectrophotometric determination of chlorhexidine with bromocresol green by flow-injection and manual methods
1986
Abstract A spectrophotometric study of the chlorhexidine/bromocresol green/Triton X-100 system is reported; at pH 5.3, both 2:1 and 1:1 bromocresol green/chlorhexidine complexes are formed. In the manual spectrophotometric method, Beer's law is obeyed for chlorhexidine concentrations of 2.9–32.2 μg ml −1 (r.s.d. 0.4–1.3%); the molar absorptivity is 12 500 l mol −1 cm −1 . In the flow-injection method, the calibration graph is linear for the chlorhexidine range 23.0–83.9 μg ml −1 (r.s.d. 0.8%); the injection is ca. 60 h −1 . Benzocaine, acetylsalicylic acid, ascorbic acid and sucrose are tolerated at 10 −2 −10 −3 M levels. Hibitane 5% was analyzed successfully.
Flow injection spectrophotometric determination of boron in ceramic materials.
1998
Abstract A flow injection spectrophotometric method for the determination of boron in ceramic materials is described. The method is based on spectrophotometric measurement of the decrease in the pH produced by the reaction between boric acid and mannitol in the presence of an acid-base indicator. A bichannel FI (flow injection) manifold in which the sample solutions were injected into deionized water (at pH 5.4) and the stream was later merged with the reagent stream (a mannitol solution containing 1×10 −4 mol l −1 bromocresol green at pH 5.4), was used. Transient signals were monitored at 616 nm. A theoretical model which describes the dependence between the absorbance values and boric aci…