Search results for "Cresol"
showing 10 items of 30 documents
Interpretive optimisation strategy applied to the isocratic separation of phenols by reversed-phase liquid chromatography with acetonitrile–water and…
2000
An optimisation protocol is presented for the resolution of complex mixtures in isocratic RPLC with binary mobile phases of organic solvent and water, which is based on the prediction of peak position and shape of the individual compounds. A good description of the retention was achieved through the application of statistical weights to the widely used linear or quadratic relationships between the logarithm of the retention factor (log k) and the organic solvent concentration in the mobile phase. The maximisation of the product of peak purities for each compound is shown as a competitive resolution strategy versus the worst value of a selectivity parameter. Peak purities allow one to associ…
Multicentre evaluation of in vitro contracture testing with bolus administration of 4-chloro-m-cresol for diagnosis of malignant hyperthermia suscept…
2003
Background and objective The in vitro contracture test with halothane and caffeine is the gold standard for the diagnosis of susceptibility to malignant hyperthermia (MH). However, the sensitivity of the in vitro contracture test is between 97 and 99% and its specificity is 78-94% with the consequence that false-negative as well as false-positive test results are possible. 4-Chloro-m-cresol is potentially a more specific test drug for the in vitro contracture test than halothane or caffeine. This multicentre study was designed to investigate whether an in vitro contracture test with bolus administration of 4-chloro-m-cresol can improve the accuracy of the diagnosis of susceptibility to MH. …
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.
Experimental conditions for respiration and growth studies of F0 and F1 larval and juvenile European seabass Dicentrarchus labrax
2022
Water parameters in the 2 years before spawning of F0 (08.02.2016-06.03.2018) and during larval and juvenile phase of F1: Larval period until 17.05.2018 (48 dph, 900 dd) and 01.06.2018 (63 dph, ~900 dd) for warm and cold life condition respectively, for the juveniles until 28.09.2018 (180 dph, ~4000 dd) and 12.02.2019 (319 dph, ~5100 dd) for warm and cold conditioned fish respectively. Means ± s.e. over all replicate tanks per condition. Temperature (Temp.), pH (free scale), salinity, oxygen and total alkalinity (TA) were measured weekly in F1 and monthly in F0; sea water (SW) measurements were conducted in 2017 and 2018. Water parameters during larval and early juvenile phase of F0: Larval…
Comparison of viability assays for Cryptosporidium parvum oocysts after disinfection.
2003
Abstract In order to test various viability assays for Cryptosporidium parvum oocysts were used to infect HCT-8 cells in vitro or baby mice. Infected cells were either stained with fluorescent anti- Cryptosporidium -antibody or lysed and subjected to C. parvum- specific PCR after 48 h. Titrations with infective oocysts were performed and compared to oocysts disinfected with Neopredisan © for 2 h at varying concentrations. Caecal smears and histological sections from infected animals were examined in parallel. The number of foci of parasite development in vitro after immunofluorescent staining correlated well with the infection dose. PCR was less quantifiable and the results were not always …
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.
Thin-layer chromatography of 2-methyl-4-chlorophenoxyacetic acid and its soil metabolites
1980
Abstract The thin-layer chromatography of 2-methyl-4-chlorophenoxyacetic acid, 4-chloro- o -cresol and 3-methyl-5-chlorocatechol and their pentafluorobenzyl derivatives has been studied on silica gel as adsorbent with 19 solvent systems. The best separation of the individual components occurred with toluene-benzene-acetic acid (2:2:1). Chloroform-diethyl ether-toluene (1:1:1) was suitable for the group separation of the pentafluorobenzyl derivatives.
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.
H-point standard additions method for resolution of overlapped chromatographic peaks with a conventional fluorescence detector. Determination of phen…
1996
The H-Point Standard Additions Method (HPSAM) is proposed in order to resolve overlapping peaks in liquid chromatography by using a conventional fluorescence detector. The method uses as analytical signals the heights or the areas obtained at two previously selected emission wavelengths, and good results are obtained for highly overlapping peaks with highly overlapping fluorescence spectra. The principal benefits of the method are the ease of finding the required wavelengths, its insensitivity to changes in the retention time of the peak from one injection to another, and the possibility of using it in highly or only partially overlapping peaks. We have applied the method to the determinati…
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…