Resorcinol, detection

Proprietary dual wavelength detection for ninhydrin-detectable amino acids and 2-pyridyl resorcinol-detectable transition metals. 

HPLC method with amperometric detection was applied for detenuination of phenols in sea sediment and some dmg preparation. Peaks of phenol, guaiacol, cresols, hydroquinon and resorcinol were identified on chromatogram of birch tai. The HPLC method with electrochemical detectors was used for detenuination of some drug prepai ation of aminophenol derivate. So p-acetaminophenol (paracetamol) was determined in some drug. 

Saccharin and the three diphenols, pyrocatechol, resorcinol and hydroquinone, react only weakly or not at all. The same is true of picric acid. On the other hand, cyclohexanesulfamic acid and bis-(2-ethylhexyl)-phosphoric acid are readily detected [1]. 

A dipping solution consisting of 0.2% fast blue salt B in hydrochloric acid (c = 0.5 mol/1, immersion time 30 s) has been reported for the detection of resorcinol homologues [1]. 

The phenols pyrocatechol, resorcinol and hydroquinone can be detected with all chloramine T reagents. The detection sensitivity is about the same with chloramine T - sodium hydroxide and chloramine T - trichloroacetic acid. In all cases the detection limits are ca. 75 ng substance per chromatogram zone after the plate has been subsequently dipped in a paraffin oil solution. Somewhat less favorable detection limits of 150 to 200 ng substance per chromatogram zone are obtained after treatment with chloramine T - hydrochloric acid and chloramine T - sulfuric acid. 

Irreversible reaction of [18] iodine with acetylsalicylic acid, aethaverine, amidopyrine, ascorbic acid, benzo-caine, quinine, dihydrocodeine, fluorescein, glycine, hydrocortisone acetate, isoni-azid, metamizole, papaverine, paracetamol, phenacetin, phenol-phthalein, piperazine, resorcinol, salicylic acid, salicylamide, sulfaguanidine, thymol, triethanolamine, tris buffer detection by reaction chromatography... 

Figure 4.10 Typical routine column test chromatogram for a 30 cm X 4.6 mm I. D. column pacXed with an octadecylsiloxane bonded silica packing of lO micrometers particle diameter. The test mixture consisted of resorcinol (0.55 mg/ml), acetophenone (0.025 mg/ml), naphthalene (0.20 mg/ml) and anthracene (0.01 mg/ml) in acetonitrile, 10 microliters injected. The separation was performed isocratically at 23 C with acetonitrile-water (55 45) as the mobile phase at a flow rate of 1.5 ml/min. Detection was by UV at 254 nm (0.1 AUFS).

As the majority of stabilisers has the structure of aromatics, which are UV-active and show a distinct UV spectrum, UV spectrophotometry is a very efficient analytical method for qualitative and quantitative analysis of stabilisers and similar substances in polymers. For UV absorbers, UV detection (before and after chromatographic separation) is an appropriate analytical tool. Haslam et al. [30] have used UV spectroscopy for the quantitative determination of UVAs (methyl salicylate, phenyl salicylate, DHB, stilbene and resorcinol monobenzoate) and plasticisers (DBP) in PMMA and methyl methacrylate-ethyl acrylate copolymers. From the intensity ratio... 

Resorcinol may be released to the environment in waste effluents associated with coal gasification and conversion, coal-tar production and shale oil processing and from the combustion of wood and tobacco. It has been detected in low levels in groundwater samples (United States National Library of Medicine, 1997). 

Exposure to resorcinol may occur in its production, in the manufacture of adhesives, rubber, wood products, dyes and pharmaceuticals. It has been detected at low levels in groundwater and occurs in wood smoke and tobacco smoke. 

Recently, dopamine and catechol were detected using voltammetric MIP chemosensors [138]. Here, again, the chemosensors could determine dopamine and catechol in the presence of excess of interfering compounds, such as phenol, resorcinol, hydroquinone, serotonine, ascorbic acid, etc. For catechol, LOD was 228 nM and the linear concentration range was linear from 228 nM to 144 pM. 

The mechanism for the breakdown of phenol after hydroxylation of benzene can be seen in Figure 12.1. Several dihydroxy-substituted phenol derivatives were observed upon irradiation hydroquinone, catechol, and trace amounts of resorcinol (Nickelsen et al., 1993a,b). However, hydroquinone and catechol were both formed at the highest concentration at a low absorbed dose and their concentration decreased with increasing radiation to below detection limits at a dose of 300 krad. At a pH of 9 and a dose of 100 krad, dihydroxy-substituted phenol concentrations increased. When the pH was 5 and 7, the maximum concentrations of these products were found at 50 krads, suggesting a more efficient removal at a lower pH. 

The fractions and amounts were analogous to those of Figure 2, except for the total fractions (t), where 20 pg glycolipid were used. Bands for N-acetyl (a) and N-glycoloyl (b) type of hematoside are indicated. Resorcinol was used for the detection, and the solvent war methyl acetate-2-propanol-CaClt (8 mg/mL)-NH, (5M) 45 35 15 10 (by... 

The refractive index detector was one of the first on-line HPLC detectors used. Detection is based on changes in the refractive index of the effluent when an analyte is present versus the solvent alone. This detector is commonly used when an analyte does not have a suitable UV chromophore. An example would be the detection of carbohydrates in drug preparations or acetylcholine in an ophthalmic solution [102,103]. Figure 5.4 is a chromatogram of propylene glycol, propylene carbonate, and resorcinol in anhydrous ointment detected by a refractive index detector [104]. 

Improvements in separations ability offered by the Dionex HPIC-CS5 column, which exhibits both anion and cation exchange capacity, have allowed the determination of ten metal ions in a single injection with a pyridine-2,6-dicarboxylic acid (PCDA) eluent (Fig. 2.3). The post-column reagent used in the detection scheme was 4-(2-pyridylazo) resorcinol. 

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