Phenol index

Tsao R and Yang R. 2003. Optimisation of a new mobile phase to know the complex and real polyphenolic composition towards a total phenolic index using HPLC. J Chromatogr A 1018 29-40. 

Thus, an estimation can be made of the hydrophilicity of the crown ring. The acetal-type crown ring obtained from hexaethyl-ene glycol and a higher aliphatic aldehyde is estimated to be e-quivalent to about four OE units in an alkyl POE monoether, from our study of the cloud point (11). Moroi et al. concluded, from a comparison of the cmc, that a diaza-18-crown-6 is equivalent to 20 OE units in the usual type of nonionic (12). Okahara s group evaluated the effective HLB based on the cloud point, phenol index and phase-inversion-temperature in emulsion of oil/water system and they concluded that 18-crown-6 and monoaza-18-crown-6 rings with dodecyl group are approximately equivalent to 4.0 and 4.5 units, respectively, of OE chains with the same alkyl chain (17). 

Conditions Color Tint Intensity Antho- cyanins, mg/liter Total Phenols Index Tannins, grams/ liter Tannin Conden- sation Index, V/LA... 

BS EN 13370 2003. 2003. Characterization of waste. Analysis of eluates. Determination of Ammonium, AOX, conductivity, Hg, phenol index, TOC, easily liberatable CN, F. British Standards. 

Previous pilot plant operations have shown that the effectiveness of carbon adsorption processes in removing humic substances from raw water sources is limited. Most of the commercially available active carbons with high specific surface, iodine index and phenol index have a pore size distribution with a maximum of pores of a relatively low average diameter. For reason the adsorption capacity and rate towards larger-sized molecules is quite low. This was one of the incentives for the authors to start a search for alternative activated carbons. This paper will deal with the evaluation of a first generation of such activated carbons on the basis of widely used adsorption tests and an experimental comparison of their capacity towards several humic substances. 

One of the phenol determination methods described in Standard Methods , the so-called phenol index nnmber, inclndes all, water stream distillable, phenolic compounds, which are detected photometrically after derivatization with 4-aminoantipyrine and extraction with chloroform . Here, only the total amonnt of phenols is measnred. It is impossible to distingnish between individnal phenols or to estimate the probable toxicity of the analyzed water sample. This method is important only for preliminary information about possible phenol pollution and to determine if further tests are necessary. 

The semi-deterministic method already presented, based on the deconvolution of the UV spectrum, can be used as an alternative method for the rapid estimation of the phenol index . UV spectra are acquired from raw samples and, after a pH correction (pH = 12), in order to exploit both the bathochromic and hyperchromic effects, observed for the dissociated forms of phenolic compounds (phenates). This well-known procedure is particularly useful for nitrophenols, the spectra of which present a specific adsorption between 360 and 500 nm (Fig. 19). On the other hand, phenol and 2-chlorophenol have their adsorption peak range from 250 to 360 nm. It should be noticed that below 250 nm,... 

Figure 21. Comparison between expected concentrations and estimated concentrations by UV-visible (deconvolution) method (R2 = 0.98) and standard method ("phenol index").

Wines Appellations Total phenols (index) Tannins (g/1) d(meq/l)... 

In any event, even if aging in oak barrels increases the phenol content of wine, it is by no means snre that it increases the overall tannin content, at least in red wines. Analysis has shown that the total phenol index (OD 280) only increases by a few nnits dne to wood tannins, compared to an initial valne between 50 and 60. Of course, the increase is proportionally more significant in white wines, with their much lower initial tannin content. 

Phenol index, with p-nitroaniline and extraction, and also with additional steam distillation... 

The phenol content is read off from the calibration curve against the measured extinction value from which the blank value has been subtracted. After taking into account the volume of water used, the content of phenols is then expressed in mg/1 and stated as the phenol index measured in accordance with this method. 

Phenol index with 4-aminoantipyrine without extraction after steam distillation... 

When quoting phenol index figures, it should be observed that the determination limit with this method is around 2 pg/1. 

It is frequently observed in analytical practice that the phenol index as a total parameter gives positive measured values whereas the analysis for... 

Phenols (phenol index) CgHjOH (ig/1 0.5 - Excluding natural phenols which do not react to chlorine... 

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