Aromatic acids chromatography

Lange, H.W. and Hempel, K., Automated chromatography of aromatic acids, aldehydes, and alcohols with an amino acid analyzer, /. Chromatogr., 59, 53,1971. 

The prediction of retention times in a given eluent from log P has been proposed for aromatic hydrocarbons.19 The log A values of phenols21 and nitrogen-containing compounds22 were also related to their logP, and the calculated log P was used for the qualitative analysis of urinary aromatic acids, i.e. for the identification of metabolites in urine from the differences of log P in reversed-phase liquid chromatography.23,24... 

The agreement between the observed and predicted k values of aromatic acids was within 10%. The correlation coefficient was 0.954 (n = 32). An error of greater than 10% for 3-hydroxy-2-naphthoic acid and 2-hydroxybenzoic acid was attributed mainly to an error in their K.A values.25 The partition coefficient, logP, and dissociation constant, pKA, of analytes can be obtained by simple calculations and by computational chemical calculations, and thus the retention time can be predicted in reversed-phase liquid chromatography. 

Fio. 36. Vloi t Hoff plou of the retention bctors of aromatic acids in reversed-phase chromatography using octadecyl silica as the stationaiy phase and neat aqueous 30 taM NaHiPO buffer (pH 2.0) (open symbols), or the same buffer containing 696 (v/v) of aceloni ti (closed symbols) as the eluent. Column S imSpherisorbODS, 230 x 4.6 mm. Eluites 3.4xlihydroxymandelic acid (O. ) 4 hydroxymandelic acid ( , ) 4-hydroxyphenylacetic acid (7. ) 3,4-dihydroxyphenylacetic acid (A, A). Reprinted with permission from Me-lander tt at. U77). 

Similar expressions have been obtained for the particular cases of mono-protic acids and bases, diprotic acids and bases, and zwitterions (207, 208), and in each case the data conformed well to Eq. (111). It has also been shown (207) that the acid dissociation constants can be determined by using reversed phase chromatography. The pIK, values of 10 aromatic acids calculated from chromatographic data by employing Eq. (91) were... 

Other applications of gas chromatography-mass spectrometry include (Table 16.1) the following polyaromatic hydrocarbons, esters, phenols, aromatic acids, chlorophenols, glycols, hydroxybenzenes, 1 4 dioxane, propiolactone, vinyl chloride,... 

Using aminopropyl-modified silica gel plates in a normal phase system, the retention behavior of 12 acidic drugs and biologically active aromatic acids was investigated by high-performance thin layer chromatography. 

Aromatic acids are strongly retained because of the interactions described above. Thus, they should not be analyzed by ion-exclusion chromatography. The high retention of unsaturated and aromatic moieties on ICE stationary phases is unlike the behavior on ODS phases, where n-n interactions are not possible and where only the enhanced solubility in the eluent comes to fruition. 

Aromatic acids absorb well and methods for detecting these anions are powerful. The usefulness of direct UV detection can be considered to be limited because sulfate is not detected by UV, and chloride, phosphate and others are difficult to detect. Sulfate is probably the most widely analyzed anion by ion chromatography so this is a serious limitation. On the other hand, anions that are difficult to detect make ideal eluent anions. 

Fan, X. and Deng, Y., Separation and identification of aromatic acids in soil and the Everglades sediment samples using solid-phase microextraction followed by capillary zone electrophoresis. Journal of Chromatography, A, 979, 417, 2002. 

T. Hanai, Chromatography in silica, quantitative analysis of retention of aromatic acid derivatives,/. Chromatogr. Set, 2006, 44, 247-252. 

T. Hanai, K. C. Tran and J. Hubert, Prediction of retention times for aromatic acids in liquid chromatography,/. Chromatogr., 1982,239,385-395. 

T. Hanai and J. Hubert, Optimization of retention time of aromatic acids in liquid chromatography from log P and predicted pKa values,/. High Resolut. Chromatogr. Chromatogr. Commun., 1984, 7, 524-528. 

Jones, P. Wellington, C.A. Optimisation in chromatography Theory and application to the separation of aromatic acids in reversed-phase liquid chromatography. J. Chromatogr. 1981, 213, 357-361. 

Polyvinylpyrrolidine has been shown to be very suitable as the sorbent for the separation of humic materials, tannins, lignins, as well as organic dye compounds, phenolic materials, aldehydes, and aromatic acids. Non-polar solid-phase extraction can be used for the preconcentration of heavy metals as complex compounds and their subsequent determination by cation-exchange chromatography. 

Gas Chromatography of Aromatic Acids as Their Trimethylsilyl Derivatives, Including Applications to Urine Analysis... 

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