Phenols extraction from urine

Many of the analytical procedures for pentachlorophenol in the recent literature do not call for a hydrolysis step prior to extraction of a urine sample. During the course of our research in the development of a reliable multi-residue procedure for chlorinated phenols, we found that much more pentachlorophenol could be extracted from the urine if the sample was hydrolyzed with hydrochloric acid (23). 

For this series of experiments Oberst (98) developed a colorimetric method in which morphine values as low as 0.14 mg. per 100 ml. urine could be determined readily. The morphine was extracted by an alcohol-chloroform mixture from urine saturated with sodium bicarbonate, purified, and determined colorimetrically after the addition of Fohn-Denis phenol reagent. For combined morphine the urine was acidified with one-fifth of its volume of concentrated hydrochloric acid and boiled under a reflux condenser for 3 hr. After cooling and saturating with sodium bicarbonate, the modified urine was treated in the same manner as for the determination of morphine before hydrolysis. 

Phenol materials in apple juice have been recovered with methanol from polyamide columns (at40 C) after elution of sugars and acids with water (10). Column chromatography on alumina has been used as a first step in the identification of phenolic material from Colchicum lusitanum (II). Extrelut 20 columns have been employed in the enrichment of phenolic acids in urine from the metabolism of catecholamines (12). And in the determination of phenol and o-cresol in fresh urine, solvent extraction with diethyl ether or dipropyl ether has been used following a preliminary hydrolysis with 60% perchloric acid (13). 

For special investigations, flavin compounds can be concentrated from large volumes of urine by extraction procedures. According to Chastain et al. (18), a phenol extraction is performed by saturating urine samples with ammonium sulfate followed by centrifugation to remove solids. The supernatant fluid is shaken twice with 0.1 volume of 80% aqueous phenol and centrifuged, and the upper phenolic layers are combined. An equal volume of distilled water is added and the solution is extracted with diethyl ether to remove the phenol from the aqueous flavin-containing solution. 

Fig. 7.2 Chromatogram of acidic metabolites extracted from the urine of a normal child using DEAE-Sephadex and re-extraction with solvents after ethoxime formation and freeze-drying by reconstitution in water, acidification with hydrochloric acid, saturation with sodium chloride, and solvent extraction with diethyl ether (three times) and ethyl acetate (three times), evaporation of the solvents from the combined extracts using dry nitrogen and trimethylsilylation using the minimum quantity of BSTFA. Separated on 10 per cent OV-101 on HP Chromosorb W (80-100 mesh) by temperature programming from 110°C to 285°C at 4°C min with an initial 5 min isothermal delay. Peak identifications are 1, phenol plus lactate 2, glycollate 3, cresol 4, 3-hydroxyisovalerate 5, benzoate 6, phosphate 7, succinate 8, 3-methyladipate 9, 3-hydroxy-3-methyl-glutarate 10, 4-hydroxyphenylacetate 11, homovanillate plus some aconitate 12, hippurate 13, citrate 14, vanilmandelate 15, n-tetracosane (standard) 16, n-hexacosane (standard).

Fig. 14.10 Chromatogram of the organic acids extracted using DEAE-Sephadex with solvent re-extraction from the same urine specimen illustrated in Fig. 14.8. Separation conditions are as described for Fig. 14.8. Peak identifications are 1, lactate + phenol 2, cresol + 3-hydroxypropionate 3, 3-hydroxybutyrate 4, 3-hydroxyisovalerate 5, phosphate 6, succinate 7, 3-hydroxyhexanoate 8, 5-hydroxyhexanoate 9, glutarate 10, 3-methylglutarate 11, unidentified 12, 3-methylglutaconate 13, unidentified 14, adipate 15, 3-methyladipate 16, trihydroxybenzene 17, 2-hydroxyglutarate 18, pimelate (heptanedioate) 19, 3-hydroxy-3-methylglutarate 20, 4-hydroxy-...

A similar concept was used for other environmental applications, for example, phenoxy acids, sulfonureas, phenolic compounds, and other environmentally important persistent pollutants [68, 76, 141, 143, 155-166]. Also, in the same manner, several drugs were enriched and determined in body fluids such as urine [144-146, 167-172] or blood [147, 156, 157, 173, 174]. A very advanced apphcation of SLM for analytical purposes, where transport process was based on simple diffusion with pH adjustment of aqueous phase, is the extraction of the basic drug, bambuterol, for pretreatment of plasma samples before analysis with capfflary zone electrophoresis (CZE) [147]. Bambuterol was used as a model substance in a separation system, where either 6-undecanone or a mixture of di- -hexyl ether (DHE) and tri- -octylphosphine oxide (TOPO) was used as membrane phase. It was possible not only to achieve a very low hmit of detection ( 50 nmol/1) but also to ensure the removal of salts from the sample. It helped to obtain the low ionic strength of the blood plasma samples and permitted subsequent sample stacking in the caphlary electrophoresis step. 

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