Ethyl /?-hydroxyisovalerate

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. 10.1 Metabolites in the urine of an untreated patient with branched-chain keto aciduria (maple syrup urine disease). Extracted using ethyl acetate and separated as their trimethylsilyl-oxime derivatives on a 25 m SE-30 capillary column, using temperature programming from 80°C to 110°C at 0.5°C min and an injection split ratio 1 12 at a temperature of 250°C. The peaks marked R are due to solvent and reagents. Peak identifications are 1, lactic 2, 2-hydroxyisobutyric 3, 2-hydroxybutyric 4, pyruvic 5, 3-hydroxybutyric 6, 2-hydroxyisovaleric 7, 2-oxobutyric 8, 2-methyl-3-hydroxy-isovaleric 10, a and b, 2-oxoisovaleric 11, acetoacetic 12, 2-hydroxyisocaproic 13, 2-hydroxy-3-methyl- -valeric 14, 2-oxo-3-methyl-/i-valeric (14a L- 14b D-) 15, 2-oxoisocaproic acids. The internal standard was malonic acid. (Redrawn with modifications from Jellum etal., 1976)...

Fig. 10.8 Chromatogram of organic acids extracted using ethyl acetate and diethyl ether from the urine of a patient with isovaleric acidaemia and separated as their trimethylsilyl derivatives on 3 per cent OV-1 by temperature programming from 90°C to 300°C at 3°C min S after co-injection with a standard alkane mixture. Peak identifications are 1, C12 alkane 2, 3-hydroxyisovalerate 3, C14 alkane 4, mono-TMS-isovalerylglycine 5, Cie alkane 6, C18 alkane, 7, C20 alkane 8, C22 alkane. (Redrawn with modifications from Ando etaLy 1973)...

Fig. 10.17 Chromatogram of organic acids extracted using ethyl acetate from the urine of a patient with 3-hydroxy-3-methylglutaric aciduria separated as their trimethylsilyl derivatives on 6 per cent Apiezon N on Chromosorb W (DMCS) (80-100 mesh) using temperature programming from 80 C to 250°C at 6°C min Peak identifications are 1, 3-hydroxyisovalerate 2, 3-methylglutarate 3 and 4, 3-methylglutaconate peaks 5, 3-hydroxy-3-methylglutarate. (Redrawn with modifications from Faull et al, 1976b)...

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