Urinary phenolic acids by thin-layer chromatography

Routine Laboratory Investigation of Urinary Catecholamine Metabolites in Sick Children

“…2). It is valuable for the investigation of disorders of phenylalanine and tyrosine metabolism and has been recommended for the detection of catecholamine metabolites (Ersser et al, 1970;Ebinger et al, 1975;Wadman et al, 1976). Its main disadvantages are: (a) that mild increases in HMMA excretion are not readily apparent on simple visual inspection; (b) semiquantitation of irregularly shaped spots is prone to unacceptably large errors; (c) the di-hydroxy compounds are destroyed by the alkaline solvent used in the first dimension; (d) the area of the chromatogram occupied by HMMA can be crowded with glycine conjugates of exogenous phenolic acids jf dietary restriction is impracticable (Seakins and Smith, 1976).…”

“…A two-dimensional chromatogram on microcrystalline cellulose (Schleicher and Schuell F.1440, Anderman and Co, E. Molesey, Surrey) was prepared using a second aliquot of the extract as described by Ersser et al (1970). Layers of 50 mm square were used as the process could be completed in one hour.…”

Dihydropteridine reductase deficiency in an 18‐year‐old boy

“…Neopterin and total biopterin (includes BH2 and BH4) were measured in plasma and urine by high performafi'c'e liquid chromatography (HPLC) (Young et al~/1982 ). BH4 in urine was measured by selective alkaline oxidation (Fukushima and Nixon, 1980), noradrenaline and dopamine by HPLC (Moyer et al, 1979) and phenolic acids by thin layer chromatography (Ersser et al, 1970). Dihydropteridine reductase was determined in lymphocytes isolated from 5 ml fresh blood (Young et at., 1982).…”

Hyperphenylalaninaemia of various types among three-quarters of a million neonates tested in a screening programme.

“…The method4 was based on the principles given by Guthrie and Susi5 except that after December 1974 the Guthrie cards were not autoclaved before assay. Phenylalanine was semiquantitated by reference to standard blood spots containing 60-1200 Vmol/l (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) Vmol/l (4 mg/100 ml) was accepted as a negative result provided some growth was visible around the disc on the Guthrie plate. Every positive test, no matter how small the increase in phenylalanine, was followed up until a negative screening test was obtained or a definitive diagnosis was reached.…”