Linked Life Data

8205240

Source:http://linkedlifedata.com/resource/pubmed/id/8205240

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1994-7-11
pubmed:abstractText
Several modifications of an HPLC-electrochemical assay method for plasma levels of norepinephrine (NE), epinephrine (EPI), dopamine (DA), dihydroxyphenylglycol (DHPG), dihydroxyphenylalanine (DOPA) and dihydroxyphenylacetic acid (DOPAC) that improve the accuracy and reliability of DHPG, DOPA, and DOPAC measurements are described. In batch alumina extractions, increasing the amount of alumina decreased analytical recoveries of DHPG, DOPA, and especially DOPAC, and increasing the strength of the eluting acid increased recoveries of these catechols, without affecting recoveries of the amines NE, EPI and DA. Refrigeration (4 degrees C) until injection stabilized DOPAC in aqueous solution and therefore improved the reproducibility of plasma DOPAC measurements. Circulation of chilled water (15 degrees C) around the column using a water jacket decreased variability in retention times of the catechols and thereby facilitated identification of peaks, while enhancing separation of DHPG from the solvent front. Use of 6-fluoro-DOPA and 6-fluoro-DOPAC as internal standards did not improve inter-assay reliability. We recommend that in assays of plasma catechols including DOPAC, small (5 mg), precisely measured amounts of alumina be used, with a relatively strong eluting solution (e.g. 0.04 M phosphoric acid-0.2 M acetic acid, 20:80, v/v), and that the samples be refrigerated until injection, with column temperature held constant at less than 20 degrees C.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1572-6495
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
653
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
131-8
pubmed:dateRevised
2007-10-16
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Improved assay for plasma dihydroxyphenylacetic acid and other catechols using high-performance liquid chromatography with electrochemical detection.
pubmed:affiliation
Clinical Neuroscience Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.
pubmed:publicationType
Journal Article