Direct injection of lipophilic compounds in the organic phase from liquid–liquid extracted plasma samples onto a reversed-phase column

A direct injection HPLC method for the sumultaneous measurement of serum paracetamol and salicylate is described using a Pinkerton internal surface reversed-phase column with benzoic acid as internal standard. The method is linear to at least 1000 mg/L for both drugs and shows good precision at levels of 62–500 mg/L. None of the drugs tested for interference affected the quantitation of either drug. In patient samples, the values obtained with this method correlated well with those from enzymatic paracetamol and Trinder salicylate methods.

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Improved separation of C12-C22 fatty acid phenacyl esters by reversed phase column liquid chromatography

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19862722 ◽

1986 ◽

Vol 51 (12) ◽

pp. 2722-2726 ◽

Cited By ~ 3

Author(s):

Tomáš Haniš ◽

Miroslav Smrž ◽

Pavel Klír ◽

Karel Macek ◽

Zdeněk Deyl

Keyword(s):

Volume Concentration ◽

Gradient Elution ◽

Reversed Phase ◽

Isocratic Elution ◽

Water Gradient ◽

Phenacyl Esters ◽

Acetonitrile Concentration ◽

Phase Column ◽

Reversed Phase Column ◽

Critical Pairs

Phenacyl esters of C12-C22 fatty acids were separated on Separon SGX C18 column, using a gradient elution with methanol-acetonitrile-water. The proposed gradient showed better resolution of the critical pairs C18:3-C14:0, C16:1-C20:4, and C16:0-C18:1 than the gradient elution with methanol-water or acetonitrile-water, or than the isocratic elution with methanol-acetonitrile-water. The optimum volume concentration (83%) of the sum of both methanol and acetonitrile was maintained constant for 35 min; in this period the acetonitrile concentration decreased linearly from the initial 42-60% to 0% while the methanol concentration increased from the initial 41-23% to 83% at the same rate. After 35 min the elution was completed with a methanol-water gradient. The whole analysis can be performed within 63 min at a flow rate 1 ml/min.

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4-Nitrophenol in 4-nitrophenyl phosphate, a substrate for alkaline phosphatase, as measured by paired-ion high-performance liquid chromatography.

Clinical Chemistry ◽

10.1093/clinchem/23.12.2288 ◽

1977 ◽

Vol 23 (12) ◽

pp. 2288-2291 ◽

Cited By ~ 4

Author(s):

P H Culbreth ◽

I W Duncan ◽

C A Burtis

Keyword(s):

Alkaline Phosphatase ◽

High Performance Liquid Chromatography ◽

Liquid Chromatography ◽

Flow Rate ◽

Mobile Phase ◽

High Performance ◽

Reversed Phase ◽

Nitrophenyl Phosphate ◽

Phase Column ◽

Reversed Phase Column

Abstract We used paired-ion high-performance liquid chromatography to determine the 4-nitrophenol content of 4-nitrophenyl phosphate, a substrate for alkaline phosphatase analysis. This was done on a reversed-phase column with a mobile phase of methanol/water, 45/55 by vol, containing 3 ml of tetrabutylammonium phosphate reagent per 200 ml of solvent. At a flow rate of 1 ml/min, 4-nitrophenol was eluted at 9 min and monitored at 404 nm; 4-nitrophenyl phosphate was eluted at 5 min and could be monitored at 311 nm. Samples of 4-nitrophenyl phosphate obtained from several sources contained 0.3 to 7.8 mole of 4-nitrophenol per mole of 4-nitrophenyl phosphate.

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