A rapid HPLC method for monitoring plasma levels of caffeine and theophylline using solid phase extraction columns.

Abstract:

:A simple HPLC method for the determination of caffeine and theophylline in plasma is described. Separation of theobromine, paraxanthine, theophylline, beta-hydroxyethyltheophylline and caffeine is obtained using a mobile phase of 1% acetic acid/methanol (83:17, v/v) and a Waters Associates NOVA-PAK C18 column protected by a Guard-PAK precolumn module containing a Guard-PAK CN cartridge. Rapid sample preparation is achieved by solid-phase extraction columns (Bond-Elut C18, 1 mL capacity) which provide excellent recovery values for both drugs. The cost per sample using this approach can be minimised by column regeneration and re-use. Results obtained for theophylline are in good agreement with values determined by other techniques.

journal_name

Ann Clin Biochem

authors

Pickard CE,Stewart AD,Hartley R,Lucock MD

doi

10.1177/000456328602300410

subject

Has Abstract

pub_date

1986-07-01 00:00:00

pages

440-6

eissn

0004-5632

issn

1758-1001

journal_volume

23 ( Pt 4)

pub_type

杂志文章
  • Evaluation of 25-hydroxy vitamin D assay on the immunodiagnostic systems iSYS analyser.

    abstract:BACKGROUND:We evaluated the recently released chemiluminescence assay for 25-hydroxy vitamin D (25-OHD) on the Immunodiagnostic Systems iSYS (IDS-iSYS) automated analyser. METHODS:The IDS-iSYS comparison was performed using patient samples previously measured for 25-OHD by a validated liquid chromatography-tandem mass...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1258/acb.2011.011018

    authors: Cluse ZN,Fudge AN,Whiting MJ,McWhinney B,Parkinson I,O'Loughlin PD

    更新日期:2012-03-01 00:00:00

  • Measurement of copper, zinc and magnesium in serum and urine by DC plasma emission spectrometry.

    abstract::The application of a DC plasma emission spectrometer to the measurement of copper, zinc and magnesium in serum and urine is reported. Each assay requires only a simple dilution in 1% nitric acid. Comparisons with standard atomic absorption techniques showed good analytical agreement, especially for copper and magnesiu...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456328502200512

    authors: Roberts NB,Fairclough D,McLoughlin S,Taylor WH

    更新日期:1985-09-01 00:00:00

  • A combined laboratory and field evaluation of the Cholestech LDX and CardioChek PA point-of-care testing lipid and glucose analysers.

    abstract:BACKGROUND:Combined lipid and glucose point-of-care testing (POCT) devices could facilitate widespread population screening for cardiovascular disease (CVD) and diabetes as part of the NHS Vascular Risk Assessment and Management Program (NHS Health Checks). An evaluation of the Cholestech LDX and CardioChek PA POCT ana...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/0004563213482890

    authors: Whitehead SJ,Ford C,Gama R

    更新日期:2014-01-01 00:00:00

  • Alkaline phosphatase activity measurement in the UK by AMP-buffered methods: an appraisal of current practice.

    abstract::Most UK clinical laboratories use alkaline phosphatase (ALP) methods similar to that proposed by the International Federation of Clinical Chemistry (IFCC), based on the use of 2-amino-2-methyl-1-propanol (AMP) buffer. We present evidence of significant differences in results produced by apparently similar commercial A...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456329803500117

    authors: Lamb EJ,Browne M,John WG,Price CP

    更新日期:1998-01-01 00:00:00

  • Quantitative turbidimetric assay for determining myoglobin evaluated.

    abstract::A recently introduced turbidimetric immunoassay using shell/core particles for determination of myoglobin (Turbiquant Myoglobin, Behringwerke, Marburg, Germany) was evaluated on the Behring Turbitimer analyzer. Intra-assay CV varied between 1.0% and 3.2%; interassay CV was between 2.0% and 3.6%. Linear results were ob...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456329102800509

    authors: Delanghe J,Chapelle JP,el Allaf M,De Buyzere M

    更新日期:1991-09-01 00:00:00

  • Measurement of erythrocyte acetylcholinesterase and plasma cholinesterase activity by a differential pH technique.

    abstract::We describe a new electrochemical method for the determination of erythrocyte acetylcholinesterase activity (EC 3.1.1.7) and plasma cholinesterase (EC 3.1.1.8) activity, based on the measurements of pH variation due to release of acetic acid from acetylcholine. The major advantages of the differential pH procedure are...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456328602300509

    authors: Barenghi L,Ceriotti F,Luzzana M,Ripamonti M,Mosca A,Bonini PA

    更新日期:1986-09-01 00:00:00

  • Lower value of glycated haemoglobin relative to glycaemic control in diabetic patients with end-stage renal disease not on haemodialysis.

    abstract:BACKGROUND:Glycated haemoglobin (HbA1c) concentration is lower relative to glyacemic control in diabetic patients on haemodialysis. However, it is unknown as to whether this is also true for diabetic patients with end-stage renal disease but not on haemodialysis. METHODS:Correlations between HbA1c or glycated albumin ...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1258/acb.2011.011161

    authors: Shima K,Chujo K,Yamada M,Komatsu M,Noma Y,Mizuguchi T

    更新日期:2012-01-01 00:00:00

  • Essential data derived from biological variation for establishment and use of lipid analyses.

    abstract::The analytical and biological components of variation of total cholesterol, high density lipoprotein (HDL) cholesterol, HDL3 cholesterol, HDL2 cholesterol and apolipoproteins A-I and B in serum were assessed in 12 apparently healthy individuals. All analytes showed marked individuality and therefore conventional popul...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456328902600314

    authors: Ford RP

    更新日期:1989-05-01 00:00:00

  • The analysis of bilirubin in serum.

    abstract::The most widely used methods for the assay of total bilirubin in serum are based on a coupling reaction with various diazo dyes in the presence of an accelerating agent. The 'direct' reaction, without accelerator, gives a good estimate of the conjugated and protein bound (delta) species of bilirubin only if carefully ...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章,评审

    doi:10.1177/000456329102800202

    authors: Westwood A

    更新日期:1991-03-01 00:00:00

  • Stabilization of circulating thyroglobulin mRNA transcripts in patients treated for differentiated thyroid carcinoma.

    abstract::Background The clinical utility of serum thyroglobulin in the follow-up of patients with differentiated thyroid carcinoma may be compromised by the presence of endogenous antithyroglobulin antibodies. To prevent interference by antithyroglobulin antibodies several groups have developed real-time PCR-based assays for q...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/0004563216671538

    authors: Feddersen S,Bastholt L,Pedersen SM

    更新日期:2017-09-01 00:00:00

  • Body composition and plasma creatine kinase activity.

    abstract::Plasma creatine kinase (CK) activity and lean body mass (LBM) (by anthropometry) were measured in 120 women (20-82 years) and 70 men (20-82 years). Plasma CK activity and LBM was higher in men than in women. In men plasma CK activity was significantly correlated (product moment correlation coefficient) with LBM and ne...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456328802500411

    authors: Swaminathan R,Ho CS,Donnan SP

    更新日期:1988-07-01 00:00:00

  • Clinical relevance of serum amyloid A protein monitoring in urinary tract infections.

    abstract::We have evaluated the clinical relevance of monitoring acute phase proteins in severe urinary tract infection. Body temperature, white blood cell count, erythrocyte sedimentation rate, serum amyloid A protein (SAA), C-reactive protein (CRP), alpha-1-antichymotrypsin (ACT) and alpha-1-acid glycoprotein (AGP) were deter...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456329303000308

    authors: Casl MT,Sabljar-Matovinović M,Kovacević S,Pocanić D,Preden-Kereković V,Jagarinec N

    更新日期:1993-05-01 00:00:00

  • The case of stainless statins.

    abstract::Two cases of hypercholesterolaemic patients are presented in whom raised plasma creatine kinase was noted during treatment with statins. The plasma creatine kinase failed to fall following cessation of therapy. Further investigation revealed the aetiology of the raised plasma creatine kinase to be due to previously un...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1258/000456303322326542

    authors: Barth JH,Brownjohn AM,Jamieson DR

    更新日期:2003-09-01 00:00:00

  • Recurrent dizzy spells: all in the head!

    abstract::Hypoglycaemia is an uncommon manifestation of hypopituitarism in non-diabetic adults. A 47-year-old woman with Cushing's disease was treated with bilateral adrenalectomy and pituitary radiotherapy following unsuccessful trans-sphenoidal surgery. Twenty years later, she presented with a tonic-clonic seizure and recurre...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:

    authors: McAulay V,Seckl JR,Strachan MW

    更新日期:2005-01-01 00:00:00

  • Identification of factors limiting the accurate measurement of plasma D-penicillamine in rheumatoid arthritis patients.

    abstract::Free and total reduced concentrations of D-penicillamine have been measured in the plasma of rheumatoid arthritis patients by HPLC and electro-chemical detection. A reverse-phase ion-pair separation in conjunction with a dual porous graphite electrode satisfied the requirements of robustness, sensitivity, selectivity ...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456328802500210

    authors: Webb BA,Richardson SJ,Haslock I

    更新日期:1988-03-01 00:00:00

  • The significance of serum troponin T in patients with kidney disease: a review of the literature.

    abstract::The last 10 years have witnessed radical changes in the definition and diagnosis of the acute coronary syndrome (ACS), including myocardial infarction, as a result of the introduction of sensitive and specific markers of myocardial damage, the cardiac troponins. One barrier to the universal acceptance of these markers...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章,评审

    doi:10.1258/000456304322664645

    authors: Lamb EJ,Webb MC,Abbas NA

    更新日期:2004-01-01 00:00:00

  • Identification of phosphotyrosyl proteins in vitreous humours of patients with vitreoretinal diseases by sodium dodecyl sulphate-polyacrylamide gel electrophoresis/Western blotting/matrix-assisted laser desorption time-of-flight mass spectrometry.

    abstract:BACKGROUND:It is important to explain target proteins for the understanding of the pathogenesis of vitreoretinal diseases. In a previous study, we identified more than 100 proteins including seven angiogenic-modulated factors in vitreous humours (VHs). Although there have been many reports of expressed protein profiles...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1258/acb.2007.007151

    authors: Mukai N,Nakanishi T,Shimizu A,Takubo T,Ikeda T

    更新日期:2008-05-01 00:00:00

  • Comparison of simple acid-ethanol precipitation with gel exclusion chromatography for measuring leptin binding in serum of normal subjects and cancer patients.

    abstract:BACKGROUND:In humans, leptin circulates in a free form and is also bound to macromolecules. The aim of the present study was to compare a rapid acid-ethanol precipitation (AEP) method of measuring bound leptin with the more laborious gel exclusion chromatography (GEC) reference procedure. Serum samples collected from h...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1258/000456303763046157

    authors: Jamieson NB,McMillan DC,Brown DJ,Wallace AM

    更新日期:2003-03-01 00:00:00

  • A novel five-microlitre capillary system for home glucose monitoring.

    abstract::Improvement in the control of diabetic patients is aided by a knowledge of blood glucose levels during a 'normal' (non-hospitalised) day. We have devised a 5 microliter capillary tube collection system as a 'kit' for home use by diabetics. Blood collected into 5 microliter capillary tubes is washed into a protein prec...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456328101800507

    authors: Williams CP,Davies GK,Child DF

    更新日期:1981-09-01 00:00:00

  • The ratio of erythrocyte zinc-protoporphyrin to protoporphyrin IX in disease and its significance in the mechanism of lead toxicity on haem synthesis.

    abstract::Protoporphyrin and zinc-protoporphyrin were measured in the erythrocytes of normal subjects, workers exposed to lead and patients with iron deficiency and erythropoietic protoporphyria (EPP). Results showed significantly higher levels of zinc-protoporphyrin in the lead-exposed workers (P < 0.0001), patients with iron ...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456329803500313

    authors: Nelson JC,Westwood M,Allen KR,Newton KE,Barth JH

    更新日期:1998-05-01 00:00:00

  • Comparison of two latex agglutination test kits for serum myoglobin in the exclusion of acute myocardial infarction.

    abstract::The Myolex (Orion) and the RapiTex (Behringwerke) latex agglutination tests for the rapid detection of elevated levels of serum myoglobin were studied prospectively in patients suspected of acute myocardial infarction, who were admitted to hospital within 8 h of pain onset. Using admission blood samples drawn 3.4 +/- ...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456328902600309

    authors: Konings CH,Funke Küpper AJ,Verheugt FW

    更新日期:1989-05-01 00:00:00

  • High-density lipoprotein, lipid, and carbohydrate metabolism during increasing fitness.

    abstract::Eleven unfit bank executives in sedentary employment exercised daily for 10 weeks according to the Canadian Air-Force 5BX Exercise Programme. Over this period no changes were observed in the glucose or insulin responses to a standard breakfast or to intravenous glucose, or in the glucose response to intravenous insuli...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456327901600115

    authors: Moore RA,Penfold WA,Simpson RD,Simpson RW,Mann JI,Turner RC

    更新日期:1979-03-01 00:00:00

  • A simple liquid chromatography linked to tandem mass spectrometry method for measurement of serum cholinesterase activity using succinylcholine as substrate.

    abstract:BACKGROUND:Individuals who are unable to metabolize the short-acting muscle relaxant succinylcholine due to abnormal cholinesterase activity are currently investigated via spectrophotometry using artificial substrates and enzyme inhibitors. Methods have been described using succinylcholine as substrate but with measure...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1258/acb.2010.009169

    authors: Spencer JD,Rushton D,Allen KR

    更新日期:2010-05-01 00:00:00

  • The costing of tests in a laboratory for clinical chemistry and haematology.

    abstract::The total cost of a haematology and clinical chemistry laboratory, including external and hospital costs, was studied in a district general hospital in The Netherlands. The main conclusion is that the number of samples analysed is the most important cost-setting factor, but that reduction in the number of requests doe...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456328402100206

    authors: Leijten JF,van der Geer F,Scholten MN,Goldschmidt HM

    更新日期:1984-03-01 00:00:00

  • Clinical usefulness of the simultaneous localisation of the isoenzymes of alkaline phosphate and gamma-glutamyl transferase.

    abstract::Simultaneous localisation of the isoenzymes of alkaline phosphatase and gamma-glutamyl transferase was carried out on 173 serum samples from patients with hepatobiliary and bone disease to determine (i) if a better discrimination of the underlying pathology could be obtained by such an approach, and (ii) if the pathol...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456328001700104

    authors: Baines M

    更新日期:1980-01-01 00:00:00

  • Comparison of sample types for N-terminal pro-B-type natriuretic peptide measured on the Siemens Immulite 2500 and Dimension Vista LOCI methods.

    abstract:BACKGROUND:Measurement of serum natriuretic peptides is recommended in patients with suspected heart failure. Assays for N-terminal pro-B-type natriuretic peptide (NT-proBNP) are available on several platforms and can be measured in serum or heparinized plasma. Siemens Healthcare Diagnostics do not recommend the use of...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1258/acb.2012.012053

    authors: Peake RW,Turner HE,Leaper W,Deans KA,Hannah A,Croal BL

    更新日期:2012-09-01 00:00:00

  • Benzodiazepine misuse by drug addicts.

    abstract::Using a high-performance liquid chromatography method, we measured seven commonly prescribed benzodiazepines (chlordiazepoxide, nitrazepam, nordiazepam, oxazepam, lorazepam, temazepam and diazepam) in 100 urine samples obtained from patients attending the Leeds Addiction Unit. All of the urines selected for investigat...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456329703400110

    authors: Garretty DJ,Wolff K,Hay AW,Raistrick D

    更新日期:1997-01-01 00:00:00

  • Why the assay of serum cystine by protein precipitation and chromatography should be abandoned.

    abstract::The higher bias of serum cystine estimations by a HPLC method compared with those by ion exchange techniques is shown to be largely due to differences in the sample preparation procedures of the two techniques. The ion exchange methods utilised sulphosalicylic acid serum protein precipitation and post-column ninhydrin...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456328802500516

    authors: Cooper JD,Turnell DC,Green B,Wright DJ,Coombes EJ

    更新日期:1988-09-01 00:00:00

  • The reduction of peripheral insulin concentrations in obese subjects following a hypocaloric diet: reduced pancreatic secretion or increased hepatic extraction?

    abstract::The fasting hyperinsulinaemia characteristic of obesity is due to pancreatic hypersecretion and is accompanied by a corresponding increase in plasma C-peptide concentrations. The exaggerated plasma insulin and C-peptide responses to oral glucose in obese subjects which is greater for insulin than C-peptide suggests th...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章

    doi:10.1177/000456328902600502

    authors: Gama R,Marks V

    更新日期:1989-09-01 00:00:00

  • High-density lipoprotein: why all the fuss?

    abstract::The current search for new treatments to combat coronary heart disease (CHD) is centred on increasing HDL-cholesterol. The failure of the CETP inhibitor torcetrapib may force a rethink. This perspective briefly reviews the antiatherosclerotic properties of HDL and ways HDL-cholesterol concentration can be raised, but ...

    journal_title:Annals of clinical biochemistry

    pub_type: 杂志文章,评审

    doi:10.1258/acb.2008.008133

    authors: Mackness B,Mackness M

    更新日期:2009-01-01 00:00:00