Retinol, alpha-tocopherol, lycopene, and alpha- and beta-carotene simultaneously determined in plasma by isocratic liquid chromatography.

1986 ◽  
Vol 32 (5) ◽  
pp. 874-876 ◽  
Author(s):  
D B Milne ◽  
J Botnen
Keyword(s):  
Liquid Chromatography ◽  
Internal Standard ◽  
Beta Carotene ◽  
Reversed Phase ◽  
Small Sample ◽  
Alpha Tocopherol ◽  
Organic Layer ◽  
Retinyl Acetate ◽  
Mobile Phase Flow Rate ◽  
Short Run

Abstract Retinol, alpha-tocopherol, lycopene, and alpha- and beta-carotene can be simultaneously determined in human plasma by reversed-phase liquid chromatography. Plasma--0.5 mL plus added internal standard, retinyl acetate--is deproteinized with 0.5 mL of ethanol, then extracted with 1.0 mL of petroleum ether. The organic layer is removed and evaporated, the residue is redissolved in 0.25 mL of ethanol, and 8-microL samples are injected into a 60 X 4.6 mm column of Hypersil ODS 3-microns particles at 35 degrees C. An isocratic methanol mobile phase, flow rate 0.9 mL/min, is used for the 9-min run. Retinol and retinyl acetate are monitored at 305 nm, the tocopherols at 292 nm, and the carotenoids at 460 nm. Between-run CVs were 3.1, 6.9, 6.1, and 6.5% for retinol, alpha-tocopherol, lycopene, and beta-carotene, respectively. Small sample requirement, simplicity of extraction, short run time, and good reproducibility make this procedure ideal for clinical or research use.

scholarly journals Rapid quantification of alpha-tocopherol in plasma and low- and high-density lipoproteins

1996 ◽  
Vol 42 (3) ◽  
pp. 430-435 ◽  
Author(s):  
E Teissier ◽  
E Walters-Laporte ◽  
C Duhem ◽  
G Luc ◽  
J C Fruchart ◽  
...  
Keyword(s):  
Internal Standard ◽  
Tocopherol Content ◽  
Reversed Phase ◽  
Small Sample ◽  
Alpha Tocopherol ◽  
High Density Lipoproteins ◽  
Organic Layer ◽  
Ethanol Mixture ◽  
Assay Time

Abstract We have developed two methods for measuring the alpha-tocopherol content in plasma and lipoproteins (LDL and HDL). In procedure 1, plasma or lipoproteins are deproteinized with ethanol containing delta-tocopherol as internal standard and then extracted with hexane or ethyl acetate. The organic layer is removed and evaporated, and the residue is redissolved in methanol and injected into a reversed-phase HPLC. In procedure 2, plasma or lipoproteins are diluted in a methanol and ethanol mixture containing the same internal standard. The solution is vortex-mixed, centrifuged, and directly injected into the column. The tocopherols are eluted with an isocratic methanol mobile phase at a flow rate of 1 mL/min and detected by fluorescence (lambda(exc)= 295 nm, lambda(em)= 330nm). Recoveries are approximately 100% in both cases. Between-run CVs were 8.39% for procedure 1 and 6.55% for procedure 2. Small sample requirement, simplicity of sample preparation, short assay time, and good reproducibility make procedure 2 ideal for clinical or research use. This method was applied to determination of alpha-tocopherol in plasma of patients whose diet was supplemented with alpha-tocopherol and in LDL and HDL.

Determination of retinol, alpha-tocopherol, and beta-carotene in serum by liquid chromatography with absorbance and electrochemical detection.

1987 ◽  
Vol 33 (9) ◽  
pp. 1585-1592 ◽  
Author(s):  
W A MacCrehan ◽  
E Schönberger
Keyword(s):  
Electrochemical Detection ◽  
Chromatographic Separation ◽  
Protein Denaturation ◽  
Internal Standard ◽  
Beta Carotene ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Alpha Tocopherol ◽  
Phase Gradient

Abstract We describe a method for the determination of retinol, alpha-tocopherol, and beta-carotene in serum, using a liquid-chromatographic separation with wavelength-programmed ultraviolet/visible absorbance and amperometric electrochemical detection with a glassy carbon electrode. After protein denaturation and addition of an internal standard, tocol, 250-microL samples are twice extracted with hexane. The reversed-phase, gradient-elution chromatographic separation provides baseline resolution of: the all-trans isomer of retinol from the cis isomers, alpha- from gamma-tocopherol, and all-trans-beta-carotene from alpha-carotene and from cis-beta-carotene isomers. The linearity of response and the detection limits for the two detectors for the three analytes are measured. A comparison of the values obtained for serum extracts shows good agreement between the absorbance and electrochemical detectors.

Concurrent liquid-chromatographic assay of retinol, alpha-tocopherol, beta-carotene, alpha-carotene, lycopene, and beta-cryptoxanthin in plasma, with tocopherol acetate as internal standard.

1988 ◽  
Vol 34 (2) ◽  
pp. 377-381 ◽  
Author(s):  
D I Thurnham ◽  
E Smith ◽  
P S Flora
Keyword(s):  
Quality Control ◽  
Mobile Phase ◽  
Sodium Dodecyl ◽  
Internal Standard ◽  
Beta Carotene ◽  
Alpha Tocopherol ◽  
Organic Layer ◽  
Tocopherol Acetate ◽  
Liquid Chromatographic ◽  
Control Samples

Abstract A method is described for simultaneously determining retinol, alpha-tocopherol, beta-carotene, alpha-carotene, lycopene, and beta-cryptoxanthin in 0.25 mL of plasma. Plasma mixed with sodium dodecyl sulfate is deproteinized with ethanol containing tocopherol acetate, then extracted with heptane. The evaporated organic layer is reconstituted with mobile phase (methanol/acetonitrile/chloroform, 47/47/6 by vol) and injected onto a 100 x 4.6 mm 3-micron column of Spherisorb ODS-2 (LKB) at 1.5 mL/min. The alpha- and beta-carotenes are well resolved during the 6.5-min run. Retinol is monitored at 325 nm, the tocopherols at 292 nm, and the carotenoids at 450 nm. Extraction of concentrations as great as 135 mumol/L is complete. Intrabatch CVs were 1.7%, 2.3%, 4.1%, 10.4%, 6.4%, and 3.6% for retinol, alpha-tocopherol, beta-carotene, alpha-carotene, lycopene, and beta-cryptoxanthin, respectively. Interbatch CVs for measurements on 30 occasions over 11 weeks were about 10% for all components except alpha-tocopherol (5.3%). Results agree well with those for retinol, alpha-tocopherol, and beta-carotene in quality-control samples.

Beta-carotene determined in serum by liquid chromatography with an internal standard.

1983 ◽  
Vol 29 (6) ◽  
pp. 1042-1044 ◽  
Author(s):  
W J Driskell ◽  
M M Bashor ◽  
J W Neese
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Methylene Chloride ◽  
Internal Standard ◽  
Beta Carotene ◽  
Solvent System ◽  
Peak Height ◽  
Reversed Phase ◽  
Human Populations ◽  
Relationship Of

Abstract We describe a procedure for quantitative determination of beta-carotene in human serum. The 0.1-mL serum sample is precipitated with ethanol containing the internal standard, dimethyl-beta-carotene, then extracted with hexane. This extract is injected onto a reversed-phase, "high-performance" liquid-chromatography column, and the carotenes are resolved and eluted with an acetonitrile/methylene chloride isocratic solvent system. They are quantified from the peak-height ratios of their absorbance at 450 nm. About 14 min is required for each chromatogram. The procedure has excellent precision and is appropriate for routine use in analysis of large numbers of samples. The method should be particularly useful for clinical studies on the relationship of serum beta-carotene and cancer incidence in human populations.

Determination of vitamin E in microsamples of serum by liquid chromatography with electrochemical detection.

1985 ◽  
Vol 31 (6) ◽  
pp. 880-882 ◽  
Author(s):  
P P Chou ◽  
P K Jaynes ◽  
J L Bailey
Keyword(s):  
Liquid Chromatography ◽  
Vitamin E ◽  
Electrochemical Detection ◽  
High Performance ◽  
Internal Standard ◽  
Small Sample ◽  
Alpha Tocopherol ◽  
Tocopherol Concentration ◽  
Minimum Concentration

Abstract In this procedure for determination of vitamin E by "high-performance" liquid chromatography with electrochemical detection, 25-microL serum specimens are deproteinized with ethanol. Vitamin E (alpha-tocopherol), its derivatives (beta- and gamma-tocopherols), and the internal standard (delta-tocopherol) are extracted into heptane and the extract is evaporated and the residue reconstituted with methanol before injection into the chromatograph. Within- and between-run CVs for an alpha-tocopherol concentration of 13.6 mg/L were 5.1% (n = 28) and 6.0% (n = 5), respectively. The standard curve is linear to 100 mg/L; the minimum concentration detectable is 0.1 mg/L. Analytical recovery ranged from 99.8% to 104.8%. In 36 specimens collected from apparently healthy subjects who were not taking vitamin supplements, alpha-tocopherol as determined by this method ranged from 4.3 to 9.7 mg/L, from 1.8 to 3.9 mg/L for beta- and gamma-tocopherols. Results by this method (y) and an HPLC-ultraviolet method (x) correlate reasonably (r = 0.81): y = 0.88x - 0.55 mg/L (n = 45). This procedure is adaptable to automated analysis, and the small sample requirement facilitates its applicability to neonates.

Determination of serum alpha-tocopherol (vitamin E) by high-performance liquid chromatography.

1978 ◽  
Vol 24 (4) ◽  
pp. 585-590 ◽  
Author(s):  
A P De Leenheer ◽  
V O De Bevere ◽  
A A Cruyl ◽  
A E Claeys
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Alpha Tocopherol ◽  
Gas Chromatography Mass Spectrometry ◽  
Gas Liquid Chromatography ◽  
Total Analysis ◽  
Liquid Chromatographic

Abstract We report a fast, simple high-performance liquid-chromatographic assay for serum alpha-tocopherol, with use of a reversed-phase column and tocol as internal standard. Only 200 microliter of serum is required. Isocratic elution of the n-hexane extract is done within 6 min; total analysis time is less than 1 h. Within-day precision (CV) was 2.3% for 24 samples of a normal plasma pool (mean concn, 10.1 mg/liter). Day-to-day precision (CV) was 3.2%, measured for 20 days for a specimen with a concentration of 10.8 mg/liter. Analytical recovery of alpha-tocopherol from fortified serum was 89 to 100%. The lower detection limit of alpha-tocopherol is estimated to be 0.6 mg/liter. The specificity of the procedure was verified by spectrophotometry, gas-liquid chromatography, and combined gas chromatography/mass spectrometry of an eluate collected from the column.

scholarly journals The Determination of Six Ionophore Coccidiostats in Feed by Liquid Chromatography with Postcolumn Derivatisation and Spectrofotometric/Fluorescence Detection

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Małgorzata Olejnik ◽  
Piotr Jedziniak ◽  
Teresa Szprengier-Juszkiewicz
Keyword(s):  
Drug Resistance ◽  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Internal Standard ◽  
Reversed Phase ◽  
Feed Additives ◽  
Core Shell ◽  
Proficiency Tests ◽  
Reversed Phase Hplc

The control of levels of anticoccidial feed additives in targeted feeds plays an important role in the assurance of efficiency of animal treatment, prevention of drug resistance, and food safety. The robust and labour-efficient method for the simultaneous determination of six ionophore coccidiostats (lasalocid, maduramicin, monensin, narasin, salinomycin, and semduramicin) in targeted feed has been developed. Properly grinded and homogenized feed sample was spiked with internal standard (monesin methyl ester) and extracted with methanol. The extract was analysed with reversed phase HPLC without any further purification. The separation of the analytes with conventional C18 and core-shell columns was compared. Lasalocid was analysed with fluorescence detection, whereas other ionophores were detected with UV-Vis detector after derivatisation with vanillin in the presence of sulfuric acid. Fortified samples and targeted feeds at authorized levels were used for method validation. Recovery was in the range of 85–110%, depending on the analyte. The within-laboratory reproducibility did not exceed the target value from Horwitz equation. The results of the proficiency tests (z-scores in the range of −1.0 to 1.9) confirmed the reliability of the developed protocol.

Determination of urinary normetanephrine and metanephrine by radial-compression liquid chromatography and electrochemical detection.

1983 ◽  
Vol 29 (2) ◽  
pp. 305-309 ◽  
Author(s):  
P J Orsulak ◽  
P Kizuka ◽  
E Grab ◽  
J J Schildkraut
Keyword(s):  
Liquid Chromatography ◽  
Electrochemical Detection ◽  
Depressive Disorders ◽  
Internal Standard ◽  
Normal Subjects ◽  
Reversed Phase ◽  
Radial Compression ◽  
Ion Pair Chromatography ◽  
Catecholamine Metabolites

Abstract A procedure has been developed for determining the O-methylated catecholamine metabolites, normetanephrine and metanephrine, in urine by use of radial-compression liquid chromatography followed by electrochemical detection. Normetanephrine and metanephrine are isolated from hydrolyzed urine by ion-exchange on small, commercially available, disposable columns and preconcentrated by solvent extraction. They are then separated by reversed-phase ion-pair chromatography, with use of a radial compression cartridge and radial compression module, and quantified with 3-methoxy-4-hydroxybenzylamine as internal standard. Normetanephrine, metanephrine, and the internal standard are separated from interfering peaks in about 15 min. The method is applicable to the relatively low amounts of normetanephrine (100-600 micrograms/24 h) and metanephrine (50-400 micrograms/24 h) found in normal subjects and patients with depressive disorders or hypertension. Within-day CVs ranged from 1.1 to 2.2% for normetanephrine and 1.2 to 6.9% for metanephrine; the corresponding between-day CVs were 4.9 and 5.7% over these ranges.

Simultaneous determination of vitamins A and E and carotenoids in plasma by reversed-phase HPLC in elderly and younger subjects

1993 ◽  
Vol 39 (11) ◽  
pp. 2229-2234 ◽  
Author(s):  
Z Zaman ◽  
P Fielden ◽  
P G Frost
Keyword(s):  
Simultaneous Determination ◽  
High Performance ◽  
Ammonium Acetate ◽  
Beta Carotene ◽  
High Performance Liquid Chromatographic ◽  
Solvent Mixture ◽  
Reversed Phase ◽  
Alpha Tocopherol ◽  
Elderly Subjects

Abstract A reversed-phase high-performance liquid-chromatographic method for the simultaneous determination of retinol, alpha-tocopherol, alpha-carotene, beta-carotene, cryptoxanthin, lutein/zeaxanthin, and lycopene is described. This method was applied to plasma measurements in healthy young and elderly subjects. The plasma, deproteinized with ethanol, is extracted twice with n-hexane. After evaporation, the residue is dissolved in 50 microL of tetrahydrofuran and made up to 200 microL with ethanol. Samples (50 microL) are injected onto a 250 x 4.6 mm column of 5-microns-particle Spherisorb ODS1 (Phase Separations) that had been equilibrated with solvent mixture A:B (90:10 by vol) [A = 100 mmol/L ammonium acetate in methanol: acetonitrile (80:20 by vol) and B = 100 mmol/L ammonium acetate in water] at 2 mL/min. The analytes are eluted by running a 12-min linear gradient to 100% A; solvent A is then maintained for 10 min. Intrabatch CVs were 2.3%, 3.3%, 2.8%, 3.6%, 3.6%, and 3.0% for retinol, alpha-tocopherol, lutein/zeaxanthin, cryptoxanthin, lycopene, and beta-carotene, respectively. The corresponding interbatch CVs were 4.9%, 5.8%, 12.3%, 6.5%, 8.0%, and 3.4%.

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