Determination of the carotenoid phytoene in blood by high-pressure liquid chromatography

A sensitive and specific high-pressure liquid chromatographic assay was developed for the determination of phytoene in blood with an overall recovery of 86 ± 6.0% and a limit of detection of 50–100 ng per ml of blood. This method provides for rapid and simple quantitation of phytoene using 1 ml or less of blood.

The assay was used in the determination of phytoene blood levels in the dog following intravenous and oral administration of 10-mg/kg doses.     

Determination of sodium phenobarbital in animal chow by high-pressure liquid chromatography

An analytical procedure is described for determining residues of sodium phenobarbital in animal chow at levels as low as 0.14 ppm. The methanol extract is subjected to a liquid-liquid cleanup at pH 13 and 1, further cleaned up on a silica gel column and assayed by high-pressure liquid chromatography by using an ultraviolet absorption detector at 210 nm. Data concerning extraction efficiency, partition values and stability of the chemical in animal chow are also presented.     

Determination of vitamin D3 in cod-liver oil (Lebertran) by high-pressure liquid chromatography

Summary An HPLC separation of vitamin D₃ in cod-liver oil (Lebertran) on a Partisil-10-pxs (Whatman) column with a mobile phase of chloroform-n-hexaneglacial acetic acid (70301) and detection at 268 nm is described. The vitamin D₃ peak in the sample solution was positively identified by measuring absorbance ratios at different wavelengths and recording a peak spectrum with a LC 55-S digital scanner between 250–350 nm. Analytical results of analysis of 11 samples are compared with those obtained by a chemical method. The coefficient of variation of the HPLC method was found to be ± 2.4%.

---

Bestimmung von Vitamin D₃ in Lebertran durch Hochdruck-Flüssigkeits-Chromatographie

Zusammenfassung Ein Verfahren zur HPLC-Bestimmung von Vitamin D₃ in Lebertran mit Hilfe einer Partisil-10 pxs-Säule (Whatman) mit der mobilen Phase Chloroform-n-Hexan-Eisessig (70301) und UV-Detektion bei 268 nm wird beschrieben. Die Identität des Vitamin D₃-Peaks wurde zusätzlich durch eine Peakanalyse bei verschiedenen Wellenlängen sowie durch Aufnahme des Peakspektrums zwischen 250–350 nm mit einem LC-55-S Digital-Scanner sichergestellt. Die Ergebnisse von 11 Lebertranproben wurden den mit einer chemischen Methode erzielten Werten gegenübergestellt. Der Variationskoeffizient der HPLC-Methode beträgt ± 2,4%.

The author thanks Mrs. Petra Grötsch for the very efficient assistance in the experimental work. He is further indebted to Mr. R. Jöster, Perkin-Elmer Corporation, Offenbach (GFR), for recording the peak spectra with a digital scanner.     

Determination of vitamin E in different biological samples by high-pressure liquid chromatography

Summary The different methods for the determination of vitamin E in all types of biological materials are reviewed. The following subjects are dealt with: isolation of the vitamin from biological samples, foodstuffs and pharmaceuticals; instrumental aspects (injection, reversed-phase HPLC, straight-phase HPLC); standardization; detection limits.

---

Bestimmung von Vitamin E in verschiedenen biologischen Proben durch HPLC

Zusammenfassung Die Übersicht behandelt folgende Aspekte: Isolierung des Vitamins aus biologischem Material, Lebensmitteln und Pharmazeutica; instrumentelle Probleme (Injektion, reversed-phase und straight-phase HPLC); Standardisierung; Nachweisgrenzen.

     

Determination of the triglyceride composition of avocado oil by high-performance liquid chromatography using a light-scattering detector.

The triglyceride composition of avocado oil was determined by high-performance liquid chromatography using a light-scattering detector. Two avocado varieties, Fuerte and Hass, were analysed, and the qualitative composition of each was found to be similar, though quantitative differences were detected. The triglyceride composition was predicted using a system of equations based on the relationship between log k' and the molecular variables equivalent carbon number, chain length and number of double bonds for each of the fatty acids in the glycerides. A total of 24 molecular species of triglycerides were identified. The chromatographic system used successfully separated the critical pairs OOO-LOS, PaPaO-LnPP and PaOO-LOP (O = olein; L = linolein; S = stearin; Pa = palmitolein; Ln = linolenin; P = palmitin). Detector response was found to have a linear relationship with the amount of sample injected over the injection range 10-70 micrograms.     

Determination of N1-methylnicotinamide in urine by high-pressure liquid chromatography.

This paper reports a precise method that is shorter than previously reported methods for the quantitative determination of N1-methylnicotinamide (MNA) in urine. The method employs a single column chromatographic isolation step, followed by high-pressure liquid chromatographic (HPLC) analysis. Potential interfering substances present in urine are removed during the column chromatography step. The combined MNA fractions eluted from this column were collected and concentrated for quantitative assay of MNA by HPLC. HPLC analysis was effected in less than 15 min using a strong cation- exchange column eluted with 0.25 M ammonium dihydrogen phosphate (pH 4.3). Linearity of MNA detection by HPLC at 254 nm extended below 20 ng, with an average recovery of 101% for 150, 250 and 500 microgram MNA added to 5 ml or urine.     

Processing impact on tocopherols and triglycerides composition of soybean oil and its deodorizer distillate evaluated by high-performance liquid chromatography

In the present study, high-performance liquid chromatography (HPLC) was used for the separation of tocopherols and triglycerides of processed soybean oil and deodorizer distillate (DD). The results of normal and reversed-phase modes of HPLC revealed that concentrations of tocopherols and triglycerides content were decreased during the neutralization, bleaching, and deodorization processes. The loss of individual tocopherols ranged between 55.16% and 63.25%. During processing, triglycerides containing stearic-oleic-linoleic (SOL) moieties and palmitic-palmitic-linoleic (PPL) fragments showed greater reduction up to 38.14% and 37.69%, respectively. Among tocopherols and triglycerides; γ-tocopherol and oleic-oleic-oleic (OOO) were found to be in greater concentrations 5.53% and 19.78%, respectively in DD as compared to their counterparts. A maximum reduction of tocopherols was observed in the deodorization step. DD was found to be a rich source of bioactive components; therefore, it could be used for many industrial applications including pharmaceutical formulations, cosmetics, and food industries.     

Separation of nitroimidazoles by reversed-phase high-pressure liquid chromatography

A mixture of eight N-substituted and unsubstituted nitroimidazoles has been separated by high-pressure liquid chromatography with 5% ethanol as the eluent. Compounds with the same capacity ratios were selectively detected electrochemically by differential pulse polarography with a hanging mercury drop electrode. The HMDE detector had higher detection limits than the photometric detector set at 315 nm.     

高效液相色谱法测定保健食品中的大豆异黄酮

建立了一种测定保健食品中大豆异黄酮的高效液相色谱分析方法,该方法可以使常见的大豆异黄酮6种主要成分大豆甙、黄豆甙、染料木甙、大豆甙元、黄豆黄素、染料木素得以分离和检测。采用乙腈-磷酸水溶液(pH2.8)作流动相,梯度洗脱,Venusil MP-C18色谱柱(150 mm×4.6 mmi.d.,5μm),流速为1.0 mL/min,紫外检测器,检测波长254 nm。结果表明各组分线性关系良好,相关系数R2为0.9991~0.9998,加标回收率在87%~106.9%,相对标准偏差均小于2%。检出限0.25~0.48μg/mL,该方法可同时测定大豆异黄酮的6种成分。     

Very high-pressure capillary liquid chromatography assisted by voltage

Capillary liquid chromatography at moderately high pressures and capillary electrochromatography (CEC) have been combined to drive the mobile phase through capillary columns packed with small diameter particles. In a column packed with 1.5 microm nonporous particles, linear velocities near 3mm/s were observed when combining inlet pressures of 690 bar (10,000 psi) and an applied voltage of 25 kV. Optimum linear velocity for the column was achieved using a pressure-voltage combination of 350 bar (5000 psi) and 5 kV. Separation efficiencies at near optimum linear velocity agreed with those predicted by the van Deemter equation for liquid chromatography. Retention factors were observed to decrease under pressure-voltage combination as the voltage was increased; such a behavior has been attributed to Joule heating effects.     

毛细管气相色谱法测定菜籽油中脂肪酸组成

采用FFAP毛细管气相色谱法对菜籽油的各组分进行了定性和定量分析.结果表明菜籽油中至少含有从肉豆蔻酸(C140)至鲨油酸(C240)共15种脂肪酸甘油酯.四次平行分析显示各成分含量的标准偏差低于0.33%,绝对偏差不超过0.70%.