A rapid method for the determination of vitamin E forms in tissues and diet by high‐performance liquid chromatography using a normal‐phase diol column

Abstract

This paper describes a simple method for the analysis of tocopherols in tissues by which frozen tissues-70 degrees C were pulverized at dry ice temperatures (-70 degrees C) and immediately extracted with hexane. There was no need to remove the coeluting lipids from tissues by saponification, since at that level of neutral lipids in the sample, there was no reduction in fluorescence response. For the analysis of oil, in which large amounts of neutral lipids were coextracted, a 20% reduction of fluorescence response was observed, but the response was equal for all tocopherol forms, and was appropriately corrected. Saponification was used only when tocopherol esters were present, and only after an initial hexane extraction to remove the free tocopherols in order to avoid their loss by saponification, particularly non alpha-tocopherol and tocotrienols. All the tocopherols and tocotrienols were separated on a normal-phase diol (epoxide) column that gave consistent and reproducible results, without the disadvantages of nonreproducibility with silica columns, or the lack of separation with reversed-phase columns. The tocopherols were quantitated by using a tocopherol form not present in the sample as an internal tocopherol standard, or using an external tocopherol standard if all forms were present, or when the sample was saponified. Piglet heart and liver samples showed the presence of mainly alpha-tocopherol, with minor amounts of beta- and gamma-tocopherol and alpha-tocotrienol, but no delta-tocopherol. Only small amounts of tocopherol esters were present in the liver but not in the heart.

Simple Extraction and Rapid HPLC Method for Tocopherol Analysis in Marine and Fresh-water Fish Species

“…Bhadra et al (2004) found only α-tocopherol in sardine, sea bream, horse mackerel and flat fish species and reported that the highest α-tocopherol content was observed for sardine (16 mg/kg). Higher tocopherol results found in this study, as reported by Kramer et al (1997) may reflect the success of used method to recover more of the tocopherols from tissues.…”

“…Extraction of tocopherols and tocotrienols before quantification by HPLC, depending on the sample, is usually performed by direct solvent extraction or saponification (alkali hydrolysis) (Eitenmiller and Lee, 2004). Although several HPLC methods for tocopherol analysis have been reported, they have been applied to aquatic organisms and fish feed (Huo et al, 1999), European catfish muscle (Ng et al, 2004), microalgae (Huo et al, 1997), and liver and heart tissues of piglets (Kramer et al, 1997). It is thus necessary to develop a method that is convenient, a simple, less time-consuming, accurate and practical enough for tocopherol analysis for seafood.…”

Fermentation of Barley by Using Saccharomyces cerevisiae : Examination of Barley as a Feedstock for Bioethanol Production and Value-Added Products

“…Samples were prepared for analysis using the method described by Panfili et al (24). Tocopherols and tocotrienols were analyzed by using high-pressure liquid chromatography as previously reported (16). The concentrations of ␣-, ␤-, ␥-, and ␦-tocotrienols were calculated by the use of the relative response factors for ␣-, ␤-, ␥-, and ␦-tocopherols (1.14, 0.62, 1.82, and 0.54, respectively).…”

Batch Extraction of Oil from Rice Bran with Liquefied Low Temperature Dimethyl Ether

“…For detection of tocopherols and tocotrienols in cereal oils, an excitation wavelength of 290-296 nm and an emission wavelength of 325-330 nm are commonly used [23][24][25]. However, in the fluorescence analysis, the fluorescence signal (fluorescence with UV-excited UV emission) corresponding to either tocopherols or tocotrienols in RBO was barely detectable in our assay model.…”