Modern procedures for the analysis of tocopherols

Abstract

The development of reliable assay methodology for the tocopherols has been an evolutionary process which has required over 40 years to reach its present state. Today the analyst has at his disposal a choice of reliable and accurate methods of analysis for the eight tocopherols now known to exist in nature. The general sequence of procedure and the precautions to be observed are described. After suitable extraction procedures and careful saponification techniques, the tocopherols in the nonsaponifiable fraction can be assayed by a variety of chromatographic procedures including paper, thin layer (TLC), column and gas liquid chromatography (GLC). The current methodology of these procedures is reviewed in some detail with special emphasis on the more frequently used TLC and GLC techniques. The earlier methods of GLC assay separated only the mono‐, di‐ and trimethylated tocopherols but methods are now available which provide separation of all the tocopherols. These developments were made possible by better columns and the use of derivatives of tocopherols. In addition to good separation, the GLC method is the most sensitive available for the quantitation of the tocopherols. Spectrophotometric measurements based on Emmerie Engel type reactions have been most frequently used for the final quantitative analysis of the tocopherols separated by paper, TLC, or column chromatography.

Separation of Individual Tocopherols from Soybean Distillate by Low Pressure Column Chromatography

“…Other non-alpha T are usually separated by chromatographic methods such as thin-layer chromatography (TLC) [9][10][11], high-performance liquid chromatography (HPLC) [12][13][14][15] etc. Abidi [16] and Ruperez [17] reviewed the published chromatographic methods for separation and purification of individual tocopherols.…”

Vitamin E content of feedstuffs determined by high-performance liquid chromatographic fluorescence

“…Other significant contributors to vitamin E analytical methodology include Lovelady (1973), Tangney et al (1978), and Slover (1971). Bunnell (1971) provides a thorough review of the development of analytical procedures for vitamin E.…”