What Are Fat-Soluble Vitamins

First, mobile phase and column we saw that most of the small molecule separations could be made on a C18 column in An/buffer water, with the exception of charged molecules and carbohydrates, which are too water soluble. We saw a range of polarity from fat-soluble vitamins, steroids, triglycerides, chlorinated pesticides eluting in 60-80% An/water, to carbamate, phosphate pesticides, anticonvulsants, antidepressants at 40-50% An/water, to nucleosides, nucleotides, aspirin, and water-soluble vitamins at 5-10% An/water. If you know something about the compound s structure or its solubility, you have a good clue as to what mobile phase can be used for its separation. 

Vitamins function in two basic ways, either as a nutrient or vitamin or as a chemical (Herbert, 1980). When the function is known, fat-soluble vitamins function as regulators of specific metabolic activity, and the water-soluble vitamins function as coenzymes. Although rather exact roles for some of the vitamins in the chain of metabolic events are understood, it is safe to say that the complete function of any one of the vitamins in the body is unknown. What we do know about specific coenzyme functions is that the encouragement of doses of at least tenfold above the recommended dietary allowance (RDA) serves no nutritional function (Herbert, 1977). Vitamins enter the body as a component of food, travel to the tissues/cells that need them, are taken into the cells, and converted into a coenzyme form. In some cases the vitamin enters the cell as the coenzyme form already. A protein within the cell, called apoenzyme, combines with the vitamin coenzyme to form a holoenzyme. The holoenzyme or enzyme then serves the vitamin function of catalyzing certain specific metabolic-biochemical reactions. It appears that only when combined with its apoenzyme within the cell can a vitamin function as a vitamin. Since the quantity of protein, as well as the quantity of apoenzyme, any cell can make per unit time is limited (Schimke and Doyle,... 

Space-filling diagrams for the stmctures of vitamin A, vitamin D, and vitamin C are shown below. Which are fat-soluble Which are water-soluble What is the difference between the stmctures of water-soluble and fat-soluble vitamins ... 

What are the fat-soluble and water-soluble vitamins For which class of vitamins is overconsumption a bigger problem Why ... 

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