Study On The Determination Of 5 Kinds Of Vitamin A And D Components In Dietary Supplements Using Column-switching Technique

Inadequate intake of vitamins can cause vitamin deficiency and even cause a variety of diseases,but excessive intake will bring toxic side effects.Vitamin supplements which has nearly 2000 approval numbers is a majority part of dietary supplements and it is necessary to control and evaluate the quality of vitamin supplements.Nowadays,the determination of vitamin AD in dietary supplements is generally directly using the method of national standard(Food and dairy products)and no corresponding method which according to the characteristics of dietary supplements was established.The method of national standard needs complex sample preparations which including saponification and extraction.The determination of vitamin D also needs the normal phase preparative chromatography to purificate and the process is time-consuming which needs multiple transferation and dissolution.Vitamin AD are sensitive to light,heat,oxygen,so it is a big challenge for unskilled person.The accuracy and repeatability of vitamin AD can not be guaranteed,so the method is difficult to apply for routine testing.Microencapsulation of vitamins which could increase its stability and improve the bioavailability is becoming an advanced research hotspot.However,this new preparation technology brings new challenge to the detection.Therefore,a new method for the determination of vitamin AD in dietary supplements is extremely necessary.In this paper,we select proper sample treatment methods according to four different sample matrixs.Using column-switching technique,we establish a quick,accurate,sensitive method for the simultaneous determination of vitamin A,vitamin A acetate,vitamin A palmitate,vitamin D2 and vitamin D3 in dietary supplements.The chromatographic separation of analytes was performed on Agilent ZORBAX Eclipse Plus C18(3.0mm×150mm,3.5?m)as first dimensional column with flow rate at 0.6mL/min and Acclaim 120 PA ? C18(4.6mm × 150 mm,3?m)as second dimensional column with flow rate at 0.8mL/min;with methanol,acetonitrile and water as the mobile phase,gradient elution,the column temperature was 35?,the detection wavelength was 265 nm.5 kinds of vitamins can well separate from each other.The linear range of vitamin A?vitamin D2?vitamin D3?vitamin A acetate,vitamin A palmitate was 0.05?g/ml-20.04?g/ml,0.013?g/ml-1.30?g/ml,0.013?g/ml-1.30?g/ml,0.057?g/ml-22.84?g/ml,0.43?g/ml-43.30?g/ml,respectively,r=1.0000.RSD of method repeatability is 0.7%-3.1%(n=6).The average recovery is 93.5%-103.1% and the RSD is 1.9%-3.8%.The analysis result of vitamin AD has no significant difference between the new method and the national standard method and it can be used for the daily determination of vitamin AD in dietary supplements.We use the new method to determination vitamin AD preparations of different manufacturers and the results was good.During the determination of vitamin D,there exists the interfering components.We use column-switching technique to replace the normal phase preparative chromatography and it greatly improves the accuracy and the sensitivity of the method.The established HPLC method can analysis the source of cod liver oil preparations and vitamin AD preparations.It can distinguish vitamin A acetate and vitamin D3 of synthesis sources or cod liver oil of natural sources and it provides a reference method for the determination of vitamin AD preparations in drugs.