Determination and analysis of 17 amino acids in Qaidam Chinese wolfberry

To establish a pre-column derivatization and reversed-phase high performance liquid chromatography( RP-HPLC)for the determination amino acids in Qaidam Chinese wolfberry. Contents of amino acids in Qaidam Chinese wolfberry from different habitats and different picking period were analyzed.2,4-dinitrofluorobenzene( DNFB) was the pre-column derivating reagent.The samples were analyzed on a Gemini-NX C18 column with gradient elution of 0.05 mol·L~（-1）sodium acetate solution( adjusted to p H6.4)(A) and 50% ACN(B).The detected wavelength was 360 nm.HPLC method was adopted and external method was used for calculating the content of sample. The linear ranges,precision,stability and repeatability were good.Recovery and RSD of the method were 90.28% ~102.85% and 1.02% ~4.76% respectively.There were the same kind of amino acids,but there were a certain differences in the content in Qaidam Chinese wolfberry from different habitats and different picking period,the average contents of amino acids was the highest in Qaidam Chinese wolfberry from Delingha,the total content of amino acids in Qaidam Chinese wolfberry in October was higher than others,the total content of amino acids was6.217% ~8.987%,the ratio of essential amino acids was 14.307% ~ 19.527%,the ratio of medicinal amino acids was63.632% ~71.409%,the ratio of flavor amino acids was 12.121% ~ 17.356%. The method was very accurate,sensitive and reliable to determine the contents of amino acids in Qaidam Chinese wolfberry. Differences of amino acids in Qaidam Chinese wolfberry from different habitats and different picking period may be caused by environmental factors,weather conditions,etc.In the process of development and utilization of Chinese wolfberry,we should choose the right.