Construction of a Gradient ${\mu}LC/MS$ system and Its Application

A gradient LC/MS system was constructed and applied for separation of biological samples. For example, a rapid and simple analytical method without pretreatment based on gradient ${\mu}LC/MS$ with a disposable microcolumn has been developed to determine B group vitamins in urine. Urine samples were directly injected to the disposable home-made microcolumn. The microcolumn can be emptied after being used for a series of urine samples, and repacked with fresh stationary phase. An overdose of vitamin pills were swallowed by healthy volunteers and the urine samples were taken 1,2,3,5, and 8 hours after swallowing. Vitamins immediately showed up in urine, hit the maximum, and disappeared swiftly. This technique is expected to have some application for clinical purposes.