Methods for detecting vitamin c by mass spectrometry

Abstract

Provided are methods for determining the amount of vitamin C in a sample using mass spectrometry. The methods generally involve ionizing vitamin C in a sample and detecting and quantifying the amount of the ion to determine the amount of vitamin C in the sample.

What which is claimed is: 
     
         1 . A method for determining an amount of ascorbic acid (vitamin C) in a sample, the method comprising:
 (i) ionizing vitamin C in the sample by electrospray ionization (ESI) to generate at least one vitamin C ion detectable by mass spectrometry;   (ii) determining the amount of the at least one vitamin C ion by tandem mass spectrometry;   wherein the amount of vitamin C in the sample is determined from the amount of vitamin C ion(s) from step (ii).   
     
     
         2 . The method of  claim 1 , wherein the ionizing is performed in positive ion mode. 
     
     
         3 . The method of  claim 1 , further comprising purifying vitamin C in the test sample prior to mass spectrometry. 
     
     
         4 . The method of  claim 3 , wherein the purifying comprises purifying with liquid chromatography. 
     
     
         5 . The method of  claim 4 , wherein the liquid chromatography comprises high performance liquid chromatography (HPLC). 
     
     
         6 . The method of  claim 1 , wherein the amount of vitamin C in the sample is determined using a calibration standard curve. 
     
     
         7 . The method of  claim 1 , wherein the ions are detected by multiple reaction monitoring (MRM). 
     
     
         8 . The method of  claim 1 , wherein the method has an extraction recovery of more than 80%. 
     
     
         9 . A method for determining an amount of ascorbic acid (vitamin C) in a sample, the method comprising:
 (i) purifying vitamin C in the test sample by liquid chromatography;   (ii) ionizing vitamin C in the sample by electrospray ionization (ESI) in positive ion mode to generate at least one vitamin C ion detectable by mass spectrometry;   (iii) determining the amount of the at least one vitamin C ion by tandem mass spectrometry;   wherein the amount of vitamin C in the sample is determined from the amount of vitamin C ion(s) from step (iii).   
     
     
         10 . The method of  claim 9 , wherein the liquid chromatography comprises high performance liquid chromatography (HPLC). 
     
     
         11 . The method of  claim 9 , wherein the amount of vitamin C in the sample is determined using a calibration standard curve. 
     
     
         12 . The method of  claim 9 , wherein the ions are detected by multiple reaction monitoring (MRM). 
     
     
         13 . The method of  claim 9 , wherein the method has an extraction recovery of more than 80%.