Quantitation of Total Folate in Whole Blood Using LC-MS/MS
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- 作者：Janel E. Owens ; Dirk M. Holstege ; and Andrew J. Clifford
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2005
- 出版时间：September 21, 2005
- 年：2005
- 卷：53
- 期：19
- 页码：7390 - 7394
- 全文大小：71K
- 年卷期：v.53,no.19(September 21, 2005)
- ISSN：1520-5118
文摘
An accurate method for measuring whole blood total folate using liquid chromatography with tandemmass spectrometry is described and compared to GC/MS and a chemiluminescence assay. Wholeblood from normal adults (n = 15) was fortified with a [13C6]para-aminobenzoic acid (pABA) internalstandard and treated with 12.1 N hydrochloric acid at 110 
C for 4 h to hydrolyze all folates to pABA.Contaminants in the hydrolysate were adsorbed onto a C18 SPE cartridge. The eluate containingthe folate catabolite pABA was partitioned into ethyl acetate and methylesterified with trimethylsilyldiazomethane. The methyl-pABA derivatives were quantified by positive-ion atmospheric pressurechemical ionization (APCI)LC-MS/MS. An isocratic mobile phase of acetonitrile-water (70:30) (v/v)on a C18 analytical column was used with a postcolumn reagent of 0.025% formic acid. The limit ofquantitation for folate was 56.6 nmol/L RBC, and the limit of detection was 22.6 nmol/L RBC. Folatelevels as determined by LC-MS/MS correlated well with the chemiluminescence assay and a GC/MS method. This new LC-MS/MS method provides enhanced sample throughput (n = 36 per day)as compared to GC/MS methods. LC-MS/MS will enable accurate measurements of red blood cell(RBC) folate in nutrition surveys and clinical trials.Keywords: Folate; erythrocyte; mass spectrometry; para-aminobenzoic acid
C for 4 h to hydrolyze all folates to pABA.Contaminants in the hydrolysate were adsorbed onto a C18 SPE cartridge. The eluate containingthe folate catabolite pABA was partitioned into ethyl acetate and methylesterified with trimethylsilyldiazomethane. The methyl-pABA derivatives were quantified by positive-ion atmospheric pressurechemical ionization (APCI)LC-MS/MS. An isocratic mobile phase of acetonitrile-water (70:30) (v/v)on a C18 analytical column was used with a postcolumn reagent of 0.025% formic acid. The limit ofquantitation for folate was 56.6 nmol/L RBC, and the limit of detection was 22.6 nmol/L RBC. Folatelevels as determined by LC-MS/MS correlated well with the chemiluminescence assay and a GC/MS method. This new LC-MS/MS method provides enhanced sample throughput (n = 36 per day)as compared to GC/MS methods. LC-MS/MS will enable accurate measurements of red blood cell(RBC) folate in nutrition surveys and clinical trials.Keywords: Folate; erythrocyte; mass spectrometry; para-aminobenzoic acid