Reversed-phase HPLC/EC determination of folate in citrus juice by direct injection with column switching

Capillary Electrophoresis and High-Performance Liquid Chromatography Determination of Polyglutamyl 5-Methyltetrahydrofolate Forms in Citrus Products

“…NFC GJ. The NFC GJ folate results confirm previous findings (1,10,15,16). The folate was found to be ∼0.2 nmol/mL, ∼80% less than a typical NFC OJ sample (∼1 nmol/mL) (Figure 4).…”

“…NFC OJ folate amounts ranged between 0.6 and 1.4 nmol/mL throughout the study, indicating that folate amount may vary with individual fruit as well as maturity, cultivar, growth conditions, processing, etc. The literature has shown similar variability in folate amount (1,10,11,(14)(15)(16). It was noted that most NFC OJ samples analyzed within this study contained ∼1 nmol/mL, which was similar to previous findings (1,(14)(15)(16).…”

“…Previous studies of OJ folate by conventional chromatography (11) and by HPLC (14)(15)(16) showed no evidence of other folate forms at significant concentrations. Two recent papers have reported that folic acid (i.e., pteroylglutamic acid) is present in low and variable proportions in OJ (17,18).…”

Principles of Food Chemistry

“…Citrus fruit and juices are relatively good sources of folic acid, which is present mostly as the reduced 5-methyl tetrahydrofolate (monoglutamate form). There are also polyglutamate derivatives present (White et al 1991). …”

Capillary electrophoretic determination of methotrexate, leucovorin and folic acid in human urine

“…The most widely used are those based on gas chromatography or high-performance liquid chromatography (HPLC) with absortion [23][24][25][26][27][28], fluorescence [29][30][31][32] or phosphorescence [33] detection, together with bioassays [34,35] and voltamperometry [36,37].…”