what is the best solvent for folic acid

[yanti]

dear all,

i am so keen to know about what is the best solvent for folic acid for HPLC analysis.
Here i am doing validation of six water soluble vitamins (B1, B6, Nicotinamide, Folic Acid, Biotin and B2). i m using Methanol and phosphor buffer pH 5 (gradient elution) and yielding good selectivity. but when i started in linierity study i m facing very bad linierity of folic acid, it seems that folic acid was not stabil at the solvent condition.
maybe i should to inform that i m using methanol and phosphor buffer pH 5 (20:80) as solvent. and the solvent mixture having pH for about 5.5

regard
yanti

[Mark Tracy]

Folic acid has poor solubility in organic solvents. I have found dilute sodium bicarbonate to be the best solvent, and still it is only about 400 mg/L maximum solubility. It is also very light sensitive. You will need to make it fresh every couple of days, and store it in the refrigerator.

[syx]

there are many type of solvent for folic acid if you search in USP. the most general is the use of basic solution (e.g. 10% ammonium hydroxide solution in small portion) to enhance folic acid solubility.
you should use low actinic volumetric flask to reduce degradation rate by light.