Chemistry Forum

I want to find an analytical method for the determination of phytic acid. I need a method that eliminates interferences. I have found some HPLC methods, but they are all based on the reaction of phytic acid with iron(III) thiocyanate, which results in a decrease in color intensity. However, this method is not interference-free because phytic acid can also react with other ions.
Does anyone have any suggestions?"

https://www.sciencedirect.com/science/a ... 7005018945

This is an article where they used HPLC to analyze phytic acid. However, if I understand it correctly, they mixed phytic acid with ferric thiocyanate and then put the ferric thiocyanate on HPLC. Why? Why didn't they just take some of the supernatant and measure its absorbance? Do we get rid of any interferences at all? Thanks.

Thanks for sharing your insights! SAX-HPLC is a smart choice for separating phytic acid, especially in complex matrices. I agree that while the enzymatic method is simpler, it might not provide the accuracy needed in grain samples. If you can go the LC-MS route, you'll definitely enhance your results and reduce interference issues.

they’re mixing phytic acid with ferric thiocyanate first, then running it through HPLC. The reason they don’t just measure absorbance of the supernatant directly is probably because grain extracts are a mess of compounds. Phytic acid chelates the iron, reducing the thiocyanate’s color, but other ions (like Ca or Zn) in the grain can bind it too, throwing off a simple absorbance reading. HPLC separates the ferric thiocyanate complex from that noise, so you’re tracking just that signal instead of a jumbled mess. It’s not perfect, though—interferences aren’t fully gone since phytic acid still reacts with other metals before the column.block blast

I’d second jesse99’s SAX-HPLC idea for grain. It isolates phytic acid upfront with an anion-exchange column, and conductivity detection skips the metal reagent hassle. LC-MS is gold if you can swing it—cuts through the grain matrix like a knife. What’s your lab setup like? That might steer you better!