Micro‐method to determine iron concentrations in plant tissues using 2,2′ bipyridine

Research often needs to determine iron (Fe) concentrations in plant tissue samples. Current established methods depend on equipment and often require skilled laboratory staff, large sample sizes, and are relatively slow and expensive. We propose an efficient and fast method for measuring Fe concentrations of small rice samples via a microplate reader using sodium dithionite (SDT) as reducing agent and dipyridyl (DPD) as coloring agent. The results show that the method yields results comparable to ICP‐OES measurements which were used as standard method. Different concentrations of the chemicals used were tested for extraction, reducing power, and coloring efficiency, to optimize the method for the range of concentrations to be expected in rice under toxic Fe conditions. Best results were obtained using 500 mM SDT and 10 mM DPD, a sample size of 0.01g dry weight, and Fast Prep as extraction method. A linear calibration curve was obtained for 0 to 100 mg kg^?1 iron within the measured samples. The method proposed here was successfully applied to measure total Fe concentration in oven‐dried, milled plant samples. Applicability of the method for tissues other than rice and suboptimal extraction methods are discussed.