Using activated charcoal to remove substances interfering with the colorimetric assay of inorganic phosphate in plant extracts

Abstract Aim Organic substances in leaves of several southwest Australian native species interfere with sensitive colorimetric assays and prevent quantification inorganic phosphate concentration ([Pi]). We aimed to develop a reproducible routine procedure for treating leaf extracts activated charcoal (AC) remove interfering substances, allowing the determination [Pi] by malachite green spectrophotometric assay. Methods Leaf plants from Australia 1% ( v / ) acetic acid were treated 10 mg mL −1 acid-washed AC removal substances. Standard solutions (0 18 μM Pi) without treatment compared quantify Pi loss. A spiking recovery test was performed validate treatment. Results exhibited distinguishable absorbance peaks green-orthophosphate complex between 630 650 nm, as opposed untreated samples. The Pi-adsorption represented relatively larger fraction at 0–4 range stabilised higher when maximum adsorption capacity reached 11.7 μg g AC. after spiked samples ranged 100 111%. Conclusion successfully removed but caused Thus, AC-treated requires sample ≥ 6 use standards. error minor environmental variability [Pi]. time- cost-effective method extracts.