Organic Acid Profiling in Mushrooms

The concentration of the organic acids in mushroom extracts was determined using Waters Alliance 2695 Chromatograph with a Waters 2996 Photodiode Array Detector (Waters Corp., Milford, MA, USA). The following acids were evaluated: acetic, citric, formic, fumaric, lactic, maleic, malic, malonic, oxalic, succinic, and quinic acids. The mushroom extracts were dissolved in Mili-Q water (Millipore, Temecula, CA, USA). Separation was conducted using Waters Atlantis C18 column (250 mm × 4.6 mm × 5 μm) at a 220-nm wavelength. The following column conditions were used: mM KH₂PO₄ (adjusted to pH 2.5 with H₃PO₄) and MeOH as an eluent (95:5, v/v), and flow rate at 0.8 mL/min [41 (link)]. Studied acids were identified by the retention times of their peaks in a chromatogram and quantified by comparing the peak area with standards (Supelco Analytical, Bellefonte, PA, USA) at a known compound concentration, according to the corresponding standard curve.