for qualitative measurementsOxalic acid (2% w/v in DMF). 2 mL Fumaric acid (2% w/v in DMF) . 2 mL Malonic acid (2% w/v in DMF) . 2 mL Phthalic acid (2% w/v in DMF) . 2 mLSuccinic acid (2% w/v in DMF) . 2 mLIsophthalic acid (2% w/v in DMF). 2 mL Glutaric a