To prepare the 10 mM ACh standard solution, dissolve 245 mg acetylcholine
perchlorate in 100 mL of 20 mM phosphate buffer, pH 3.5 (including 25
mM Na2EDTA-2H2O). Please store this 10 mM ACh solution at 4 ºC. When
making dilutions for a standard curve, use the 20 mM phosphate buffer, pH
3.5 (including 25 mM Na2EDTA-2H2O). Be very careful to never inject a high
concentration (mM or μM). This will necessitate disassembling the injector
and possible other parts to thoroughly clean them.