How should I reconstitute an NADPH standard?

Your protocol for Amplite® Colorimetric NADH and NADPH Assay Kit (Cat# 15272) calls for the NADPH standard to be reconstituted in PBS. However, kits from other companies instruct that the NADPH standard be reconstituted with DMSO. Which one is correct?

For Amplite® Colorimetric NADH and NADPH Assay Kit both solvents may be used to reconstitute an NADPH standard; however for best results we recommend using PBS. DMSO is a very powerful solvent and at concentrations > 1% (v/v) DMSO may interfere with the reaction being monitored. Compared to DMSO, PBS is less toxic with less stringent requirements making it a better solvent for reconstituting an NADPH standard.

When preparing the NADPH stock solution it is important to note that like the PBS buffer, the stock solution has no color. The NADPH reaction mixture has a very light pink color. When mixing these two together, the solution will become a little pinkish.