Figure 3: Bioanalytical tests for the parameters of molecular identity and structure. Advantages (in green), disadvantages (in red) and “neutral” criteria (in black) on the basis of the criteria for target qualification are given for mass spectrometry (nano-electrospray, MALDI-TOF, LC-MS/MS, 200 μM, 22°C, pH = 4.0, Zn2+, Cl-) and native gel electrophoresis (polyacrylamide gel, urea, 20 μg, pH = 6.8) combined with immunoblotting (polyclonal anti-insulin antiserum, 16 h) as exemplified for some insulin variants (symbols see Figure 1). Some alternative methods are listed at the bottom.