Pneumatically assisted electrospray-ion mobility spectrometry for quantitative analysis of intact proteins

In this work, quantitative analysis of intact proteins using ion mobility spectrometry (IMS) is introduced. For this purpose a pneumatically assisted electrospray ionization source with a new design was constructed. Liquid and nebulizer gas flow rates were optimized to achieve the highest response. The pneumatically assisted electrospray-IMS was used for quantitative analysis of insulin, bovine serum albumin (BSA) and human serum albumin (HSA). The analysis of proteins demonstrated that sensitivity of the pneumatically assisted electrospray-IMS is two to three times higher than that of conventional electrospray ionization (ESI) coupled to IMS. The linear dynamic ranges for insulin, BSA and HSA were found to be 1–75, 5–100 and 2–100 μg mL−1 with detection limits of 0.3, 1 and 0.6 μg mL−1, respectively. The relative standard deviations (RSD) for five replicate measurements of insulin, BSA, and HSA at 25 μg mL−1 were recorded as 3, 4 and 1.5%, respectively. The proposed method can be considered as an alternative way for quantitative protein analysis.