Comparison of various nano-differential mobility analysers (nDMAs) applying globular proteins

Figures & data

Table 1. Properties and operating parameters of the evaluated nDMAs.

Operating Conditions	GEMMA (TU Vienna/UCLA)	L-nDMA	PDMA	GEMMA prototype
Sheath gas flow through nano-DMA (L/m)	15/20	14	20	18
Aerosol flow to sheath gas flow ratio (%)	8.7/7.5	9.3	6.5	7.2
Polarity of the central electrode	Negative	Positive	Positive	Negative
Feasible working range in terms of size (nm)	3–65	2–200	0.7–50	3–65
Scan range applied (nm)	3–25	2–20	1–20	3–65
Number of channels across scan range	60	47	68	90
Voltage scan direction	Up	Down	Down	Up
Scan rate (sec/channel)	2	2	2	2
Applied detector	CPC	FC	FC	CPC

Figure 1. Operating scheme of a nDMA. HV–High Voltage–scanned from 0 to 10 kv during mobility analysis, R₁–Inner Radius of the central electrode, R₂–Outer Radius of the central electrode.

Figure 2. Size spectra of the protein ovalbumine obtained with two different nDMAs.

Figure 3. Count mean diameter (CMD) for the selected standard proteins obtained with the five different nDMAs plotted as a function of molecular mass of the proteins.