. Author manuscript; available in PMC: 2019 Mar 26.

Published in final edited form as: Analyst. 2018 Mar 26;143(7):1556–1559. doi: 10.1039/c8an00056e

Table 1.

Positive and Negative ion CCS values measured with FIA and DI stepped-field methods

Analyte	Positive Ions								Negative Ions

	[M+H]⁺ (Da)^a	FIA ^DTCCS_N2 (Å²)^b			DI ^DTCCS_N2(Å²)^c			% Diff^d	[M-H]⁻ (Da)^a	FIA ^DTCCS_N2 (Å²)^b			DI ^DTCCS_N2(Å²)^c			% Diff^d

		Avg.	σ	%RSD	Avg.	σ	%RSD			Avg.	σ	%RSD	Avg.	σ	%RSD

Acetaminophen	152.07	131.84	0.45	0.34	132.01	0.35	0.26	0.13	150.06	134.48	0.07	0.05	134.16	0.11	0.08	−0.24

Caffeine	195.09	141.68	0.16	0.11	141.27	0.25	0.18	−0.29	–	–	–	–	–	–	–	–

Sulfaguanidine	215.06	150.18	0.18	0.12	149.60	0.26	0.17	−0.39	213.04	149.51	0.10	0.07	149.41	0.14	0.09	−0.07

Sulfadimethoxine	311.08	170.57	0.21	0.12	170.16	0.20	0.12	−0.24	309.07	172.61	0.09	0.05	172.38	0.18	0.11	−0.13

Val-Tyr-Val	380.22	192.97	0.34	0.18	192.34	0.20	0.11	−0.33	378.20	194.52	0.12	0.06	194.64	0.15	0.08	0.06

Verapamil	455.29	208.66	0.46	0.22	208.74	0.38	0.18	0.04	–	–	–	–	–	–	–	–

Terfenadine	472.32	227.37	0.46	0.20	227.93	0.43	0.19	0.25	–	–	–	–	–	–	–	–

Leucine-Enkephalin	556.28	230.02	0.40	0.18	229.86	0.38	0.16	−0.07	554.26	223.81	0.12	0.06	224.26	0.16	0.07	0.20

Reserpine	609.28	251.69	0.39	0.15	252.18	0.54	0.22	0.20	607.27	266.22	0.20	0.07	266.49	0.25	0.09	0.10

The average (Avg.), standard deviation of the mean (σ), and percent relative standard deviation (%RSD) of CCS values reported for N = 18 measurements.

Exact mass of the protonated or deprotonated ion.

Flow injection analysis (FIA) CCS values.

Direct infusion (DI) CCS values.

Percent difference between average FIA and DI CCS values.