. 2022 Jul 13;414(22):6571–6580. doi: 10.1007/s00216-022-04214-0

Table 1.

LC-ESI ( +)-MS/MS conditions for chlorhexidine and chlorhexidine-d₈, linearity, and instrumental LOQ

Compound	Retention time (min)	Precursor ion [M + 2H]²⁺	Cone voltage (V)	Q1 (CE, eV)	Q2 (CE, eV)	Q2/Q1 ratio	Other ions	Calibration curve (5–250 µg L⁻¹; n = 7 levels)	R²	LOQ (µg L⁻¹)
Chlorhexidine	4.9	253.1	40	170.0 (17)	125.1 (22)	0.45	153.0, 142.1	Slope: 0.0234 ± 0.0006 Intercept: − 0.0577 ± 0.0621	0.997	2
Chlorhexidine-d₈	4.9	257.1	40	174.1 (17)	125.1 (22)	0.45	157.0 142.1

Compound

Retention time (min)

Precursor ion [M + 2H]²⁺

Cone voltage (V)

Q1 (CE, eV)

Q2 (CE, eV)

Q2/Q1 ratio

Other ions

Calibration curve (5–250 µg L⁻¹; n = 7 levels)

R²

LOQ (µg L⁻¹)

Chlorhexidine

4.9

253.1

170.0 (17)

125.1 (22)

0.45

153.0, 142.1

Slope: 0.0234 ± 0.0006

Intercept: − 0.0577 ± 0.0621

0.997

Chlorhexidine-d₈

4.9

257.1

174.1 (17)

125.1 (22)

0.45

157.0

142.1