Table 3.

Method performance parameters for measurement of NCHs. Flowrate 300 μL/min, 5 μL injection volume. Separation column: Primesep 200, Gradient according to ESM Table S3. MS condition according to ESM Table S4

Compound	Slope (sensitivity) (peak area × L/μg)	Intercept (peak area)	R2	Method standard deviation (μg/L)	Linear range (μg/L)	MDL (μg/L)
Imidazole	(69.8 ± 0.2) × 103	(− 1 ± 0.4) × 105	0.9999	1.55	1–500	6.11
Pyrazole	(81.7 ± 0.4) × 103	(− 2.2 ± 0.8) × 105	0.9998	2.44	1–500	3.62
Pyridine	(186.8 ± 0.8) × 103	(− 0.6 ± 0.1) × 105	0.9999	1.88	1–500	3.3
Pyridazine	(59.4 ± 0.8) × 103	(− 4.7 ± 1.6) × 105	0.9991	6	5–500	4.93
Piperidine	(174.1 ± 0.7) × 103	(− 4.7 ± 1.3) × 105	0.9999	1.93	1–500	2.74