Table 4. Summary of HPLC-DAD (Detection System I) Validation Data for the Quantification of NBOMe Halide Derivatives (2a–d) Using ACE C18-AR Column (150 × 4.6 mm² i.d., Particle Size: 5 μm), Mobile Phase: [5 mM Ammonium Formate + 100 mM KCl (pH 7.0): Acetonitrile 70:30% (v/v)], Flow Rate: 2.5 mL min^–1, Column Temperature: 60 °C, and Detector Wavelength (UV): 205 nm.

	drug of abuse
parameters	25F-NBOMe (2a)	25C-NBOMe (2b)	25B-NBOMe (2c)	25I-NBOMe (2d)
r2 a	0.999b	0.999c	0.999d	0.999e
af	–13.52	–29.79	–41.17	–34.88
bg	9.08	16.38	23.12	15.58
LOD (μg mL–1)h	4.56	5.90	5.14	6.65
Precision (% RSD, n = 6)
10 (μg mL–1)	0.70	0.98	1.14	0.51
20 (μg mL–1)	0.58	1.84	1.78	0.01
50 (μg mL–1)	1.26	1.42	1.00	0.28
100 (μg mL–1)	1.08	0.76	0.65	0.98
150 (μg mL–1)	0.49	0.31	0.38	0.82
200 (μg mL–1)	0.93	0.30	0.36	0.79
300 (μg mL–1)	0.27	0.40	0.47	0.58
System Suitability Parameters
tR ± SD (min)i (n = 6)	3.83 ± 0.02	5.96 ± 0.02	7.01 ± 0.03	9.45 ± 0.05
RRTj	0.41	0.63	0.74	1
k′k	5.18	8.61	10.31	14.24
N (plates)l	8000	8629	8967	8670
HETP (m)m	1.88 × 10–5	1.74 × 10–5	1.67 × 10–5	1.73 × 10–5
Rsn		9.97	3.82	6.95
Aso	0.85	0.82	0.85	0.94
αp		1.66	1.20	1.38

^ar²: coefficient of regression.

^by = 9.08x – 13.52.

^cy = 16.38x – 29.79.

^dy = 23.12x – 41.17.

^ey = 15.58x – 34.88.

^fa: intercept of the regression line of the calibration curve.

^gb: slope of the regression line of the calibration curve.

^hLOD: limit of detection using the formula (3S_y/x)/b.

ⁱtR: retention time in minutes for drugs eluted from the chromatographic column (Detection System I).

^jRRT: relative retention time (determined with respect to 25I-NBOMe, 2d, retention time obtained from Detection System I).

^kk′: capacity factor.

^lN: number of theoretical plates expressed in plates per meter.

^mHETP: height equivalent to the theoretical plate expressed in meter.

ⁿR_s: resolution between two successive eluted peaks.

^oA_s: asymmetry factor.

^pα: relative retention factor.