. 2016 Sep 7;6:32637. doi: 10.1038/srep32637

Table 3. Inter- and intra-day reproducibility of the detection using urine sampled spiked with a 2 ng·mL⁻¹ clenbuterol.

Analysis^a	Measurements	Amount detected^b (ng·mL⁻¹)	Average SERS peak intensityI₁₄₇₄^a (counts)	RSD^b (%)	Overall RSD^c (%)
Intra-day	Day 1	1.89 ± 0.09	88.31	4.7	2.89
	Day 1	1.95 ± 0.08	92.38	4.0
	Day 1	1.97 ± 0.12	93.24	6.0
	Day 1	2.02 ± 0.20	94.09	9.4
	Day 1	1.94 ± 0.10	91.27	4.7
Inter-day	Day 1	1.92 ± 0.10	90.10	5.2	6.41
	Day 2	1.88 ± 0.09	88.01	4.6
	Day 3	1.90 ± 0.07	89.90	3.6
	Day 4	1.81 ± 0.07	78.04	3.7
	Day 5	2.09 ± 0.15	95.20	7.1

^aAverage of three determinations for each measurement.

^bRelative standard deviation (RSD (%) = (SD/mean) × 100) of individual measurements or days.

^cRSD % of inter- and intraday measurements.

Table 3. Inter- and intra-day reproducibility of the detection using urine sampled spiked with a 2 ng·mL−1 clenbuterol.