Table 5.

Robustness data for ferulic acid analysis (n = 3).

Parameter	Drug content (%) ± SD∗	RSD∗∗	Retention time (min)
Flow rate (mL/min)
0.9	102.71 ± 1.93	1.88	5.39
1.0	100.12 ± 0.60	0.60	4.86
1.1	99.78 ± 0.57	0.57	4.49
pH of mobile phase
3.0	100.12 ± 0.60	0.60	4.86
4.0	97.56 ± 0.98	1.00	4.80
6.0	98.03 ± 0.37	0.38	4.52
Temperature (°C)
Ambient	100.12 ± 0.60	0.60	4.86
30	100.09 ± 1.09	1.09	4.71
40	99.14 ± 2.22	2.24	4.44

^∗SD = standard deviation; ^∗∗RSD = relative standard deviation.