Table 4.

Robustness of the suggested technique using (50, 5.0, 5.0 and 10 μg/mL of PAR, LVC, PHN and AMB, respectively).

Parameter	Concentration found (µg/mL)				% Found
	PAR	LVC	PHN	AMB	PAR	LVC	PHN	AMB
Ethanol ratio, %
19	49.571	4.963	4.998	10.249	99.14	99.26	99.96	102.49
20	49.973	5.017	5.010	10.018	99.95	100.35	100.20	100.18
21	50.561	4.900	5.055	10.220	101.12	97.99	101.10	102.20
Mean					100.07	99.20	100.42	101.63
± S.D					1.00	1.18	0.60	1.26
%RSD					1.00	1.19	0.60	1.24
%Error					0.57	0.69	0.34	0.71
Acetonitrile ratio, %
4.5	48.953	5.081	4.926	9.903	97.91	101.61	98.52	99.03
5.0	49.973	5.017	5.010	10.018	99.95	100.35	100.20	100.18
5.5	50.190	5.139	5.080	10.128	100.38	102.77	101.60	101.28
Mean					99.41	101.58	100.10	100.17
± S.D					1.32	1.21	1.54	1.13
%RSD					1.33	1.19	1.54	1.12
%Error					0.77	0.69	0.89	0.65
pH
6.4	49.015	5.041	4.962	10.128	98.03	100.83	99.25	101.28
6.5	49.973	5.017	5.010	10.018	99.95	100.35	100.20	100.18
6.6	49.200	4.997	5.042	9.961	98.40	99.95	100.83	99.61
Mean					98.79	100.38	100.09	100.36
± S.D					1.02	0.44	0.80	0.85
%RSD					1.03	0.44	0.80	0.85
%Error					0.59	0.25	0.46	0.49