Development and Validation of an HPLC Method for Simultaneous Assay of MCI and MI in Shampoos Containing Plant Extracts

Table 4

Results of accuracy and precision.

Replicate number ()	MI				MCI
	Spiked amount of standard (μg)	Peak area	Recovery (%)	Mean recovery (MR), RSD (%)	Spiked amount of standard (μg)	Peak area	Recovery (%)	Mean recovery (MR), RSD (%)
First spiked level (approximately the lowest concentration of calibration curve)
1	1.74	18343	90.3	Repeatability (1–6): MR: 92.6%; RSD: 3.6%; Intermediate precision (1–9): MR: 91.9%; RSD: 3.7%	5.22	33042	91.3	Repeatability (1–6): MR: 92.2%; RSD: 5.2%; Intermediate precision (1–9): MR: 92.0%; RSD: 4.9%
2	1.74	17957	88.4		5.22	34758	96.1
3	1.74	18834	92.6		5.22	31895	88.1
4	1.74	19762	97.0		5.22	32630	90.2
5	1.74	18556	91.3		5.22	36114	99.8
6	1.74	19504	95.8		5.22	31775	87.8
7	1.74	17549	86.5		5.22	32675	90.3
8	1.74	18631	91.6		5.22	35117	97.1
9	1.74	19125	94.0		5.22	31626	87.4
Second spiked level (approximately the middle of concentration range of calibration curve)
1	3.40	40871	101.1	Repeatability (1–6): MR: 98.1%; RSD: 3.2%; Intermediate precision (1–9): MR: 97.1%; RSD: 3.5%	10.16	67223	95.5	Repeatability (1–6): MR: 94.6%; RSD: 2.7%; Intermediate precision (1–9): MR: 94.0%; RSD: 2.6%
2	3.40	39065	96.7		10.16	65024	92.4
3	3.40	41127	101.8		10.16	66309	94.2
4	3.40	40138	99.4		10.16	64117	91.1
5	3.40	38722	95.9		10.16	67854	96.4
6	3.40	37892	93.9		10.16	68973	98.0
7	3.40	38205	94.6		10.16	65459	93.0
8	3.40	37051	91.8		10.16	66715	94.8
9	3.40	39726	98.3		10.16	63814	90.6
Third spiked level (approximately 80% of highest concentration of calibration curve)
1	4.12	44788	91.3	Repeatability (1–6): MR: 93.3%; RSD: 2.5%; Intermediate precision (1–9): MR: 93.6%; RSD: 2.6%	12.20	81056	95.9	Repeatability (1–6): MR: 94.7%; RSD: 3.4%; Intermediate precision (1–9): MR: 94.4%; RSD: 2.8%
2	4.12	46205	94.2		12.20	79682	94.3
3	4.12	47631	97.1		12.20	83127	98.3
4	4.12	45176	92.1		12.20	76531	90.5
5	4.12	44507	90.8		12.20	82415	97.5
6	4.12	46348	94.5		12.20	77214	91.3
7	4.12	44501	90.8		12.20	78462	92.8
8	4.12	47638	97.1		12.20	80574	95.3
9	4.12	46152	94.1		12.20	79263	93.8

^∗Note. For each spiked level, replicate analysis from No. 1 to No. 6 was done in the same day and used to validate the repeatability of the method, replicate analysis No. 7 to No. 9 was done in another day, and all replicate analysis from No. 1 to No. 9 was used together to validate the intermediate precision of the method.