Development and Validation of a Method for the Analysis of Zinc Oxide in Cosmetic Matrices by Flame Atomic Absorption Spectroscopy

Table 2

Linearity and sensitivity parameters for all cosmetic matrices.

		Raw material	Lipstick	Emulsion	Foundation
Linear range	Slope	0.3502	0.2694	0.2539	0.2635
	r^2	0.9979	0.9992	0.9989	0.9985
	t value^a	128.2	204.2	177.7	152.5
	F value^b/10^4	1.64	4.17	3.16	2.33
Sensitivity	LOD (mg·L^−1)	0.0156	0.0098	0.0113	0.0131
	LOQ (mg·L^−1)	0.0473	0.0297	0.0341	0.0397
	(i) %RSD	2.97	2.46	2.01	1.95
	(ii) %recovery	99.4	99.5	99.9	101.1
	(iii) t value^a	0.509	0.492	0.122	1.41

^at critical value (0.05 significance level): 2.032 (linearity) and 2.571 (LOQ). ^bF critical value (0.05 significance level): 4.1366.