Determination of Very Low Level of Free Formaldehyde in Liquid Detergents and Cosmetic Products Using Photoluminescence Method

Table 5

Recoveries of formaldehyde in dishwashing liquid 1 and hair shampoo 1 samples with confidence limit 95%.

Sample	Added formaldehyde (µg·Kg^−1)	Found formaldehyde (µg·Kg^−1)	Expected formaldehyde (µg·Kg^−1)	Recovery factor; %	Relative errors; %
Dishwashing 1 liquid	0	5.83 ± 0.2	—	—	—
	3	8.62 ± 0.4	8.83	97.62	−2.37
	5	11.13 ± 0.3	10.83	102.77	2.77
	8	13.48 ± 0.5	13.83	97.46	−2.53
Hair shampoo 1	0	4.88 ± 0.3	—	—	—
	3	8.26 ± 0.2	7.88	104.82	4.82
	5	9.50 ± 0.4	9.88	96.15	−3.84
	8	12.42 ± 0.6	12.88	96.42	−3.57

All values are means ().