Table 3. Precision and accuracy data for the determination of natural food preservatives in spiked cheese

Compound	Spiked concentration (μg/mL)	Detected concentration (μg/mL)	Recovery (%)	Intra-day test (n=3, RSD%)	Inter-day test (n=9, RSD%)
Benzoic acid	4.00	3.81±0.08	95.35±1.99	2.09	3.19
	2.00	1.97±0.04	98.60±1.79	1.82	1.97
	1.00	1.00±0.04	99.83±3.99	4.02	2.66
Sorbic acid	5.00	5.06±0.04	101.14±0.80	0.78	3.46
	2.50	2.55±0.15	101.96±4.64	4.44	6.26
	1.25	1.27±0.07	97.84±5.03	3.77	7.78
Propionic acid	40.00	37.12±0.82	92.80±2.04	2.28	3.60
	20.00	19.24±0.79	96.22±3.97	4.43	6.39
	10.00	9.96±0.46	99.56±3.75	5.31	5.78
Nitrate	10.00	9.43±1.63	94.27±1.04	1.12	9.53
	5.00	4.78±0.86	95.22±1.89	2.00	8.89
	2.50	2.51±0.45	95.07±4.58	5.29	3.60