Quantification of Caffeoylquinic Acids in Coffee Brews by HPLC-DAD

Table 3

Intraday precision and recovery of CQAs in coffee brews, spiked at two different concentration levels.

Spiked level^a	Analyte	Initial; concentration; (mg/L)	Precision (%CV)	Recovery (%)
Filter coffee (prepared from roasted and ground Arabica coffee)
C1	3-CQA	307.86	1.50	92.71
	4-CQA	169.72	1.59	98.32
	5-CQA	161.00	1.82	96.91
C2	3-CQA	307.86	1.96	90.38
	4-CQA	169.72	0.86	97.09
	5-CQA	161.00	1.03	97.10
Instant natural A
C1	3-CQA	62.51	1.77	98.81
	4-CQA	51.26	1.58	100.64
	5-CQA	65.38	1.88	97.06
C2	3-CQA	62.51	1.08	91.46
	4-CQA	51.26	2.00	94.80
	5-CQA	65.38	0.53	93.90
Capsule coffee (A—type 5)
C1	3-CQA	369.27	2.21	101.89
	4-CQA	234.95	2.17	102.51
	5-CQA	222.08	2.24	100.00
C2	3-CQA	369.27	1.57	99.83
	4-CQA	234.95	1.65	101.31
	5-CQA	222.08	1.74	103.39

Spiked samples were prepared at two concentrations levels as follows. C1: 3-CQA (80 mg/L), 4-CQA (40 mg/L), and 5-CQA (40 mg/L); C2: 3-CQA (240 mg/L), 4-CQA (120 mg/L), and 5-CQA (120 mg/L).