Table 1.

Linear regression data, LOD, and LOQ of the standard compounds.

Standard analytes	Linear regression data			LOD (μg/mL)	LOQ (μg/mL)
	Regressive equation	Test range (μg/mL)	R 2
Oxalic acid	Y = 5.67e + 003X − 9.61e + 003	4-1000	0.9997	1.71	6.53
Maleic acid	Y = 6.00e + 004X + 1.04e + 004	0.4-200	0.9991	0.05	0.10
Citric acid	Y = 5.99e + 002X − 5.25e + 003	10-2000	0.9998	3.23	12.93
Tartaric acid	Y = 9.89e + 002X − 2.47e + 003	10-2000	0.9999	3.36	7.73
Malic acid	Y = 4.80e + 002X − 4.96e + 003	10-2000	0.9999	3.53	14.13
Quinic acid	Y = 2.99e + 002X − 3.446e + 003	10-2000	0.9999	10.63	18.97
Succinic acid	Y = 3.37e + 002X − 2.82e + 003	10-2000	0.9999	8.31	15.82
Fumaric acid	Y = 4.60e + 004X − 5.53e + 003	0.4-200	0.9999	0.07	0.20
Formic acid	Y = 7.11e + 002X − 6.16e + 003	10-1000	0.9999	5.13	14.57
Acetic acid	Y = 3.51e + 002 X + 2.90e + 002	10-1000	0.9999	4.89	9.77
Propionic acid	Y = 3.46e + 002X − 2.00e + 003	10-1000	0.9999	4.89	12.06
Isobutyric acid	Y = 3.79e + 002X − 2.10e + 003	10-1000	0.9999	9.43	19.53
Butyric acid	Y = 3.23e + 002X − 9.69e + 002	10-1000	0.9999	4.75	9.63