Determination of Retinol, 𝛼-Tocopherol, Lycopene, and 𝛽-Carotene in Human Plasma Using HPLC with UV-Vis Detection: Application to a Clinical Study

Table 2

Average parameters of 10 calibration curves for the HPLC method.

Standard	Regression equation	Mean slope; 95% confidence interval	Intercept (𝜇mol/L)^2; 95% confidence interval	Correlation coefficient
Retinol^1	𝑦=0.4876𝑥+0.0164	0.4876 (0.4528–0.5221)	−0.03 (−0.06–0.01)	0.9997
𝛼-Tocopherol^1	𝑦=0.0375𝑥−0.0011	0.0375 (0.0342–0.0402)	0.03 (−0.21–0.26)	0.9998
Lycopene^1	𝑦=1.3854𝑥+0.0020	1.3854 (1.2731–1.4001)	−0.001 (−0.005–0.003)	0.9983
𝛽-Carotene^1	𝑦=2.8394𝑥+0.0057	2.8394 (2.5978–3.0826)	−0.002 (−0.007–0.002)	0.9996

¹Nine-point for the determination of analytical parameters and seven-point for routine analysis. ²The 𝑥-intercept (in 𝜇mol/L) is the point at which the line crosses the 𝑥-axis (where the 𝑦 value equals 0).