A Novel HPLC Method for the Concurrent Analysis and Quantitation of Seven Water-Soluble Vitamins in Biological Fluids (Plasma and Urine): A Validation Study and Application

Table 4

Regression parameters of analysed vitamins. Regression parameters (regression equation [±SD of slope and intercept] and regression coefficient) and detection limits (signal-to-noise ratio = 5 and injection volume = 3 μL).

Vitamin	Limit of detection [ng μL^−1] at given UV (λ, [nm])	Regression line	Regression coefficient
C	0.5 ng μL^−1 (230 nm)	𝑦=0.657(±0.003)𝑥+127.1(±0.002)	𝑅^2=0.994
B1	1 ng μL^−1 (270 nm)	𝑦=8.789(±0.002)𝑥+16.31(±0.004)	𝑅^2=0.996
B2	0.5 ng μL^−1 (265 nm)	𝑦=301.7(±0.005)𝑥+467.3(±0.002)	𝑅^2=0.996
B5	1 ng μL^−1 (266 nm)	𝑦=1.052(±0.008)𝑥+66.43(±0.003)	𝑅^2=0.979
B6 (PLP)	0.5 ng μL^−1 (257 nm)	𝑦=7.451(±0.003)𝑥+12.81(±0.004)	𝑅^2=0.997
B9	1 ng μL^−1 (280 nm)	𝑦=246.1(±0.002)𝑥+54.31(±0.005)	𝑅^2=0.999
B12	2 ng μL^−1 (230 nm)	𝑦=132.9(±0.007)𝑥+209.6(±0.008)	𝑅^2=0.995