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Observation


The chromatographic profile of the sample was simple, showing cholesterol as the main component. Peak of cholesterol was identified using the solvent system [n-Hexane: Diethyl ether: MeOH:: 5:2:0.5 (v/v)] with the Rf value of 0.37 ± 0.01 and there was no overlap with any other analyses of the sample at 200 nm (Fig.1).



Fig. 1: 3D display of cholesterol peaks


The linearity of the proposed method was confirmed in the range of 100-700 ng of standard cholesterol. A linear regression of the data points for standard cholesterol is resulted in a calibration curve with the equation Y=644.436 + 652.7908x [regression coefficient (r2) = 0.99831, standard deviation (S.D.) = 2.13%] (Fig. 2). Cholesterol content in edible oils was found to be in the range of 150-710 ng/spot selected for study (Table 1).



Fig. 2: Calibration curve of cholesterol



Table1: Cholesterol levels in edible oils

Edible oils Cholesterol content [ng/spot ± S.D %]
Coconut 150 ± 2.13
Mustard 280 ± 2.13
Taramira 320 ± 2.13
Soyabean 420 ± 2.13
Sunflower 560 ± 2.13
Peanut 710 ± 2.13


The linearity, accuracy in terms of recovery % and precision was considered for the method. Validation of the method at three concentration levels was carried out by the standard recovery formula [9] returned a mean of 90.66%. Precision (repeatability) was determined by running a minimum of four analyses and the coefficient of variability was found to be 1.662 %. The limit of detection (LOD) and quantification (LOQ) was found to be 10 and 32 ng respectively.