| Oil-tea camellia seed oil is a unique kind of nutural woody plant oil in our country,it is rich in nutrients such as polyphenols. It was a kind of pure nutural high quality cooking oil advocated by the government and a kind of nutural healthy edible oil recommended by IFAO, which has the ruption of "Oriental olive oil". In this paper,carbon nanotubes (CNTs) were used as materials and we proposed a new determination of polyphenols in camellia oil by accumulation of CNTs. We aimed at overcoming the shortcomings and problems in the traditional determination and finding a more safe and efficient extraction and detection of polyphenols in camellia oil,then providing a new route for the following analysis and research of polyphenols.The main contents and results were as follows:1.Revealed the accumulation regularities of polyphenols by CNTs: the best absorption condition was the temperature of 10 ?,the velocity of 100r/min,2 hours and the materials/liquid ratio of 1 : 10( g : mL). In this condition, CNTs presented a good absorption against polyphenols: the absorption of gallic acid in water was between 91% and 99%, and for those polyphenols in methanol like gallic acid and ferulaic acid, the absorption was also more than 88%.2.Found the effective way of desorption: when CNTs was 0.5g, the best desorption was that at the temperature of 400C,20mL actone desorbed CNTs for 30 minutes with the addition of 150W ultrasonic, which repeated 3 times. In this condition, the desorption ratio reached 40.78%. Among the research, we found that the larger the diameter was, the better the desorption. What's more, purification of CNTs and the functional group -COOH that CNTs carried also had promoting effect on desorption,and the diameter of CNTs whose desorption was best was 20?30nm.3.Determined the compensate factor of the accumulation of polyphenols in camellia oil by CNTs: we determined the total phenolic content (TPC) of camellia oil sample,which was 28.084 mg/kg. In the best technological codition,the absorption ratio of polyphenols was 80.54% while the desorption was 61.13%. The compensate factor of the method was 2.032, and the calculational method of actual TPC of camellia oil was: TPCA= 2.032 · TPCD ( TPCD was the determination).4.The validation of the method: when the concentration of polyphenols in camellia oil was between 4.4 and 93.0 ? g/g, the absorbance of desorption solution presented a good linear relationship with the concentration of polyphenol in camellia oil, the equation was y=0.0007x+0.043 while the correlation coefficient R2 was 0.9351. The recoveries were between 87.99% and 110.95% with relative standard deviation (RSD, n=6) between 8.38% and 10.74%. The minimum determination limit of the method was 3.24 ? g/g. When we determined 4 camellia oil samples whose concentration of polyphenols were unknown, there's no significant difference between the results of this method and those of SPE( P>0.05). The results showed that the method which taken CNTs as adsorbent to analysis the polyphenol in camellia oil had the advantage of high stability and accuracy,which provided a new mode of polyphenol determination in camellia oil. |
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