| 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 μ 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 μ 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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