Development of the Miniature NMR Apparatus for Edible Oil Quality Control

Edible oils are necessary in daily cooking; therefore, it is significantly important to find an efficient scheme for its quality control. In this work, a miniature nuclear magnetic resonance (NMR) apparatus was set up for the identification of edible oils with different qualities. Experimental results show that the total transverse relaxation time of the commercial refined edible oil is shorter than the poor quality edible oil. Further data processing was performed with inverse Laplace transformation for transverse relaxation time distribution analysis. The spectra of the distribution of transverse relaxation times of different qualities edible oils are also significantly different, among which, the refined edible oil has two peaks whereas the poor quality edible oil has three peaks. The experimental results are well agreed with the theoretical analysis. As the miniature NMR apparatus was employed to analyze three suspected illegal cooking oils which were seized at the scene of inspection, the three oils were all confirmed to be poor quality edible oils. The apparatus can also detect refined edible oils adulterated with illegal cooking oils. In conclusion, the presented miniature NMR apparatus could be a potential tool for edible oil quality control.