Determination of Dhurrin Content in Different Parts of Macadamia

HPLC-ELSD internal standard method was explored for the determination of dhurrin content in macadamia nuts,flowers,leaves,shells and husks to lay the foundation for the further application of macadamia. Amygdalin was chosen as the internal standard object in the experiment. Analysis was carried out using HPLC,equipped with an Diamonsil C₁₈ column(150 mm×4.6 mm,5 μm)thermostated at 35℃. Chromatography was performed with the injection volume of 5 μL and total flow rate of 1.0 mL/min,by eluting with a gradient of acetonitrile(A)and 0.1% formic acid water solution(B). ELSD detector was used for dhurrin detection. Results showed that the standard curve for the concentration ratio(X)of dhurrin and amygdalin and their corresponding peak area ratio(Y)was Y=0.465389X²+0.349685X-0.000520968,with a fit of R²=0.9977,RSD was 2.60%.Recovery rate of this method was 97.93±2.35%,RSD=2.39%. Dhurrin content in macadamia flowers was the highest(49.92±0.96) mg/g,followed by macadamia leaves,and the lowest dhurrin content was found in macadmaia nuts(0.64±0.01) mg/g.Besides,dhurrin contents in different cultivars of macadamia husks was also varied. HPLC-ELSD internal standard method is a rapid,simple,accurate and reproducible method for dhurrin determination,with relatively low cost and reliable quantitative results. Appropriate consideration should be given to the removal of dhurrin in macadamia flowers and leaves before using due to their relatively high level of dhurrin content. While macadamia nuts contain only trace amounts of dhurrin,which is safe to use.