Rapid determination of 1-deoxynojirimycin in Morus alba L. leaves by direct analysis in real time (DART) mass spectrometry

Abstract

A new method based on a Direct Analysis in Real Time (DART) ionization source coupled with triple quadrupole tandem mass spectrometry has been developed for rapid qualitative and quantitative analyses of 1-deoxynojirimycin (DNJ) in mulberry leaves. Two ions produced from DNJ, [M+H]+ (m/z 164) and [M-2H+H]+ (m/z 162), are observed using DART–MS in the positive ion mode. The peak areas of the two selected ions monitoring (SIM) signals of ([M+H]+ (m/z 164) and [M-2H+H]+ (m/z 162)) are integrated to determine the peak area for quantitative analyses. A reasonable linear regression equation is obtained in the range of 1.01 to 40.50μg/mL, with a linear coefficient (R2) of 0.996. The limits of detection (LOD) and quantification (LOQ) of the method are 0.25 and 0.80μg/mL, respectively. The range of recovery is shown to be 87.73–95.61%. The results derived from the developed DART–MS method are in good agreement with those from the conventional HPLC–FLD method. By contrast, DART–MS in SIM mode is a simple, rapid and high-throughput approach for the determination of the DNJ content in mulberry leaves. The present method is advantageous for the rapid screening of mulberry leaves containing high DNJ contents.