this research work was supported by the office of the national research council of thailand and the faculty of pharmacy , silpakorn university , nakhon pathom , thailand .
 eleven heavy metals in various products of moringa oleifera were analyzed to determine eleven heavy metals ( al , as , cd , cr , cu , fe , pb , mn , hg , ni , and zn ) using inductively coupled plasma - mass spectrometry . the products of m. oleifera were purchased in nakhon pathom , thailand . 
 all products were digested with nitric acid solution before determining the concentrations of heavy metals . 
 the recoveries of all heavy metals were found to be in the range of 99.89 - 103.05% . 
 several criteria such as linearity , limits of detection , limits of quantification , specificity , precision under repeatability conditions and intermediate precision reproducibility were evaluated . 
 results indicate that this method could be used in the laboratory for determination of eleven heavy metals in m. oleifera products with acceptable analytical performance . 
 the results of analysis showed that the highest concentrations of as , cr , hg , and mn were found in tea leaves while the highest concentrations of al , cd , cu , fe , ni , pb , and zn were found in leaf capsules . 
 continuous monitoring of heavy metals in m. oleifera products is crucial for consumer health . 
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