Trace Element Content of Senna Study Material and Selected Senna-Based Dietary Supplements as Determined by Inductively Coupled Plasma-Optical Emission Spectrometry and Inductively Coupled Plasma-Mass Spectrometry

Abstract

The efficacy of senna laxative products and the worldwide trend towards self-medication with dietary supplements of a natural origin have fueled several investigations into the potential health effects associated with their use. The goal of this work was to determine the trace element content [aluminum (Al), arsenic (As), barium (Ba), calcium (Ca), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), sodium (Na), lead (Pb), strontium (Sr), vanadium (V), and zinc (Zn)] of a bulk senna sample that was procured for use as a study material in one such investigation. In addition, seven commercially available senna-based dietary supplements were purchased and analyzed along with the study material. Samples were digested using high-purity acids and oxidants and were analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS). Differences between the trace element content of the analyzed products were observed. Lead was detected in three of the tested samples (ranging from 0.686 to 1.12 μg g−1), and arsenic was detected in seven samples (ranging from 0.063 to 0.280 μg g−1). Recovery data for fortified control samples and standard reference materials (NIST 1573a Tomato Leaves, NIST 1547 Peach Leaves) indicated accurate and precise method performance.