Determination of Total Arsenic and Speciation in Apple Juice by Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry: An Experiment for the Analytical Chemistry Laboratory.

A two-part laboratory experiment was designed for upper-level analytical chemistry students to provide handson experience in the use of high performance liquid chromatography (HPLC) for separation and inductively coupled plasma mass spectrometry (ICP-MS) for detection. In the first part of the experiment, the students analyze total arsenic in apple juice purchased from local grocery stores using direct injection ICP-MS. In the second part, different species of arsenic in the same apple juice samples are determined using HPLC ICP-MS. Quantification is performed based on two methods, standard addition and external calibration curve, to demonstrate how sample matrix can affect the accuracy of the analysis. The experiments provide the opportunity to introduce acid/or review several fundamental analytical chemistry concepts: chromatographic separations, mass spectrometry, inductively couple plasma, matrix effect's, calibration methods, internal standard, and basic statistical tests. Undergraduate students enrolled in the Instrumental Analysis Laboratory class at the University at Buffalo performed this experiment successfully during the 2015 spring semester.