Abstract Background Hemp (Cannabis sativa L.) readily accumulates potentially toxic elements (PTEs) from soil. PTE exposure is linked to cancer, nephrotoxicity, and neurotoxicity. Non-intoxicating hemp products in New Jersey are not subject to mandatory PTE testing, posing a consumer safety risk. Objective This study presents a single-laboratory validation of an ICP OES method for the determination of As, Cd, Pb, and Hg in hemp, evaluated against AOAC SMPR 2020.001 performance criteria. Methods Ground hemp (0.125 g) was digested using HNO3/HCl/H2O2 (190 °C, 20 min) and diluted to 50 mL. Samples were analyzed on an Agilent 5800 ICP OES with a seven-point calibration (1–100 μg/L), Au/Sc internal standards, and KHP carbon for matrix matching. Results Spike recoveries for Cd (92.7%) and Pb (96.2%) met AOAC SMPR 2020.001 criteria (80–115%). Mercury recovery (47%) fell below acceptance limits due to matrix suppression and volatility losses. The As LOD (0.807 μg/g) exceeded sample concentrations in most specimens. LOQ values for all four elements exceeded the SMPR 2020.001 threshold of 10 µg/kg (0.01 µg/g). Calibration linearity was confirmed for all analytes (r ≥ 0.995). Conclusion Partial validation was achieved: Cd and Pb demonstrated acceptable accuracy and repeatability, but LOQ criteria were not met for any analyte. ICP OES is not suitable for Hg or As at regulatory trace levels; ICP MS is recommended for these elements. This method offers a cost-effective screening tool for Cd and Pb in hemp. Highlights This study presents the first single-laboratory ICP OES validation for PTEs in hemp under AOAC SMPR 2020.001. Cd and Pb met accuracy and repeatability criteria; As and Hg did not meet sensitivity requirements. ICP MS is recommended for regulatory As and Hg testing in hemp.
Sachdev et al. (Fri,) studied this question.