| Autor(es): |
Virgilio, Alex
;
Amais, Renata Stabile
;
Schiavo, Daniela
;
Gomes Neto, Jose Anchieta
;
Nobrega, Joaquim de Araujo
Número total de Autores: 5
|
A procedure for the determination of As, Cd, Cr, Ni, Pb, and V in phytotherapy medicines by inductively coupled plasma-tandem mass spectrometry is reported. The use of tandem mass spectrometry with oxygen into an octopole reaction system at various gas flow rates and the combination of on-mass and mass-shift modes was evaluated. Cadmium, Cr, Ni, and Pb were determined as free atomic ions while As and V were determined as the oxides AsO+ and VO+ in the same run. Samples were prepared by microwave-assisted digestion with dilute nitric acid and hydrogen peroxide. Two plant-certified reference materials (apple leaves and tomato leaves) were used to check the accuracy. For tandem mass spectrometry with 0.5 mL min(-1) O-2, recoveries in the 85-113% were typically obtained and no statistical differences were observed at the 95% confidence level (t-test) in comparison with the certified values. Using these conditions, the limits of detection for the method were 0.01, 0.0002, 0.008, 0.008, 0.003, and 0.002 mu g g(-1) for As, Cd, Cr, Ni, Pb, and V, respectively. The procedure was used for the analysis of four phytotherapic drugs and the determined concentrations were up to 0.168 mu g g(-1) As, 0.03 mu g g(-1) Cd, 0.82 mu g g(-1) Cr, 1.18 mu g g(-1) Ni, 0.52 mu g g(-1) Pb, and 2.4 mu g g(-1) V with average precision values of 8% as the relative standard deviation. The found concentrations were compared with limits proposed in official guidelines and, in most cases, the values were below the maximum limits allowed. (AU) |