The applicability of the method to real samples was demonstrated
by analyzing NIST SRM 1547 Peach Leaves and NIST SRM
1573a Tomato Leaves reference materials and three different herb
powders (Astragalus membranaceus, Glycyrrhiza glabra and Angelica
sinensis) obtained locally. To ensure accuracy, the samples were
analyzed by standard addition and isotope dilution methods. The
slurry was prepared using the following procedure. A 0.05 g portion
of herbal powder was transferred into a 10 mL flask, 0.2 mL
HCl and 1.5 mL H2O were added