Open AccessMethod development for the determination of elements in Hypericum perforatum L. (St John's wort) herb and preparations using inductively coupled plasma–optical emission spectroscopy and microwave digestion
Author(s) -
Owen Jade D.,
Evans Sara J.,
Guirguis Amira,
Kellett Kathryn,
Stair Jacqueline L.
Publication year - 2019
Publication title -
journal of pharmacy and pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 118
eISSN - 2042-7158
pISSN - 0022-3573
DOI - 10.1111/jphp.12742
Subject(s) - hypericum perforatum , herb , inductively coupled plasma atomic emission spectroscopy , microwave digestion , chemistry , calibration , inductively coupled plasma , hypericum , chromatography , analytical chemistry (journal) , traditional medicine , detection limit , plasma , medicinal herbs , mathematics , physics , medicine , statistics , quantum mechanics
Objectives A method was developed to analyze St John's wort ( Hypericum perforatum L.) herb and preparations using inductively coupled plasma–optical emission spectroscopy ( ICP ‐ OES ) to determine the quantity of 11 elements (Al, B, Ba, Ca, Cu, Fe, Mg, Mn, Ni, Sr and Zn). Methods This study includes the evaluation of digestion acids and calibration methods, as well as instrumental parameters such as choice of nebulizer and emission wavelength. Key findings Two nebulizers (Conikal and SeaSpray) performed similarly for most elements, and two optimum wavelengths were determined for each element. Five acids were evaluated for the digestion of the Polish Certified Reference Material Tea Leaves ( INCT ‐ TL ‐1), while three were taken forward to use for the different St John's wort formulations (i.e. herb, capsule and tablet). A simple protocol using 5 ml HNO 3 was sufficient in most cases; however, variability was observed for elements often bound in silicates (e.g. Al, Fe and Zn). An external weighted calibration was also found to be preferential over unweighted, and the use of standard addition affected some concentration values up to 20%. Conclusions Therefore, this paper presents the development and optimized method parameters to be used with ICP ‐ OES that will allow the analysis of 11 key elements present in St John's wort herb and preparations.