title: The determination of trace lead in Chinese medicinal herbs by flow injection analysis in polyethyleneglycol medium.
abstract: In this work, a new flow injection analysis (FIA) for the determination of Pb(2+) in Chinese medicinal herbs was developed. In the buffer solution of borax-NaOH (pH 10.5), Pb(2+) reacted with 2-[(5-bromo-2-pyridyl)-azo]-5-(diethyl-amino)phenol (5-Br-PADAP) to form a complex. The experimental results showed that the sensitivity was enhanced in the presence of polyethyleneglycol-800 (PG-800). The main factors affecting the determination were investigated in detail. Under the optimum conditions, the linear range and detection limit is 0.0-0.3microg/mL and 1.5ng/mL (correlation coefficient r=0.9996), respectively. The linear regression equation is A=-0.005+0.60c (microg/mL). The sample throughout is 10h(-1). Foreign substrates effects were also investigated. The proposed method has been successfully applied to the determination of lead in reference material, goldthread and lepidium seed.
authors: College of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou 225009, China.
authors: Aiqin
authors: A
authors: Gong
authors: Xiashi
authors: X
authors: Zhu
authors: Xiaoyan
authors: X
authors: Huang
authors: Yaqin
authors: Y
authors: Zhang
mesh_terms: D001391:Azo Compounds / Q000737:chemistry; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D017022:Flow Injection Analysis / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000032:analysis*; D011092:Polyethylene Glycols / Q000737:chemistry*; D012015:Reference Standards; D013057:Spectrum Analysis; D013997:Time Factors; D014131:Trace Elements / Q000032:analysis*; D014867:Water
chemical_list: D001391:Azo Compounds; D004365:Drugs, Chinese Herbal; D014131:Trace Elements; D014867:Water; C037882:2-(5-bromo-2-pyridylazo)-5-diethylaminophenol; D007854:Lead; D011092:Polyethylene Glycols