Determination of multi element levels in leaves and herbal teas from Turkey by ICP-OES

Abstract

ABSTRACT. We have determined the amount of some heavy metals (Al, Ba, Cr, Cu, Fe, Mn, Ni, Sr and Zn) contained in 18 herbal tea samples that had been bought from local markets where different parts of plants (leaves or flowers) are consumed especially for medical purposes in Turkey by ICP-OES. The validity of the analytical procedure was checked by analyzing INCT-TL-1 CRM certified reference material. The results from the analysis of CRM were all within the 95% reliability limit. The experiment results comply with the values reported in the literature. The wet decomposition method was used to solubilize the metals. The amount of the heavy metal that had passed to the tea via infusion has also been determined. The lowest and highest amounts of the metals found are: Al 268

Comparison and Validation of Different Alternative Sample Preparation Procedures of Tea Infusions Prior to Their Multi-Element Analysis by FAAS and ICP OES

“…The validated sample preparation procedure prior to the multi-element analysis of infusions of BTs and GTs with the use of FAAS and ICP OES proposed in the present work is certainly a very attractive alternative to procedures based on high-temperature evaporations of infusions and wet ashings of residues in concentrated reagents (Gallaher et al 2006;Salahinejad and Aflaki 2010;Tahir Soomro et al 2008) or invalidated measurements of untreated infusions of BTs and GTs (Altintig et al 2014;Dambiec et al 2013;Derun 2014;Froes et al 2014;Malik et al 2008;Mehra and Baker 2007;Memic et al 2014;Ozcan et al 2008;Schwalfenberg et al 2013;Street et al 2006) or acidified (Salahinejad and Aflaki 2010). Considering a possibility of the analysis of a great number of infusions of BTs and GTs in a simple way, the described green analytical sample treatment prior to measurements of concentrations of different metals by FAAS and ICP OES seems to be particularly important for multi-element screening studies and the quality control monitoring of teas as served.…”

“…The use of other procedures, particularly the direct analysis of infusions with their no previous treatment, was found useless. Surprisingly, there are many contributions in the literature, in which the direct analysis of infusions of BTs and GTs was used (Altintig et al 2014;Dambiec et al 2013;Derun 2014;Diniz et al 2015;Froes et al 2014;Jeszka-Skowron et al 2015;Malik et al 2008;Mehra and Baker 2007;Memic et al 2014;Ozcan et al 2008;Ozdemir et al 2014;Street et al 2006). Unfortunately, in the overwhelming majority of cited papers (with exception for Diniz et al 2015;Froes et al 2014), no validation of sample preparation procedures used and results achieved was undertaken.…”

“…The UV photolysis-assisted digestion in H 2 O 2 , aimed at destructing the organic matrix of infusions of tea, was also carried out (Dash et al 2008). Unfortunately, reported methods of the direct analysis of infusions of BTs and GTs (Altintig et al 2014;Dambiec et al 2013;Derun 2014;Jeszka-Skowron et al 2015;Malik et al 2008;Mehra and Baker 2007;Memic et al 2014;Ozcan et al 2008;Ozdemir et al 2014;Street et al 2006), or their acidification (Salahinejad and Aflaki 2010;Schwalfenberg et al 2013) were not validated nor verified, therefore, the quality of the data achieved in above-cited works could be questioned. Although spike-and-recovery experiments were made in case of few direct analyses of infusions and quantitative recoveries were obtained, i.e., 91.9-113 % for infusions of GTs (Froes et al 2014) and 85.2-113 % for infusions of BTs and GTs (Diniz et al 2015), it should be noted that the recovery study is selectively used and does not have a high priority when another analytical method is available for comparison purposes.…”

“…In addition, graphite furnace atomic absorption spectrometry (GFAAS) (JeszkaSkowron et al 2015;Wrobel et al 2000) and inductively coupled plasma mass spectrometry (ICP MS) (Milani et al 2015;Schwalfenberg et al 2013;Shen and Chen 2008;Sofuoglu and Kavcar 2008) were used. Among different sample preparation procedures reported so far for infusions of black (BTs) and green (GTs) teas before their spectrochemical analysis, it appears that no treatment and direct measurements of metals in them was preferred in case of FAAS (Dambiec et al 2013;Malik et al 2008;Memic et al 2014;Polechonska et al 2015), ICP OES (Altintig et al 2014;Derun 2014;Diniz et al 2015;Froes et al 2014;Malik et al 2008;Mehra and Baker 2007;Ozcan et al 2008;Ozdemir et al 2014;Street et al 2006, andGFAAS (Jeszka-Skowron et al 2015). In addition, infusions of teas were acidified with HNO 3 to a concentration of 0.28 mol L −1 (Salahinejad and Aflaki 2010) or 1.4 mol L −1 (Schwalfenberg et al 2013) or HCl to a concentration of 0.12 mol L −1 (Paz-Rodriguez et al 2015).…”

“…The most popular and extensively used in the analysis of tea infusions are spectrochemical methods, including flame atomic absorption spectrometry (FAAS) (Dambiec et al 2013;Gallaher et al 2006;Malik et al 2008;Memic et al 2014;Paz-Rodriguez et al 2015;Polechonska et al 2015;Tahir Soomro et al 2008) and inductively coupled plasma optical emission spectrometry (ICP OES) (Altintig et al 2014;Dash et al 2008;Diniz et al 2015;Derun 2014;Fernandez et al 2002;Froes et al 2014;Malik et al 2008;Mehra and Baker 2007;Ozcan et al 2008;Ozdemir et al 2014;Salahinejad and Aflaki 2010;Street et al 2006). In case of FAAS, it is particularly convenient in reference to selected metals that are highly abounded in tea infusions, i.e., Ca, Fe, K, Mg, Mn, and Na (Szymczycha-Madeja et al 2012).…”