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Graphite furnace atomic absorption spectrometric determination of cadmium after solid-liquid extraction with dithizone
A Nezhadali, S Nazari
Bulletin of the Chemical Society of Ethiopia , 2009,
Abstract: A method for the determination of trace amount of cadmium ion after preconcentration by extracting its dithizone complex into molten naphthalene was developed. Several experimental conditions such as pH of the solution, stirring time, the amounts of naphthalene, standing time and volume of the solution were optimized. Trace amount of cadmium ion in aqueous solution of sample was chelated with 5 mL of 0.001 M dithizone at pH 8. After addition of 0.15 g naphthalene, the solution was heated to about 85 oC and stirred (800 rpm) for 2 min to reproduce the microcrystalline naphthalene. Cadmium ion was determined by a graphite furnace atomic absorption spectrometer. The interfering effects of diverse concomitant ions (cations and anions) were investigated. Artificial sea water and a standard reference material (SRM) were analyzed by this method. The sensitivity and detection limit of 1.2 ngL-1 and 1.5 ng L-1 were found, respectively.
Graphite furnace atomic absorption spectrometric determination of cadmium after solid-liquid extraction with dithizone  [cached]
Azizollah Nezhadali,Saied Nazari
Bulletin of the Chemical Society of Ethiopia , 2009,
Abstract: A method for the determination of trace amount of cadmium ion after preconcentration by extracting its dithizone complex into molten naphthalene was developed. Several experimental conditions such as pH of the solution, stirring time, the amounts of naphthalene, standing time and volume of the solution were optimized. Trace amount of cadmium ion in aqueous solution of sample was chelated with 5 mL of 0.001 M dithizone at pH 8. After addition of 0.15 g naphthalene, the solution was heated to about 85 oC and stirred (800 rpm) for 2 min to reproduce the microcrystalline naphthalene. Cadmium ion was determined by a graphite furnace atomic absorption spectrometer. The interfering effects of diverse concomitant ions (cations and anions) were investigated. Artificial sea water and a standard reference material (SRM) were analyzed by this method. The sensitivity and detection limit of 1.2 ngL-1 and 1.5 ng L-1 were found, respectively.
Herbal Medicines for Immunosuppression
Zahra Amirghofran
Iranian Journal Of Allergy, Asthma and Immunology , 2012,
Abstract: Herbal medicines have been used for centuries to treat different illnesses.Among more than 20,000 herbal medicines available for humans,a limited number have sufficiently been studied and numerous remained to be investigated for their efficacy in treating human diseases.A number of herbal products are in use for their immunosuppressive effects.This capacity of herbs may have useful applications in immune-mediated disorders including autoimmune diseases and organ transplant rejection. Plants such as Salvia miltiorrhiza and Tripterygium wilfordii has been shown to reduce inflammatory cytokines and mediators, indicating their value in the treatment of acute graft rejections and autoimmunity. Tanacetum parthenium inhibits the release of pro-inflammatory mediators from macrophages and lymphocytes and Curcuma longa down regulates the expression of cytokines and chemokines as well as the transcription factor NF-kappaB.There has been growing interest to investigate novel anti-inflammatory or immunosuppressive activities from various sources particularly herbal medicines.This review focuses on the plants that have recently received more attention regarding their influence on the immune system, being reported as immunosuppressive and anti-inflammatory agents and promising protective effects for immune-mediated diseases.
Determination of Pb and Cd in Garlic Herb (Allium sativum) Planted in Gilan and Khuzestan Provinces Using Graphite Furnace Atomic Absorption Spectrometry  [cached]
Zahra Ramezani,Nasrin Aghel,Negar Amirabedin
Jundishapur Journal of Natural Pharmaceutical Products , 2012,
Abstract: Background: Foods are enriched with variety of chemical elements . Some of these elements are necessary for human health . These elements enter in liquid, the cells and other organs , certain amount of these elements are essential for body organs to work properly..Objectives: This research was conducted to compare the level of lead and cadmium contamination in garlic species planted in Ramhormoz and Rasht and discuss about the source of this contaminations..Materials and Methods: Twenty composite samples were collected from each province, Khozestan (Ramhormoz) and Gilan (Rasht). Each sample was burned according to instruction reported in AOAC. Then the white residue was dissolved in diluted nitric acid then the Pb and Cd contents were determined using graphite furnace atomic absorption spectrometer at 217 and 228.8 nm, respectively. No Pb level was detected in garlic cultured in both cities. The mean concentration of cadmium was 0.40 and 0.58 mg/kg in garlics planted in Ramhormoz and Rasht, respectively..Results: Statistical analysis showed significant difference between mean concentration of cadmium in Rasht garlic and the permitted value (P < 0.001). The cadmium level in Rasht garlic is much higher than the standard level..Conclusions: In order to test the reliability of the data obtained using this method, randomly selected samples were spiked with Pb and Cd standard solutions. The cadmium and lead recovery were reported 93.93 and 90.18 percent.
Regulation of herbal medicines in Brazil: advances and perspectives
Carvalho, Ana Cecília Bezerra;Perfeito, Jo?o Paulo Silvério;Costa e Silva, Leandro Viana;Ramalho, Lívia Santos;Marques, Robelma France de Oliveira;Silveira, Damaris;
Brazilian Journal of Pharmaceutical Sciences , 2011, DOI: 10.1590/S1984-82502011000300004
Abstract: the national policy of integrative and complementary practices (pnpic) in the brazilian unified health system (sus), and the national policy of medicinal plants and herbal medicines (pnpmf) were launched in 2006. based on these, the brazilian health surveillance agency (anvisa) re-edited rules related to herbal medicines such as the guideline to herbal medicine registration (rdc 14/10), the good manufacture practices guideline (rdc 17/10) and the list of references to assess the safety and efficacy of herbal medicines (in 05/10). the requisites to prove herbal medicine's safety and efficacy were updated. therefore, this review aims at presenting and commenting these new rules.
Formation mechanism of the graphite-rich protective layer in blast furnace hearths  [PDF]
Ke-xin Jiao,Jian-liang Zhang,Zheng-jian Liu,Feng Liu,Li-sheng Liang
- , 2016, DOI: https://doi.org/10.1007/s12613-016-1206-3
Abstract: A long campaign life of blast furnaces is heavily linked to the existence of a protective layer in their hearths. In this work, we conducted dissection studies and investigated damage in blast furnace hearths to estimate the formation mechanism of the protective layer. The results illustrate that a significant amount of graphite phase was trapped within the hearth protective layer. Furthermore, on the basis of the thermodynamic and kinetic calculations of the graphite precipitation process, a precipitation potential index related to the formation of the graphite-rich protective layer was proposed to characterize the formation ability of this layer. We determined that, under normal operating conditions, the precipitation of graphite phase from hot metal was thermodynamically possible. Among elements that exist in hot metal, C, Si, and P favor graphite precipitation, whereas Mn and Cr inhibit this process. Moreover, at the same hot-face temperature, an increase of carbon concentration in hot metal can shorten the precipitation time. Finally, the results suggest that measures such as reducing the hot-face temperature and increasing the degree of carbon saturation in hot metal are critically important to improve the precipitation potential index.
Minimizing Chloride Interferences Produced by Calcium Chloride in the Determination of Cd by Graphite Furnace Atomic Absorption Spectrometry  [PDF]
Christophe Waterlot,Francis Douay
ISRN Spectroscopy , 2012, DOI: 10.5402/2012/415631
Abstract: Cadmium concentrations in CaCl2 extracting solutions at various concentrations were determined by graphite furnace atomic absorption using two background correctors: the deuterium and the high-speed self-reversal background correction systems. Under- and overestimation of the Cd absorbance signals in CaCl2 solutions were observed for concentrations greater than 0.005?M using the deuterium lamp while no important effect was observed using the other background correction system. The analytical performance of the spectrometer for the determination of Cd was studied in 0.01?M CaCl2 solution and single extractions were performed using reference materials and contaminated soil samples. Cadmium was determined using the two background correction systems and a third method, which consists of the use of the deuterium lamp without any chemical modifier, was added to the study. The results showed that the third method was unable to determine Cd concentrations in the CaCl2 solution due to the presence of extractable arsenic and iron. For solutions without any dilution or diluted with a very low dilution factor, the CaCl2-extractable Cd concentrations measured using the deuterium lamp were systematically below those found using the high-speed self-reversal method. These differences were explained by the presence of chloride ions in the atomization step. 1. Introduction Cadmium uptake by organisms is poorly related to the total Cd concentrations in contaminated soils [1]. Many studies pointed out that the chemical behavior and the potential toxicity of metals (often related to their environmental availability to organisms) depended on the binding of metals with ligands [2–6]. Depending on the physicochemical parameters of the soils, the soluble metals usually react with organic (humic and fulvic acids) as well as inorganic (sulfate, sulfide, phosphate, carbonate, oxide and hydroxide, and chloride) ligands. The most-studied ligand is probably the chloride ion because salinity increases Cd-uptake by plants by forming environmentally available Cd-chloro complexes as and CdCl2 [5, 7–13]. The prediction of metal bioavailability is of crucial importance for the assessment of environmental quality of contaminated soils. Thus, to understand the processes involved in metal uptake by plants (phytoavailability), the use of extracting solutions rather than the total metal contents is so recommended [13–16]. Among salt solutions used in single extractions, calcium chloride (CaCl2) appears as the most widely used extractant to assess plant-available Cd concentrations in soils
Herbal medicines: old and new concepts, truths and misunderstandings  [cached]
Fabio Carmona,Ana Maria Soares Pereira
Revista Brasileira de Farmacognosia , 2013,
Abstract: Men have been using herbal medicines for thousands of years. The advantages of this type of therapeutics include good availability, local cultural aspects, individual preferences, the increasing demand for natural and organic products, and the already validated synergistic effects of herbal medicines. However, ethically, the scope and limits of these drugs need to be established not only by ethnopharmacological evidences but also by scientific investigations, which confirm the therapeutic effects. With this study, we propose to discuss the possible advantages of using herbal medicines instead of purified compounds, the truth and myths about herbal medicines, drug discovery, and the implications for medical education and health care.
Pharmacovigilance of herbal medicines: Current state and future directions  [cached]
Shetti Sandeep,Kumar C,Sriwastava Neeraj,Sharma Indra
Pharmacognosy Magazine , 2011,
Abstract: Currently, a majority of the adverse events related to the use of herbal products and herbal medicines that are reported are attributable either to poor product quality or to improper use. Inadequate regulatory measures, weak quality control systems, and largely uncontrolled distribution channels (including mail order and Internet sales) may have been contributing to the occurrence of such events. In order to expand the knowledge about genuine adverse reactions to herbal medicines, and to avoid wasting scarce resources for identifying and analyzing adverse events, events resulting from such situations will need to be reduced or eliminated. Member States of the World Health Organization (WHO) are therefore encouraged to strengthen national regulation, registration and quality assurance and control of herbal medicines. In addition, the national health authorities should give greater attention to consumer education and to qualified practice in the provision of herbal medicines.
Chemical markers for the quality control of herbal medicines: an overview
Songlin Li, Quanbin Han, Chunfeng Qiao, Jingzheng Song, Chuen Lung Cheng, Hongxi Xu
Chinese Medicine , 2008, DOI: 10.1186/1749-8546-3-7
Abstract: Herbal medicines, also known as botanical medicines or phytomedicines, refer to the medicinal products of plant roots, leaves, barks, seeds, berries or flowers that can be used to promote health and treat diseases. Medicinal use of plants has a long history worldwide. According to the World Health Organization (WHO), traditional herbal preparations account for 30–50% of the total medicinal consumption in China [1]. There have always been concerns about the inconsistent composition of herbal medicines and occasional cases of intoxication by adulterants and/or toxic components. Quality control of herbal medicines aims to ensure their consistency, safety and efficacy.Chemical fingerprinting has been demonstrated to be a powerful technique for the quality control of herbal medicines. A chemical fingerprint is a unique pattern that indicates the presence of multiple chemical markers within a sample.The European Medicines Agency (EMEA) defines chemical markers as chemically defined constituents or groups of constituents of a herbal medicinal product which are of interest for quality control purposes regardless whether they possess any therapeutic activity [2]. Ideally, chemical markers should be unique components that contribute to the therapeutic effects of a herbal medicine. As only a small number of chemical compounds were shown to have clear pharmacological actions, other chemical components are also used as markers. The quantity of a chemical marker can be an indicator of the quality of a herbal medicine.The overall quality of a herbal medicine may be affected by many factors, including seasonal changes, harvesting time, cultivation sites, post-harvesting processing, adulterants or substitutes of raw materials, and procedures in extraction and preparation. From harvesting to manufacturing, chemical markers play a crucial role in evaluating the quality of herbal medicines. Moreover, the study of chemical markers is applicable to many research areas, including authenti
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