1,721,063 research outputs found
Electrochemical study of Au(III) compounds with substituted pyridine and 2,2’-bipyridine ligands
No full textConducting Polymers in Amperometric Sensors: A State of the Art over the Last 15 Years with a Focus on Polypyrrole-, Polythiophene-, and Poly(3,4-ethylenedioxythiophene)-Based Materials
No full textConducting polymers are used in a wide range of applications, especially in the design and development of electrochemical sensors. Their main advantage, in this context, is their ability to efficiently modify an electrode surface using the direct polymerization of a suitable monomer in an electrochemical cell, or by physical coating. Additionally, the conducting polymers can be mixed with further materials (metal nanoparticles, carbonaceous materials) to enhance conductivity and analytical features (linear range, limit of detection, sensitivity, and selectivity). Due to their characteristics, conducting polymer-based amperometric sensors are applied to the determination of different organic and inorganic analytes. A view of recent advances in this field focusing on pyrrole, thiophene, and 3,4-ethylenedioxythiophene as starting materials is reported
Preliminary RP-HPLC approaches to the characterization of nutraceutical components in Stevia rebaudiana Bertoni leaves
No full textA Friendly Complexing Agent for Spectrophotometric Determination of Total Iron
Full text linkIron, one of the most common metals in the environment, plays a fundamental role in many biological as well as biogeochemical processes, which determine its availability in different oxidation states. Its relevance in environmental and industrial chemistry, human physiology, and many other fields has made it necessary to develop and optimize analysis techniques for accurate determination. Spectrophotometric methods are the most frequently applied in the analytical determination of iron in real samples. Taking advantage of the fact that desferrioxamine B, a trihydroxamic acid used since the 1970s in chelation therapy for iron overload treatment, forms a single stable 1:1 complex with iron in whichever oxidation state it can be found, a smart spectrophotometric method for the analytical determination of iron concentration was developed. In particular, the full compliance with the Lambert-Beer law, the range of iron concentration, the influence of pH, and the interference of other metal ions have been taken into account. The proposed method was validated in terms of LoD, LoQ, linearity, precision, and trueness, and has been applied for total iron determination in natural water certified material and in biological reference materials such as control human urine and control serum
A study on the evolution of 5-hydroxymethyl-2-furaldehyde in royal jelly stored at different conditions
No full textRoyal jelly (RJ) constitutes one of the most renowned products from beekeeping. It is secreted from the cephalic glandular system of young worker bees to feed the queen throughout her whole life and it is considered as the main responsible for the caste differentiation inside the beehive[1,2].
Many functional properties have been attributed to RJ and several biologically and pharmacologically active substances have been identified in its chemical composition[3,4]. Therefore, its commercial appeal has considerably grown in the last years and it can be nowadays considered as one of the most valuable nutraceutical products.
One of the main aspects related to RJ quality is represented by freshness. Improper storage conditions may cause modifications on the chemical composition of RJ affecting its health-promoting properties and its economic value. For this reason, it is generally recommended to keep RJ refrigerated during storage[5].
Several studies have been dedicated to the identification of a freshness marker for RJ but many of the proposed parameters are influenced by a large number of factors and don’t fit for purpose[5].
In the past our research group developed and validated a rapid RP-HPLC method for the determination of 5-hydroxymethyl-2-furaldehyde (HMF) in RJ [6]. In this study, the evolution of HMF in RJ stored at different conditions (RT, 4 °C and -18 °C) was investigated. Our results suggest that HMF could be very useful to discriminate between spoiled and fresh samples. Moreover a very good correlation (R2=0.9791) between HMF content and RT storage time was observed.
1. R Krell, Value-added products from beekeeping, 1996, FAO Agricultural Service Bulletin no.124, Food and Agriculture Organization of the United Nations Rome, http://www.fao.org/docrep/w0076E/w0076E00.htm, accessed 26 June 2014
2. M Kamakura, Nature, 473, 478, 2011
3. M Viuda-Martos, Y Ruiz-Navajas, J Fernàndez-Lopéz, J Pérez-Alvaréz, Journal of Food Science, 73, R117-R124, 2008
4.MF Ramadan, A Al-Ghamdi, Journal of Functional Foods, 4, 39-52, 2012
5.E Marconi, MF Caboni, MC Messia, G Panfili, Journal of Agricultural and Food chemistry, 50, 2825-2829, 2002
6. M Ciulu, R Farre, I Floris, VM Nurchi, A Panzanelli, MI Pilo, N Spano, G Sanna, Analytical Methods, 5, 5010-5013, 201
New chromatographic methods for the determination of 5-hydroxymethylfurfural in saccharidic-type foodstuffs. The strawberry tree honey
No full textMetodologie elettroanalitiche per la determinazione amperometrica del 5-idrossimetilfurfurale nel miele
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