https://cyberleninka.org/article/n/398815.pdf

Analytical techniques in pharmaceutical analysis: A review

A real-time colorimetric and ratiometric fluorescent probe based on modulating the intramolecular charge transfer (ICT) of the coumarin platform for selective detection of sulfite is presented. This reaction based probe utilized the Michael addition to the dicyano-vinyl group with the detection limit of 5.8 × 10−5 M. The probe displayed a high selectivity for sulfite over other anions and reactive sulfur especially for biothiols including cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), with about 100 nm blue shift and more than 230 times intensity ratios change of the emission spectrum. Meanwhile, it could be easily observed that the probe for sulfite changes from red to pale yellow by the naked eye, and from red to blue under UV lamp immediately after the sulfite is added. To the best of our knowledge, it is the fastest response probe for sulfite ever reported, which could give a colorimetric and ratiometric fluorescent response instantly.

A real-time colorimetric and ratiometric fluorescent probe for sulfite.

Construction of a chemically modified electrode for the selective determination of nitrite and nitrate ions based on a new nanocomposite

Backround: The present review focuses on electrochemical methods for antioxidant capacity and its main contributors assessment. The main reactive oxygen species, responsible for low density lipo- protein oxidation, and their reactivity are reminded. The role of antioxidants in counteracting the factors leading to oxidative stress-related degenerative diseases occurence, is then discussed. Antioxidants can scavenge free radicals, can chelate pro-oxidative metal ions, or quench singlet oxygen. When endogenous factors (uric acid, bilirubin, albumin, metallothioneins, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase) cannot accomplish their protective role against reactive oxygen species, the intervention of exogenous antioxidants (vitamin C, tocopherols, flavonoids, carotenoids etc) is required, as intake from food, as nutritional supplements or as pharmaceutical products. Literature study: The main advantages of electrochemical methods with respect to traditional, more laborious instrumental techniques are described: sensitivity, rapidity, simplicity of the applied analytical procedure which does not require complicated sample pre-treatment etc. The paper reviews minutiously the voltammetric, amperometric, biamperometric, potentiometric and coulometric methods for total antioxidant capacity estimation. For each method presented, the electroactivity and the mechanism of electro-oxidation of antioxidant molecules at various electrodes, as well as the influences on the electroactive properties are discussed. The characteristics of the developed methods are viewed from the perspective of the antioxidant molecule structure influence, as well as from the importance of electrode material and/or surface groups standpoint. The antioxidant molecule-electrode surface interaction, the detection system chosen, the use of modifiers, as well as the nature of the analysed matrix are the factors discussed, which influence the performances of the studied electrochemical techniques. Conclusions: The electrochemical methods reviewed in this paper allow the successful determination of the total antioxidant capacity and of its main contributors in various media: foodstuffs and beverages, biological fluids, pharmaceuticals. The advantages and disadvantages of the electrochemical methods applied to antioxidant content and antioxidant activity assay are treated and interpreted, in the case of various analysed matrixes. Combining advanced materials with classical electrode construction, provides viable results and can constitute an alternative for the future.

https://www.degruyter.com/downloadpdf/j/chem.2015.13.issue-1/chem-2015-0099/chem-2015-0099.xml

Electrochemical Methods for Total AntioxidantCapacity and its Main Contributors Determination:A review

Sulfur dioxide (SO2) is a dangerous environmental pollutant. Excessive intake of it may cause some respiratory diseases and even lung cancer. The development of effective methods for detection of SO2 is of great importance for the environment and physiology. Herein, we have designed and synthesized a novel two-photon (TP) and deep-red emission ratiometric fluorescent probe (CP) for detection of SO2. Notably, the novel probe CP exhibited ultrafast response to SO2 in less than 5 s and displayed a great emission shift (195 nm) and a large emission signal ratio variation (enhancement from 0.1347 to 100.14). In addition, the unique probe was successfully employed for imaging SO2 not only in the mitochondria of living cells but also in brain tissues and zebrafishes.

Two-Photon and Deep-Red Emission Ratiometric Fluorescent Probe with a Large Emission Shift and Signal Ratios for Sulfur Dioxide: Ultrafast Response and Applications in Living Cells, Brain Tissues, and Zebrafishes

Determination of trace sulfite by direct and indirect methods using differential pulse polarography.

Determination of the food dye carmine in milk and candy products by differential pulse polarography

The objective of this study was to describe a new and simple method for the determination of histamine so that it can be used in routine food analysis. A square wave stripping voltammetric (SWSV) method has been used for the indirect determination of histamine. The method is based on accumulation copper (II) - histamine complex onto a hanging mercury drop electrode and reduction of complex. The optimum conditions include an accumulation potential of −420 mV (versus Ag/AgCl), an accumulation time of 10 s. Two linear calibration graphs were obtained with slopes of 0.078 (μM/μA) and 0.014 (μM/μA), respectively. The detection limits were found to be 3 × 10−7 and 1 × 10−5 M for histamine (S/N = 3), respectively. The validated SWSV method showed good linearity as well as satisfactory repeatability and immediate precision values, for both instrument and method. The effect of common excipients and metal ions on the peak height of Cu-histamine complex peak was studied. The method was successfully, applied to the determination of histamine in canned anchovy (Engraulis encrasicholus), frozen Tinca tinca (L.) and Cyprinus carpio fish samples.

/pdf/quantification-of-histamine-in-various-fish-samples-using-4zbgkgupx9.pdf

Ummihan Taskoparan Yilmaz

Papers

Determination of trace sulfite by direct and indirect methods using differential pulse polarography.

Determination of the food dye carmine in milk and candy products by differential pulse polarography

Quantification of histamine in various fish samples using square wave stripping voltammetric method

Determination of trace nitrite by direct and indirect methods using differential pulse polarography and application

Selective and sensitive determination of tannic acid using a 1-benzoyl-3-(pyrrolidine) thiourea film modified glassy carbon electrode