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The evolution in foodstuff-monitoring processes has increased the number of studies on biogenic amines (BAs), in recent years. This trend with future perspective needs to be assembled to address the associated health risks. Thus, this study aims to cover three main aspects of BAs: (i) occurrence, physiology, and toxicological effects, most probable formation mechanisms and factors controlling their growth; (ii) recent advances, strategies for determination, preconcentration steps, model technique, and nature of the matrix; and (iii) milestone, limitations with existing methodologies, future trends, and detailed expected developments for clinical use and on-site ultra-trace determination. The core of the ongoing review will discuss recent trends in pre-concentration toward miniaturization, automation, and possible coupling with electrochemical techniques, surface-enhanced Raman scattering, spectrofluorimetry, and lateral flow protocols to be exploited for the development of rapid, facile, and sensitive on-site determination strategies for BAs. [ABSTRACT FROM AUTHOR]

The study reports a simple and highly selective spectrofluorometric method for trace determination and speciation of chromium(iii & vi) species in water using 10-(3-dimethylaminopropyl) phenothiazine hydrochloride, namely, promazine hydrochloride (PMH) as a fluorescence tagging reagent. The method is based on the redox reaction between PMH and chromium(vi) in aqueous H3PO4, resulting in the formation of complex [Cr(iii)–PMH] followed by fluorescence quenching at λex/em = 300/449 nm. An exceptional value for the limit of detection (LOD = 0.03 μg L−1) is attained with a linear range of 0.1–1.0 μg L−1 under the optimized conditions. A coefficient of variation (CV) of ±2.05% (n = 5) is obtained at 2.0 μg L−1 level of chromium(vi). Chemical speciation of the chromium(iii & vi) species is successfully accomplished after the oxidation of chromium(iii) to chromium(vi) with H2O2 in KOH solution at pH 9.0. The method is validated in environmental water samples with satisfactory recovery percentages (＞97.7%) using inductively coupled plasma-optical emission spectrometry (ICP-OES). The proposed and reference methods are subjected to statistical treatment (student's t and F tests) at 95% confidence with no significant difference, indicating the precision and accuracy of the proposed optical probe. [ABSTRACT FROM AUTHOR]

The current study explores the use of quercetin for developing a highly selective spectrofluorimetric methodology for trace determination, speciation and thermodynamic characterization of tungstate (WO 4 2 and quercetin with subsequent increase in the emission intensity. The developed method could be applied successfully in a wide linear range (1.0-400.0 μg L - ) with a detection limit of 0.28 μg L 4 2 -  = 400/492 nm. The developed method was successfully applied in real tap and waste water samples. The suitability of the proposed method was further validated by inductively coupled plasma-optical emission spectrometry (ICP-OES) in terms of student's t and F tests at 95% confidence. Characterization (NMR, FTIR and electronic spectra), stoichiometry, stability constant, fluorescence mechanism and thermodynamic parameters (ΔH, ΔS, and ΔG) of the produced complex species were evaluated and properly assigned. The fluorescence quenching mechanism of tungstate quercetin complex by Triton X-100 was also evaluated for computing Stern-Volmer quenching constant and approximating quenching sphere. The method showed a clear significance over most of the reported methods for tungsten in literature in terms of good accuracy, robustness, ruggedness, short analytical time and cost-effectiveness.-1 ) with a detection limit of 0.28 μg L - 1 and quantification limit of 0.92 μg L -1 at λ ex/em  = 400/492 nm. The developed method was successfully applied in real tap and waste water samples. The suitability of the proposed method was further validated by inductively coupled plasma-optical emission spectrometry (ICP-OES) in terms of student's t and F tests at 95% confidence. Characterization (NMR, FTIR and electronic spectra), stoichiometry, stability constant, fluorescence mechanism and thermodynamic parameters (ΔH, ΔS, and ΔG) of the produced complex species were evaluated and properly assigned. The fluorescence quenching mechanism of tungstate quercetin complex by Triton X-100 was also evaluated for computing Stern-Volmer quenching constant and approximating quenching sphere. The method showed a clear significance over most of the reported methods for tungsten in literature in terms of good accuracy, robustness, ruggedness, short analytical time and cost-effectiveness., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)