scholarly journals Mercury Analysis of Acid- and Alkaline-Reduced Biological Samples: Identification of meta-Cinnabar as the Major Biotransformed Compound in Algae

2006 ◽  
Vol 72 (1) ◽  
pp. 361-367 ◽  
Author(s):  
David Kelly ◽  
Kenneth Budd ◽  
Daniel D. Lefebvre
Keyword(s):  
Biological Samples ◽  
Mercury Species ◽  
Selective Method ◽  
Aerobic Conditions ◽  
Mercury Compounds ◽  
Mercury Analysis ◽  
Nonprotein Thiol ◽  
Acid Reduction

ABSTRACT The biotransformation of HgII in pH-controlled and aerated algal cultures was investigated. Previous researchers have observed losses in Hg detection in vitro with the addition of cysteine under acid reduction conditions in the presence of SnCl2. They proposed that this was the effect of Hg-thiol complexing. The present study found that cysteine-Hg, protein and nonprotein thiol chelates, and nucleoside chelates of Hg were all fully detectable under acid reduction conditions without previous digestion. Furthermore, organic (R-Hg) mercury compounds could not be detected under either the acid or alkaline reduction conditions, and only β-HgS was detected under alkaline and not under acid SnCl2 reduction conditions. The blue-green alga Limnothrix planctonica biotransformed the bulk of HgII applied as HgCl2 into a form with the analytical properties of β-HgS. Similar results were obtained for the eukaryotic alga Selenastrum minutum. No evidence for the synthesis of organomercurials such as CH3Hg+ was obtained from analysis of either airstream or biomass samples under the aerobic conditions of the study. An analytical procedure that involved both acid and alkaline reduction was developed. It provides the first selective method for the determination of β-HgS in biological samples. Under aerobic conditions, HgII is biotransformed mainly into β-HgS (meta-cinnabar), and this occurs in both prokaryotic and eukaryotic algae. This has important implications with respect to identification of mercury species and cycling in aquatic habitats.

scholarly journals Fractional Determination of Mercury Species in Biological Samples by Use of HPLC and Cold Vapor Atomic Fluorescence Spectrometry

2012 ◽  
Vol 61 (12) ◽  
pp. 1073-1077 ◽  
Author(s):  
Kentaro HAYASHI ◽  
Joji OHSAKO ◽  
Tsunenori NAKAJIMA ◽  
Hirokazu TAKANASHI ◽  
Akira OHKI
Keyword(s):  
Biological Samples ◽  
Fluorescence Spectrometry ◽  
Atomic Fluorescence Spectrometry ◽  
Mercury Species ◽  
Atomic Fluorescence ◽  
Cold Vapor

scholarly journals Development and application of a validated HPLC method for the analysis of dissolution samples of mexiletine hydrochloride capsules

2010 ◽  
Vol 75 (7) ◽  
pp. 975-985 ◽  
Author(s):  
Dragan Milenovic ◽  
Zoran Todorovic
Keyword(s):  
Flow Rate ◽  
Mobile Phase ◽  
Hplc Method ◽  
Uv Detection ◽  
In Vitro Dissolution ◽  
Selective Method ◽  
Dissolution Studies ◽  
Detection And Quantification

The aim of this work was to develop and validate a simple, efficient, sensitive and selective method for the analysis of dissolution samples of mexiletine hydrochloride capsules by HPLC without the necessity of any time-consuming extraction, dilution or evaporation steps prior to drug assay. Separation was performed isocratically on a 5 ?m LiChrospher 60, RP-Select B column (250 x 4 mm ID) using the mobile phase buffer-acetonitrile (60:42, v/v) at a flow rate of 1.2 mL min-1 and UV detection at 262 nm. The elution occurred in less than 10 minutes. The assay was linear in the concentration range 50-300 ?g mL-1 (r2 = 0.9998). The validation characteristics included accuracy, precision, linearity, specificity, limits of detection and quantification, stability, and robustness. Validation acceptance criteria were met in all cases (the percent recoveries ranged between 100.01 and 101.68 %, RSD < 0.44 %). The method could be used for the determination of mexiletine hydrochloride and for monitoring its concentration in in vitro dissolution studies.

Development of a mild mercaptoethanol extraction method for determination of mercury species in biological samples by HPLC–ICP-MS

Talanta ◽  
2007 ◽  
Vol 71 (5) ◽  
pp. 2034-2039 ◽  
Author(s):  
M WANG ◽  
W FENG ◽  
J SHI ◽  
F ZHANG ◽  
B WANG ◽  
...  
Keyword(s):  
Biological Samples ◽  
Extraction Method ◽  
Mercury Species ◽  
Icp Ms

scholarly journals Combining derivative and synchronous approaches for simultaneous spectrofluorimetric determination of terbinafine and itraconazole

2020 ◽  
Vol 7 (8) ◽  
pp. 200571
Author(s):  
Heba Elmansi ◽  
Aya Roshdy ◽  
Shereen Shalan ◽  
Amina El-Brashy
Keyword(s):  
Biological Samples ◽  
Concentration Level ◽  
Detection Limits ◽  
Plasma Samples ◽  
International Conference ◽  
Spiked Plasma ◽  
Spectrofluorimetric Determination ◽  
Good Agreement

In this study, determination of terbinafine and itraconazole down to biological concentration level has been carried out. The determination is based on increasing the selectivity of the spectrofluorimetric technique by combining both derivative and synchronous spectrofluorometric approaches, which permits successful estimation of terbinafine at 257 nm and itraconazole at 319 nm in the presence of each other at Δ λ of 60 nm. International Conference on Harmonization validation guidelines were followed to fully validate the method, and linearity was obtained for the two drugs over the range of 0.1–0.7 µg ml −1 for terbinafine and 0.5–4.0 µg ml −1 for itraconazole. Application of the method was successfully carried out in the commercial tablets with good agreement with the comparison spectrofluorometric methods. As the detection limits were down to 0.013 and 0.1 µg ml −1 and quantitation limits were 0.04 and 0.032 µg ml −1 for terbinafine and itraconazole, respectively; the in vitro determination of terbinafine and itraconazole in spiked plasma samples was applicable. The percentage recoveries in biological samples were 97.17 ± 4.54 and 98.75 ± 2.25 for terbinafine and itraconazole, respectively. Water was used as the optimum diluting solvent in the proposed methodology which adds an eco-friendly merit.

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