The determination of free sulfide and cyanide by pulsed amperometric detection (PAD) at a silver-working electrode was improved through a deep de-oxygenation (at least 10 min) of both standard and real solutions containing the two analytes and adopting a two-potential waveform able to eliminate Ag working electrode fouling. The waveform stepped around the oxidation of Ag in the presence of 0.1-0.4 M hydroxyl ion, from -0.1 to 0.1 V versus saturated calomel electrode (SCE). The eluent composition (0.4 M NaOH plus 7.5 mM oxalate solution) allowed a very good column efficiency and selectivity. The presence of a polysulfide species was hypothesized in sulfide solutions that had not been de-oxygenated and aged. The polysulfide eluted just before sulfide and was confirmed by a chemical test with SO3(2-) producing the elimination of the polysulfide peak. Detection limits, according to the Hubaux-Vos method, were 1.0 and 2.0 microg/l for S2- and CN , respectively. We demonstrated good performance of the optimized method by repeatedly injecting standard solutions and by analyzing different real matrices. The method exhibited very good accuracy and repeatability (10 microg/l and a 500 microl injection loop, had a repeatability better than 3% for sulfide and 100 microg/l had a repeatability better than 1% for cyanide). The two-potential waveform ensured long-term stability of the electrode surface that required no manual polishing procedure for at least 1 month (20 analysis per day).
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.chroma.2003.10.001 | DOI Listing |
Pharmaceuticals (Basel)
December 2024
Department of Physiology, University of Louisville School of Medicine, Louisville, KY 40202, USA.
Late-onset Alzheimer's disease (LOAD) is a chronic, multifactorial, and progressive neurodegenerative disease that associates with aging and is highly prevalent in our older population (≥65 years of age). This hypothesis generating this narrative review will examine the important role for the use of sodium thiosulfate (STS) as a possible multi-targeting treatment option for LOAD. Sulfur is widely available in our environment and is responsible for forming organosulfur compounds that are known to be associated with a wide range of biological activities in the brain.
View Article and Find Full Text PDFPhysiol Plant
November 2024
College of Horticulture, Gansu Agricultural University, Lanzhou, China.
Nitric oxide (NO) and hydrogen sulphide (HS) play important roles in plant growth, development and environmental adaptation. Currently, there is few information on the mechanism by which HS may be involved in NO-induced salt tolerance. In this study, cucumber was used to investigate the role of NO and HS and their relationship under salt stress.
View Article and Find Full Text PDFBiomaterials
April 2025
Department of Ultrasound and Chongqing Key Laboratory of Ultrasound Molecular Imaging, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, PR China. Electronic address:
Materials (Basel)
October 2024
Laboratory of Advanced Technologies in Non-Ferrous and Ferrous Metals Raw Materials Processing, Institute of New Materials and Technologies, Ural Federal University Named After the First President of Russia B.N. Yeltsin (UrFU), 620002 Yekaterinburg, Russia.
Autoclave leaching of sulfide concentrates may produce various ferric secondary phases, depending on the arsenic content and temperature. Silver is converted to argentojarosite, from which it is not recoverable by standard cyanidation methods. To increase silver recovery, it is necessary to reduce the argentojarosite formation during autoclave leaching.
View Article and Find Full Text PDFJ Environ Manage
December 2024
Central Mining Institute - National Research Institute GIG-PIB, Department of Energy Saving and Air Protection, Plac Gwarków 1, 40-166, Katowice, Poland.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!