A method with negligible blank values for the determination of total iron at the ultratrace level in seawater has been optimized and validated exploring for the first time the performance and limitations of Adsorptive Cathodic Stripping Voltammetry (AdCSV) in non-buffered solutions. The method is based on the CSV determination of the Fe-dihydroxynaphthalene (DHN) complex using atmospheric oxygen to catalytically enhance the signal via hydrogen peroxide formation at the electrode/solution interface. The accumulation of hydroxyl ions, the by-product of the hydrogen peroxide formation, increased the pH in the diffusion layer in the absence of buffer bringing it to 9, the optimum for the analytical performance of the method. Voltammograms in UV digested seawater showed no stability or reproducibility drawbacks. The negligible, lower than 5pM, blank level, is due to the simplicity of the procedure requiring no sample manipulation and a maximum of three reagents only, necessarily the ligand DHN and a base only for those samples previously acidified to raise the pH to circumneutral values (here HCl and NH3 according to common trace metals protocols). These reagents do not require cleaning before use, further simplifying the overall procedure. Analysis of seawater previously acidified at pH ~1.5 with HCl and neutralized with ammonia showed interferences due to the buffering properties of the NH3/NH4Cl couple and the transient formation of a volatile electroactive interference that can be easily removed by simply allowing a set time before analysis. In general, the proposed method features several advantages, including high sample throughput, an excellent limit of detection at 12pM, minimum sample handling (no preconcentration or change of matrix is required), cost effectiveness and mainly a negligible blank. The method was successfully validated using open ocean consensus samples (SAFe D2 and S).
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http://dx.doi.org/10.1016/j.talanta.2015.12.060 | DOI Listing |
Exp Eye Res
January 2025
Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA. Electronic address:
Purpose: Keratin contamination is a common problem in mass spectrometry proteomic analyses, particularly in bottom-up mass spectrometry. The purpose of this study was to determine the protein contaminants introduced during the proteomic analysis of tear fluid.
Methods: Human tear fluid samples were collected using Schirmer strips.
Talanta
January 2025
Institute of Antibody Engineering, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, 510515, Guangdong, PR China. Electronic address:
J Hazard Mater
December 2024
Department of Environmental Science, University of California, Riverside, CA 92521, USA.
Nanoscale
November 2024
Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India.
Targeted cancer therapy using nanocarriers has emerged as a promising solution to the majority of drawbacks associated with conventional chemotherapy. The present research work describes the development of folic acid (FA)-targeted redox responsive [S-(PLA--PEG-CONH)] polymeric nanoparticles for the co-delivery of pirarubicin (Pira) and salinomycin (Sal). The nanoparticles' redox responsiveness arises from embedded disulfide bonds within the polymer, which gradually break in response to high GSH levels in tumors, enabling sustained drug release.
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July 2024
Ghent University, Department of Chemistry, Atomic & Mass Spectrometry - A&MS Research Unit Campus Sterre, Krijgslaan 281 - S12 9000 Ghent Belgium
In this work, an analytical approach was developed for Pb, Sr, and Fe isotopic analysis of archaeological samples recovered from an iron work site by using multi-collector inductively coupled plasma - mass spectrometry (MC-ICP-MS). The sample types include slag, coal, clay and hammer scales, all obtained from an archaeological site at Hoeke (Belgium). Despite the wide concentration range of the target elements present in the samples and some sample manipulations necessarily performed outside of a clean laboratory facility, the analytical procedure yielded accurate and precise results for QA/QC standards while blank levels were negligible.
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