An on-line chromium preconcentration and determination system implemented with flame atomic absorption spectrometry (FAAS) associated to flow injection (FI) was studied. For the retention of chromium, 4-(2-Thiazolylazo)-resorcinol (TAR) and Amberlite XAD-16 were used, at pH 5.0. The Cr-TAR complex was removed from the micro-column with ethanol. An enrichment factor of 50 was obtained for the preconcentration of 50 ml of sample solution. The detection limit value for the preconcentration of 50 ml of aqueous solution of Cr was 20 ng l(-1). The precision for ten replicate determinations at the 5 microg l(-1) Cr levels was 2.9% relative standard deviation (RSD), calculated from the peak heights obtained. The calibration graph using the preconcentration system for chromium was linear with a correlation coefficient of 0.9997 at levels near the detection limits up to at least 100 microg l(-1). The method was successfully applied to the determination of chromium in parenteral solution samples.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/s0731-7085(02)00604-0 | DOI Listing |
Food Chem
December 2024
Department of Food Safety and Quality Control, Research Institute of Food Science and Technology (RIFST), Mashhad, Iran.
This study demonstrates a new extraction method for determination of aflatoxins (AFs) in food samples by a GO-SiO/ZnO/FeO nanocomposite as new and effective sorbent. The nanocomposite structure was confirmed by FT-IR, XRD, EDX, FE-SEM, TEM, and mapping techniques. Optimization of the extraction process was conducted by investigating pH, adsorbent amount, sample volume, and solvent volume using central composite design (CCD).
View Article and Find Full Text PDFAnal Chem
January 2025
Nano Lithography and Manufacturing Research Center, Korea Institute of Machinery and Materials, 156 Gajeongbuk-ro, Daejeon 34103, South Korea.
Efficient separation and preconcentration of nanoparticles are crucial in a wide range of biomedical applications, particularly as target substances continue to diminish in size. In this study, we introduce an electric field-assisted membrane system that synergistically combines oversized-pore membranes with an electrokinetic particle retention mechanism. Utilizing Ti/Au-coated poly(tetrafluoroethylene) (PTFE) membranes, our approach generates electrokinetic forces to effectively separate and retain charged nanoparticles even smaller than the pores, achieving a separation efficiency over 99% and a preconcentration factor of 1.
View Article and Find Full Text PDFTalanta
December 2024
Department of Chemistry, Faculty of Basic Sciences, Ayatollah Boroujerdi University, Boroujerd, Iran.
Monitoring paracetamol levels in environmental samples is essential, as this widely used pharmaceutical can degrade water quality and adversely affect both ecosystems and human health. To address this issue, a novel, simple, sensitive, and accurate method has been developed. This method employs a functionalized ionic liquid, 2-(4-hydroxybenzyl)hydrazinium chloride ([HBH][Cl]), specifically designed to structurally mimic paracetamol and function as a complexing agent.
View Article and Find Full Text PDFACS Omega
December 2024
School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
As natural resources continue to be exploited, dense medium cyclones (DMCs) are increasingly utilized for the preconcentration of low-grade ores to meet the demands for higher feed grade, increased processing capacity, and reduced energy consumption. However, determining the optimal fineness of ferrosilicon remains ambiguous for different types of ores and is often described as more of an art than a science. This paper investigates the subtle effects of ferrosilicon fineness on flow field characteristics, medium classification, and the ore separation process using a validated numerical approach, which integrates a two-fluid model, a turbulence dispersion model, and a discrete phase model.
View Article and Find Full Text PDFEnviron Monit Assess
December 2024
Chemistry Department, Faculty of Art and Science, Yıldız Technical University, 34220, Istanbul, Türkiye.
In this study, a preconcentration strategy based on Ni(OH) nanoflowers (NFs) was developed for the extraction/separation of bismuth ions from environmental water samples before the determination by flame atomic absorption spectrometry (FAAS). The homogeneous coprecipitation method was employed for the synthesis of the flower-shaped Ni(OH) and used as an adsorbent for the preconcentration of bismuth. The extraction variables were determined by a univariate optimization strategy to obtain maximum extraction performance.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!