Search results for "Trace analysis"

Evaluation by HPLC-UV of Polar Pesticides in Rice Fields

1999

Pesticides and Herbicides: Residue Determination

2016

Pesticide and herbicide residue determination in food is becoming an especially imperative and challenging issue. Commonly, it involves the simultaneous trace analysis of hundreds of compounds belonging to many chemical classes. This article provides a review of the current status of the routine methods in the monitoring and control of these residues and discusses the analytic problems arising at each stage of the procedure. The role of mass spectrometry in screening, identification, and confirmation of target and nontarget pesticides is highlighted. Consideration is given to new developments and future trends.

Resonance ionization mass spectrometry for trace analysis of long-lived radionuclides

2008

Resonance ionization mass spectrometry (RIMS) is a sensitive and selective method for the determination of extremely low abundances of long-lived radionuclides. The detection limits are about 106 atoms per sample and an isotopic selectivity up to 1013 has been achieved. The potential of RIMS using different experimental arrangements is outlined for the determination of isotope ratios and lowest abundances of long-lived radioisotopes of interest like 238–244Pu, 90Sr, and 41Ca. Recent developments in improving detection limits and the spatial resolution of this technique are briefly discussed.

Dividing Responsibility for Care : Tracing the Ethics of Care in Local Care Strategies

2020

This article analyses local care policies through the lens of the feminist ethics of care. The focus is on the normative understandings regarding care that emerge in local care strategy documents and how these understandings relate with the concept of ‘responsibility’. In this article, strategies published by the municipality of Jyväskylä, Finland, between the years 2008 and 2016, are analysed using Trace analysis. The research questions are: How is the division of responsibility regarding care among different actors constructed in the strategies? How do the roles assigned to these different actors accord with the principles of ethics of care? The findings show that the documents emphasise …

Analysis of Contact Traces of Cannabis by In-Tube Solid-Phase Microextraction Coupled to Nanoliquid Chromatography

2018

Because of its inherent qualities, in-tube solid-phase microextraction (IT-SPME) coupled on-line to nanoliquid chromatography (nanoLC) can be a very powerful tool to address the new challenges of analytical laboratories such as the analysis of traces of complex samples. This is the case of the detection of contact traces of drugs, especially cannabis. The main difficulties encountered in the analysis of traces of cannabis plants on surfaces are the low amount of sample available (typically &lt

Solid-phase extraction of quaternary ammonium herbicides

2000

This paper highlights recent advances in the solid-phase extraction (SPE) of quaternary ammonium herbicides in water, soil, plant and biological samples. After a brief introduction summarizing the properties of quaternary ammonium herbicides and the difficulties involved in measuring them, attention is paid primarily to solid supports used for isolation and concentration, pre-treatments required for the different matrices, and eluents applied for quantitative desorption of these analytes. The determination techniques used after SPE and applications of the proposed SPE methodology are also briefly discussed.

Spectrophotometric determination of phenol and resorcinol by reaction with p-aminophenol

1993

Abstract Based on the reaction with p-aminophenol, a series of procedures have been developed for the spectrophotometric determination of phenol and resorcinol. Three basic approaches have been studied: (i) a batch procedure, using the dissolved oxygen as oxidant, (ii) a stopped-flow procedure by use of KIO4 as oxidant and (iii) a flow injection (FI) procedure developed in the presence of KIO4. Phenol can be accurately determined at 626 nm, in the stopped-flow mode, after a reaction time of 45 min in 0.005M NaOH, 0.004M KIO4 and 500 μg/ml of PAP. The development of a manifold, which incorporates a sample parking, is a convenient approach which makes it possible to measure, in the stopped-fl…

Trace Analysis of the Radionuclides90Sr and89Sr in Environmental Samples I: Laser Mass Spectrometry

1995

Resonance ionization mass spectroscopy for nuclear research and trace analysis

1987

Resonance ionization mass spectroscopy (RIMS) has been applied, firstly, to a study of the nuclear properties of short-lived Au isotopes at the on-line isotope separator ISOLDE at CERN and, secondly, to a trace-analysis experiment of Pu.

Evaluation of Thin Film Microextraction for trace elemental analysis of liquid samples using LIBS detection

2021

An analytical methodology based in the combination of Thin Film Microextraction with Laser-induced Breakdown Spectroscopy (TFME-LIBS) was investigated, for the first time, for detection of Cu, Cr, Ni and Pb in aqueous solutions. In this methodology, the analytes were extracted in a thin film of adsorbent material deposited on a solid support, which was introduced in the sample to analyse. After extraction, the analytes retained in the adsorbent were analysed by LIBS. In order to obtain adsorbent films useful for the microextraction step, two different experimental procedures for film generation, denoted as Drop Casting Deposition and Mould Deposition, were evaluated. In both cases, graphene…