Search results for "absorption spectroscopy"

Some observations on the sensitivity of flow-injection techniques for atomic absorption spectrophotometry

1989

Abstract Different strategies for coupling flow-injection manifolds to atomic absorption spectrometers in order to obtain better sensitivity are compared. Using a T-connector interface, different carriers and flow compensation solvents have been assayed in an attempt to improve the sensitivity of flow-injection analysis. Manganese and copper determinations in sewage sludge have been used as a test system and the analytical parameters of both batch and flow-injection methods are compared.

Vapor-phase introduction of alkyltin compounds in atomic absorption spectrophotometry

1990

Abstract Different systems for the introduction of alkyltin compounds in atomic absorption spectrophotometry using the vapor-phase introduction approach have been compared. Samples and standards were introduced in both quartz cell and flame atomizer using a vertical and a horizontal reactor. The better sensitivity was obtained with the quartz cell and the horizontal reactor.

Methylmercury and inorganic mercury determination in fish by cold vapour generation atomic absorption spectrometry

2000

Abstract Given that organic mercury is more dangerous than the inorganic form and that it is converted into methylmercury by biological methylation, we have studied and optimized a simple method for measuring both organic and inorganic mercury contents in fish, using a spectroscopic vapour generation technique, with a sequential reduction of the digested sample with stannous chloride and sodium tetrahydroborate. Prior to applying the method the sample was subjected to alkaline wet digestion. Due to the matrix interferences calibration curves with matrix addition were needed for mercury determinations. The analytical parameters of the method were: linearity from 10 to 200 ng of Hg in the red…

Arsenic content of Spanish cows' milk determined by dry ashing hydride generation atomic absorption spectrometry.

1994

SummaryThe arsenic content of cows' milk consumed in Spain was determined. A procedure using dry ashing hydride generation atomic absorption spectrometry was developed for the purpose. Experimental conditions for the destruction of organic matter were established and an interference study was carried out. The method developed has a detection limit of 0·1 ng/g, a relative SD of 5%, and a recovery (mean ± CSI) of 100 ± 4%. The accuracy of the method was checked by analysis of a certified sample of IAEA milk powder (mean ± CSI: certified, 4·85 ± 0·32 ng/g; found, 5·04 ± 0·81 ng/g). The proposed procedure was used to analyse cows' milk samples. The extremely low arsenic levels found do not pres…

Active alkaline traps to determine acidic-gas ratios in volcanic plumes: Sampling techniques and analytical methods

2014

In situ measurements have been the basis for monitoring volcanic gas emissions for many years and—being complemented by remote sensing techniques—still play an important role to date. Con- cerning in situ techniques for sampling a dilute plume, an increase in accuracy and a reduction of detection limits are still necessary for most gases (e.g., CO2, SO2, HCl, HF, HBr, HI). In this work, the Raschig-Tube tech- nique (RT) is modified and utilized for application on volcanic plumes. The theoretical and experimental absorption properties of the RT and the Drechsel bottle (DB) setups are characterized and both are applied simultaneously to the well-established Filter packs technique (FP) in the …

On-line bi-directional electrostacking for As speciation/preconcentration using electrothermal atomic absorption spectrometry.

2006

A method using bi-directional electrostacking (BDES) in a flow system is presented for As preconcentration and speciation analysis. Some parameters such as electrostacking time and applied voltage, support buffers and their concentrations were investigated. Boric acid plus sodium hydroxide at 0.1mol/l concentration was selected as support buffer to improve the pre-concentration factor (PF) for As(V). An analytical range from 2.0 to 50.0mugl(-1), and 0.35mugl(-1) as limit of detection, when applied 750V for 20min, were achieved. Under these conditions, a pre-concentration factor of 4.8 was obtained. The proposed method was applied to determine As(V) in mineral water and natural water samples…

A Homoleptic Alkynyl‐Ligated [Au 13 Ag 16 L 24 ] 3− Cluster as a Catalytically Active Eight‐Electron Superatom

2020

A new alkynylated cluster [Au13 Ag16 (C10 H6 NO)24 ]3- is prepared by a NaBH4 mediated reduction method. The AuAg clusters are confirmed by sophisticated characterization techniques. It has a unique "Aucenter @Ag12 @Au12 Ag4 " metal framework which is protected by 24 atypical alkyne ligands L (L=C10 H6 NO). The ligands construct a unique type of motif L-(Ag)-Au-(Ag)-L at the cluster interface, where the alkyne (C≡C) group of each L was linked by sharing an Au atom through the σ bonds and each C≡C group was discretely connected to a chemically different Ag atom (Agicosahedral /Agcap ) through π bonds. The electronic and optical properties of [Au13 Ag16 L24 ]3- were studied. DFT characterized…

DOAS Measurements of Iodine Oxides in the Framework of the MAP (Marine Aerosol Production) Project

2007

Defect interaction and local structural distortions in Mg-doped LaGaO3: A combined experimental and theoretical study

2017

A combined experimental and theoretical study of Mg-doped LaGaO3 electrolyte was carried out, with the aim to unveil the interaction between oxygen vacancy (Vo) and perovskite B site cations. LaGaO3 (LG) and LaGa0.875Mg0.125O2.938 (LGM0125) samples were comprehensively characterized by X-ray absorption spectroscopy (XAS) and X-ray diffraction, in order to investigate short- and long-range structures of both undoped and Mg-doped materials. XAS analysis evidenced a preferential Ga-Vo interaction in LGM0125, confirmed by periodic hybrid density functional theory calculations, which were combined with a symmetry-independent classes (SICs) approach in order to (a) obtain a detailed picture of th…

Enhanced chemosensing of ammonia based on the novel molecular semiconductor-doped insulator (MSDI) heterojunctions

2011

Abstract A series of new molecular semiconductor-doped insulator (MSDI) heterojunctions as conductimetric transducers to NH3 sensing were fabricated based on a novel semiconducting molecular material, an amphiphilic tris(phthalocyaninato) rare earth triple-decker complex, Eu2[Pc(15C5)4]2[Pc(OC10H21)8], quasi-Langmuir–Shafer (QLS) film, as a top-layer, and vacuum-deposited and cast film of CuPc as well as copper tetra-tert-butyl phthalocyanine (CuTTBPc) QLS film as a sub-layer, named as MSDIs 1, 2 and 3, respectively. MSDIs 1–3 and respective sub-layers prepared from three different methods were characterized by X-ray diffraction, electronic absorption spectra and current–voltage (I–V) measu…