A novel separation and preconcentration methodology based on direct immersion dual-drop microextraction for speciation of inorganic chromium in environmental water samples.

In this study, for the first time, a novel separation and preconcentration method of direct immersion dual-drop microextraction (DIDDME) was proposed for the species of inorganic chromium (Cr(III) and Cr(VI)) followed by graphite furnace atomic absorption spectrometry detection. The methodology is based on that two organic drops hold on the needle tips of microsyringes were concurrently immersed in a stirred sample solution. Each drop contains a chelating reagent, which can react with a specific species under the same pH value.

Direct immersion dual-drop microextraction for simultaneous separation and enrichment of Cr(III) and Cr(IV) in food samples prior to graphite furnace atomic absorption spectrometry detection.

Non-chromatographic speciation methods generally involve speciation conversion, which may cause sample contamination, analysis errors and tedious operations. In this work, a direct immersion dual-drop microextraction (DIDDME) was firstly developed for separation and preconcentration of Cr(III) and Cr(VI). In DIDDME, two organic drops on needle tips of microsyringes were concurrently immersed in a stirred sample solution.

In-syringe solid phase extraction and in-syringe vortex-assisted solidified floating organic drop microextraction of Sb(III) and Sb(V) in rice wines with determination by graphite furnace atomic absorption spectrometry.

The current non-chromatographic speciation methods generally involve the conversion of different species by oxidation/reduction reactions, which may cause inherent problems such as contamination risk, time consumption and complex operations. In this work, in-syringe solid phase extraction (IS-SPE) was combined with in-syringe vortex-assisted solidified floating organic drop microextraction (IS-VA-SFODME) for the detection of Sb(V) and Sb(III) in rice wines by graphite furnace atomic absorption spectrometry. Firstly, IS-SPE involved the use of ZnFeO nanotubes as the sorbent for the isolation and enrichment of Sb(V) and removal of the matrix components such as ethanol, pigment, sugars and carbohydrates.

Magnetic dispersive micro-solid phase extraction coupled with dispersive liquid-liquid microextraction followed by graphite furnace atomic absorption spectrometry for quantification of Se(IV) and Se(VI) in food samples.

In this work, magnetic dispersive micro-solid phase extraction (MDMSPE) coupled with dispersive liquid-liquid microextraction (DLLME) was developed for Se(IV) and Se(VI) followed by graphite furnace atomic absorption spectrometry. MDMSPE involved the use of magnetic ZnFeO nanotubes for adsorbing Se(VI). The sorbent was isolated from aqueous phase by using an external magnetic field instead of tedious centrifugation or filtration.

Determination of Mn(II) and Mn(VII) in beverage samples using magnetic dispersive micro-solid phase extraction coupled with solidified floating organic drop microextraction followed by graphite furnace atomic absorption spectrometry.

Magnetic dispersive micro-solid phase extraction (MDMSPE) was coupled with solidified floating organic drop microextraction (SFODME) for direct separation and preconcentration of Mn(II) and Mn(VII) before graphite furnace atomic absorption spectrometry determination. MDMSPE involved use of magnetic ZnFeO nanotubes for adsorbing Mn(VII). Sorbent was isolated from aqueous phase by an external magnet.

Fibrous g-C3N4@Tio2 Nanocomposites-Based Dispersive Micro-Solid Phase Extraction for Chromium Speciation in Cow Milk by ICP-MS after Digestion Treatment with Artificial Gastric Juice.

Background: Chromium is an interesting element because its toxicity depends on its speciation. Thus, knowledge of Cr speciation in cow milk is essential to human health.

Objective: This study aims to achieve real bioaccessible species in cow milk, including Cr(III), Cr(VI), residual, digestible, and total Cr.

Magnetic ZnFeO nanotubes for dispersive micro solid-phase extraction of trace rare earth elements prior to their determination by ICP-MS.

Magnetic ZnFeO nanotubes (ZFONTs) with numerous pores on their walls were synthesized and characterized. They are shown to be a viable sorbent for dispersive micro-solid phase extraction of the trivalent ions of rare earth elements (REEs), specifically of lanthanum, praseodymium, europium, gadolinium, holmium and ytterbium. The specific surface area of ZFONTs is large (57 m⋅g) and much bigger than that of ZnFeO nanoparticles (16 m⋅g).

Dual extraction based on solid phase extraction and solidified floating organic drop microextraction for speciation of arsenic and its distribution in tea leaves and tea infusion by electrothermal vaporization ICP-MS.

A dual extraction based on solid phase extraction (SPE) and solidified floating organic drop microextraction (SFODME) was developed for As species in tea leaves and tea infusion by electrothermal vaporization inductively coupled plasma mass spectrometry, including total, suspended, soluble, organic and inorganic As as well as As(III) and As(V). In SPE step, titanium dioxide nanotubes were used for preconcentration of analytes and removal of sample matrix. Elution solution from SPE was employed for further preconcentration and separation of analytes with SFODME.

Solidified floating organic drop microextraction for speciation of selenium and its distribution in selenium-rich tea leaves and tea infusion by electrothermal vapourisation inductively coupled plasma mass spectrometry.

Solidified floating organic drop microextraction was combined with electrothermal vapourisation inductively coupled plasma mass spectrometry for Se species in Se-rich tea leaves and tea infusion, including total, suspended, soluble, organic and inorganic Se as well as Se(IV) and Se(VI). Ammonium pyrrolidinedithiocarbamate was used as both chelating reagent and chemical modifier in this study. Se(IV) and Se(VI) were separated at pH range of 2.

Speciation of chromium and its distribution in tea leaves and tea infusion using titanium dioxide nanotubes packed microcolumn coupled with inductively coupled plasma mass spectrometry.

Titanium dioxide nanotubes (TDNTs) were used as a solid phase extraction adsorbent for chromium species by a packed microcolumn coupled with inductively coupled plasma mass spectrometry (ICP-MS), including total, suspended and soluble chromium as well as Cr(III) and Cr(VI) in tea leaves and tea infusion. The experimental results indicated that Cr(III) was quantitatively retained on TDNTs in the pH range of 5.0-8.

Solid-phase extraction of Cu, Co and Pb on oxidized single-walled carbon nanotubes and their determination by inductively coupled plasma mass spectrometry.

A novel method using a microcolumn packed with single-walled carbon nanotubes (SWNTs) as a new adsorption material was developed for the preconcentration of trace Cu, Co and Pb in biological and environmental samples prior to their determination by inductively coupled plasma mass spectrometry (ICP-MS). SWNTs oxidized with concentrated nitric acid have been proved to possess an exceptional adsorption capability for the analytes due to their surface functionalization. The adsorption behaviors of the analytes on SWNTs under dynamic conditions were studied systematically.

Speciation analysis of inorganic arsenic in natural water by carbon nanofibers separation and inductively coupled plasma mass spectrometry determination.

In this paper, carbon nanofibers (CNFs) as a novel solid phase extraction sorbent were developed for speciation preconcentration and separation of inorganic arsenic species As(III) and As(V) prior to determination by inductively coupled plasma mass spectrometry (ICP-MS). It was found that during all the steps of the separation, As(III) was selectively sorbed on the microcolumn packed with CNFs within a pH range of 1.0-3.

Application of low temperature electrothermal vaporization ICP-AES for determination of refractory yttrium with 1-(2-pyridylazo)-2-naphthol as chemical modifier.

A low temperature electrothermal vaporization inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES) method was developed for the determination of the refractory yttrium, using 1-(2-pyridylazo)-2-naphthol (PAN) as chemical modifier. The trace yttrium was vaporized as PAN complex into plasma from a graphite furnace at a comparatively low temperature of 1200 degrees C. The operation conditions were optimized, and the vaporization behavior of Y-PAN chelate and the main factors affecting the determination were investigated in detail.

[Determination of gold in geological sample by inductively coupled plasma mass spectrometry after carbon nanofibers separation and preconcentration].

A novel method for the determination of Au by inductively coupled plasma mass spectrometry (ICP-MS) is described. Au can be separated and preconcentrated with a micro-column packed with carbon nanofibers as an adsorption material. The adsorption and elution behaviors of Au3+ on carbon nanofibers were systematically investigated under dynamic conditions.

Use of a microcolumn packed with modified carbon nanofibers coupled with inductively coupled plasma mass spectrometry for simultaneous on-line preconcentration and determination of trace rare earth elements in biological samples.

In this work, a new method was developed for the determination of trace rare earth elements (REEs) in biological samples by inductively coupled plasma mass spectrometry (ICP-MS) after preconcentration on a microcolumn packed with modified carbon nanofibers (CNFs). CNFs oxidized with nitric acid have been proved to possess an exceptional adsorption capability for REEs due to their surface functionalization. The effects of the experimental parameters, including pH, sample flow rate and volume, elution solution and interfering ions, on the recoveries of the analytes have been investigated systematically.

Direct inductively coupled plasma-atomic emission spectrometry analysis of trace elements in muscle tissues of hairtail using electrothermal vaporization with slurry sampling.

A procedure for direct determination of trace elements in muscle tissue of hairtail was developed using inductively coupled plasma-atomic emission spectrometry and electrothermal vaporization with slurry sampling. Due to use of polytetrafluoroethylene as the chemical modifier, the vaporization behaviors of analytes from the slurry and the aqueous standard solutions were very similar. In this case, the aqueous standards could be used for the calibration of slurry samples.

[Slurry sampling for direct determination of trace cadmium in amber by graphite furnace atomic absorption spectrometry].

A method for the direct determination of trace cadmium in amber by graphite furnace atomic absorption spectrometry (GFAAS) with slurry sampling was described. Palladium nitrate was used as a matrix modifier to eliminate the interference. Slurry stability and the influences of the matrix modifier, ashing/atomization temperature and coexistent ions on analytical signals were investigated in detail.