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Gd-based contrast agents (GBCAs) are frequently administered to patients for magnetic resonance imaging to enhance tissue contrasts. After examination, they are excreted and enter surface waters via local wastewater treatment plants' effluents where they lead to anthropogenic Gd anomalies in the environment of metropolitan areas with developed healthcare. This work presents the speciation analysis of GBCAs in water samples from Australia by targeting individual GBCAs in effluent, river and seawater samples obtained from New South Wales (Sydney area), the Northern Territory (Alice Springs) and Victoria (Melbourne area). A method based on hydrophilic interaction liquid chromatography (HILIC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS) provided rapid separation and quantification of four common GBCAs in under three minutes. To improve the sensitivity, ion extraction and transport processes were optimised and the quadrupole mass filter was operated with an increased mass bandpass, decreasing limits of detection to between 18 and 24 ng L−1 for individual GBCAs. This allowed detection of Gd-DOTA, Gd-BT-DO3A and Gd-DTPA-BMA at concentrations of up to 160 ng L−1 in water samples collected from rivers within the proximity of effluents of local wastewater treatment plants. The analysis of GBCAs in oceanic sea water required the development of a novel automated micro-solid phase extraction (μSPE) method for matrix elimination and analyte pre-concentration enabling the detection of Gd-DOTA and Gd-BT-DO3A. [ABSTRACT FROM AUTHOR]

Standard preparation for elemental bio-imaging by laser ablation-inductively coupled plasma-mass spectrometry is confounded by the chemical and physical differences between standard and sample matrices. These differences lead to variable ablation, aerosol generation and transportation characteristics and must be considered when designing matrix-matched standards for reliable calibration and quantification. The ability to precisely mimic sample matrices is hampered due to the complexity and heterogeneity of biological tissue and small variabilities in standard matrices and sample composition often negatively impact accuracy, precision and robustness. Furthermore, cumbersome preparation protocols may limit reproducibility and traceability. This work presents novel facile methods for the preparation of gelatine standards using both commercial and laboratory-made moulds. Surface roughness, thickness and robustness of the mould-prepared standards were compared against cryo-sectioned gelatine and homogenised brain tissue standards. The mould-prepared standards had excellent thickness accuracy and signal precision which allowed robust quantification, were easier to prepare and therefore easier to reproduce. We also compared gelatine standards prepared from a variety of animal sources and discuss their suitability to calibrate low level elemental concentrations. Finally, we present a simple method to remove background metals in gelatine using various chelating resins to increase the dynamic calibration range and to improve limits of analysis. [ABSTRACT FROM AUTHOR]

The biological function of minor and trace elements is ordinarily determined by their association with specific proteins, peptides and other biomolecules. Therefore, measuring the total elemental content of a biological sample provides limited information, particularly when a specific effect is due to an individual metal-protein complex. Speciation of metalloproteins, heteroatom-containing molecules or other compounds tagged with an exogenous metal can be used to overcome this limitation. A range of chromatographic separation techniques with on-line elemental detection using inductively coupled plasma-mass spectrometry (ICP-MS) have been applied to the biosciences, and each technique has intrinsic features that must be considered when designing speciation experiments. This tutorial review provides an overview of speciation in the biosciences, highlighting the unique abilities and limitations encountered. A selection of recent technical advances and new applications, the challenges of sample preparation and implementation of new technical developments are discussed, as well as the future directions of technology that is rapidly gaining a foothold in the contemporary biochemistry laboratory. [ABSTRACT FROM AUTHOR]

The Agilent Chip Cube Interface is a microfluidic chip-based technology originally designed for nanospray molecular mass spectrometry in which the sample enrichment, nano-column, tubing, connectors and spray tip were integrated into a single biocompatible chip. Here we describe the hyphenation of the Chip Cube Interface to ICP-MS via modification of the standard HPLC chip design and a new total consumption nebuliser suitable for flow rates as low as 300 nL min −1 . The potential of the instrument to eliminate common nanoLC – ICP-MS shortcomings such as leaks, blockages and band-broadening was demonstrated via analysis of cyanocobalamin in equine plasma. The method was linear over three orders of magnitude with an r 2 of 0.9999, the peak area repeatability was 1.9% (n = 7), and the detection limit was 14 ng mL −1 . This novel configuration of the Chip Cube Interface coupled to ICP-MS is a suitable platform for the analysis of biomolecules associated with trace metals and speciation applications. [ABSTRACT FROM AUTHOR]

Gadolinium (Gd)-based magnetic resonance imaging (MRI) contrasting agents interfere with the determination of selenium (Se) when analysed by single quadrupole inductively coupled plasma-mass spectrometry (ICP-MS). This paper demonstrates that an ICP-triple quadrupole-MS (ICP-QQQ-MS) with oxygen mass shift overcomes Gd++ interference on Se+ and mitigates typically encountered matrix and spectral based interferences. Normal human serum was diluted in a solution containing isopropanol, EDTA, NH4OH and Triton X-100. Samples were unspiked (control) serum; serum spiked with 0.127 μmol L−1 Se or 127 μmol L−1 Gd; and serum spiked with both 0.127 μmol L−1 Se and 127 μmol L−1 Gd. Consideration of collision/reaction gases and conditions for interference mitigation included helium (He); a ‘low’ and ‘high’ hydrogen (H2) flow, and oxygen (O2). The instrument tune for O2 was optimised for effective elimination of interferences via a mass shift reaction of Se+ to SeO+. The ICP-QQQ-MS was capable of detecting trace (＞9.34 nmol L−1) levels of Se in serum in the presence of Gd in our simulated post-MRI serum sample. The multi-tune capabilities of the ICP-QQQ-MS may be adapted to eliminate other specific isobaric interferences that cause false positive results in other analyses where the analyte is confounded by doubly charged and/or polyatomic species. [ABSTRACT FROM AUTHOR]

Over 7500 oil and gas structures (e.g. oil platforms) are installed in offshore waters worldwide and many will require decommissioning within the next two decades. The decision to remove such structures or turn them into reefs (i.e. ‘rigs-to-reefs’) hinges on the habitat value they provide, yet this can rarely be determined because the residency of mobile species is difficult to establish. Here, we test a novel solution to this problem for reef fishes; the use of otolith (earstone) properties to identify oil structures of residence. We compare the otolith microchemistry and otolith shape of a site-attached coral reef fish ( Pseudanthias rubrizonatus ) among four oil structures (depth 82–135 m, separated by 9.7–84.2 km) on Australia's North West Shelf to determine if populations developed distinct otolith properties during their residency. Microchemical signatures obtained from the otolith edge using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) differed among oil structures, driven by elements Sr, Ba and Mn, and to a lesser extent Mg and Fe. A combination of microchemical data from the otolith edge and elliptical Fourier (shape) descriptors allowed allocation of individuals to their ‘home’ structure with moderate accuracy (overall allocation accuracy: 63.3%, range: 45.5–78.1%), despite lower allocation accuracies for each otolith property in isolation (microchemistry: 47.5%, otolith shape: 45%). Site-specific microchemical signatures were also stable enough through time to distinguish populations during 3 separate time periods, suggesting that residence histories could be recreated by targeting previous growth zones in the otolith. Our results indicate that reef fish can develop unique otolith properties during their residency on oil structures which may be useful for assessing the habitat value of individual structures. The approach outlined here may also be useful for determining the residency of reef fish on artificial reefs, which would assist productivity assessments of these habitats. [ABSTRACT FROM AUTHOR]