Intensity- and time-based strategies for micro/nano-sizing via single-particle ICP-mass spectrometry: A comparative assessment using Au and SiO as model particles.

Background: Single-particle ICP-mass spectrometry (SP-ICP-MS) is a powerful method for micro/nano-particle (MNP) sizing. Despite the outstanding evolution of the technique in the last decade, most studies still rely on traditional approaches based on (1) the use of integrated intensity as the analytical signal and (2) the calculation of the transport efficiency (TE). However, the increasing availability of MNP standards and advancements in hardware and software have unveiled new venues for MNP sizing, including TE-independent and time-based approaches.

Tracing isotopically labeled selenium nanoparticles in plants via single-particle ICP-mass spectrometry.

Agronomic biofortification using selenium nanoparticles (SeNPs) shows potential for addressing selenium deficiency but further research on SeNPs-plants interaction is required before it can be effectively used to improve nutritional quality. In this work, single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS) was used for tracing isotopically labeled SeNPs (SeNPs) in Oryza sativa L. tissues.

Isotope Dilution Analysis for Particle Mass Determination Using Single-Particle Inductively Coupled Plasma Time-of-Flight Mass Spectrometry: Application to Size Determination of Silver Nanoparticles.

This paper describes methodology based on the application of isotope dilution (ID) in single-particle inductively coupled plasma time-of-flight mass spectrometry (spICP-ToFMS) mode for the mass determination (and sizing) of silver nanoparticles (AgNPs). For this purpose, and considering that the analytical signal in spICP-MS shows a transient nature, an isotope dilution equation used for online work was adapted and used for the mass determination of individual NPs. The method proposed measures NP isotope ratios in a particle-to-particle approach, which allows for the characterization of NP mass (and size) distributions and not only the mean size of the distribution.

An Approach Based on an Increased Bandpass for Enabling the Use of Internal Standards in Single Particle ICP-MS: Application to AuNPs Characterization.

This paper proposes a novel approach to implement an internal standard (IS) correction in single particle inductively coupled plasma mass spectrometry (SP ICP-MS), as exemplified for the characterization of Au nanoparticles (NPs) in complex matrices. This approach is based on the use of the mass spectrometer (quadrupole) in bandpass mode, enhancing the sensitivity for the monitoring of AuNPs while also allowing for the detection of PtNPs in the same measurement run, such that they can serve as an internal standard. The performance of the method developed was proved for three different matrices: pure water, a 5 g L NaCl water solution, and another water solution containing 2.

Living in a transient world: ICP-MS reinvented time-resolved analysis for monitoring single events.

After 40 years of development, inductively coupled plasma-mass spectrometry (ICP-MS) can hardly be considered as a novel technique anymore. ICP-MS has become the reference when it comes to multi-element bulk analysis at (ultra)trace levels, as well as to isotope ratio determination for metal(loid)s. However, over the last decade, this technique has managed to uncover an entirely new application field, providing information in a variety of contexts related to the individual analysis of single entities (, nanoparticles, cells, or micro/nanoplastics), thus addressing new societal challenges.

A novel approach for adapting the standard addition method to single particle-ICP-MS for the accurate determination of NP size and number concentration in complex matrices.

This paper presents a novel approach, based on the standard addition method, for overcoming the matrix effects that often hamper the accurate characterization of nanoparticles (NPs) in complex samples via single particle inductively coupled plasma mass spectrometry (SP-ICP-MS). In this approach, calibration of the particle size is performed by two different methods: (i) by spiking a suspension of NPs standards of known size containing the analyte, or (ii) by spiking the sample with ionic standards; either way, the measured sensitivity is used in combination with the transport efficiency (TE) for sizing the NPs. Moreover, such transport efficiency can be readily obtained from the data obtained via both calibration methods mentioned above, so that the particle number concentration can also be determined.

On the effect of using collision/reaction cell (CRC) technology in single-particle ICP-mass spectrometry (SP-ICP-MS).

In this work, the effects of using collision/reaction cell (CRC) technology in quadrupole-based ICP-MS (ICP-QMS) instrumentation operated in single-particle (SP) mode have been assessed. The influence of (i) various CRC gases, (ii) gas flow rates, (iii) nanoparticle (NP) sizes and (iv) NP types was evaluated using Ag, Au and Pt NPs with both a traditional ICP-QMS instrument and a tandem ICP-mass spectrometer. It has been shown that using CRC technology brings about a significant increase in the NP signal peak width (from 0.

Detecting paraprotein interference on a direct bilirubin assay by reviewing the photometric reaction data.

Background: The direct bilirubin (D-Bil) assay on the AU Beckman Coulter instrumentation can be interfered by paraproteins, which may result in spurious D-Bil results. In a previous work, we took advantage of this fact to detect this interference, thus helping with the identification of patients with unsuspected monoclonal gammopathies. In this work, we investigate the possibility to detect interference based on the review of the photometric reactions, regardless of the D-Bil result.

Serum copper concentrations in hospitalized newborns.

Background: Low serum Cu and ceruloplasmin (Cp) concentrations in newborns can be the first indication of a severe Cu deficient intake or, alternatively, of genetic diseases affecting Cu metabolism. However, Cu and Cp concentrations can also be influenced by other variables that render their quantitative results difficult to interpret. Therefore, it is necessary to identify these variables and stratify Cu and Cp concentrations according to these altering factors.

Determination of chlorine via the CaCl molecule by high-resolution continuum source graphite furnace molecular absorption spectrometry and direct solid sample analysis.

This work investigates the possibilities of high-resolution continuum source graphite furnace molecular absorption spectrometry for the direct determination of Cl in solid samples via the CaCl molecule and measurement of its molecular absorption. The method proposed is based on addition of 400µg Ca as molecule-forming reagent and of 20µgPd as chemical modifier, which helps to stabilize the analyte and enhances sensitivity. The molecular spectrum for CaCl offers different lines with different limits of detection and linear ranges, which permitted to analyze solid samples with different Cl contents.

Analytical interference by monoclonal immunoglobulins on the direct bilirubin AU Beckman Coulter assay: the benefit of unsuspected diagnosis from spurious results.

Background: Monoclonal (M) components can interfere with the direct bilirubin (D-Bil) assay on the AU Beckman Coulter instrumentation and produce spurious results, such as D-Bil values greater than total bilirubin (T-Bil) or very low/negative D-Bil values. If properly detected, this interference may uncover undiagnosed patients with monoclonal gammopathy (MG).

Methods: We investigated the interference rate on the D-Bil AU assay in serum samples known to contain M proteins along with their isotype and described the protocol set up in our laboratory to help with the diagnosis of MG based on D-Bil spurious results as first indication.

Serum sample containing endogenous antibodies interfering with multiple hormone immunoassays. Laboratory strategies to detect interference.

Objectives: Endogenous antibodies (EA) may interfere with immunoassays, causing erroneous results for hormone analyses. As (in most cases) this interference arises from the assay format and most immunoassays, even from different manufacturers, are constructed in a similar way, it is possible for a single type of EA to interfere with different immunoassays. Here we describe the case of a patient whose serum sample contains EA that interfere several hormones tests.

Lead screening in DBS by solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry: application to newborns and pregnant women.

Background: DBS have become a clinical specimen especially adequate for establishing home-based collection protocols. In this work, high-resolution continuum source graphite furnace atomic absorption spectrometry is evaluated for the direct monitoring of Pb in DBS, both as a quantitative tool and a screening method.

Methodology: The development of the screening model is based on the establishment of the unreliability region around the threshold limits, 100 or 50 μg l(-1).

Cross-sectional relationship between chronic stress and mineral concentrations in hair of elementary school girls.

Chronic stress exposure is associated with diverse negative health outcomes. It has been hypothesised that stress may also negatively affect the body's mineral status. This study investigates the association between chronic stress and long-term mineral concentrations of calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), phosphorus (P) and zinc (Zn) in scalp hair among elementary school girls.

Hair minerals and metabolic health in Belgian elementary school girls.

Literature has repeatedly shown a relationship between hair minerals and metabolic health, although studies in children are currently lacking. This study aims to investigate hair levels of calcium (Ca), copper (Cu), magnesium (Mg), iron (Fe), phosphorus (P), and zinc (Zn) and their association with (1) overweight/obesity and (2) metabolic health in Flemish elementary school girls between 5 and 10 years old. Two hundred eighteen girls participated in this study as part of the baseline ChiBS project.

Copper and tin isotopic analysis of ancient bronzes for archaeological investigation: development and validation of a suitable analytical methodology.

Although in many cases Pb isotopic analysis can be relied on for provenance determination of ancient bronzes, sometimes the use of "non-traditional" isotopic systems, such as those of Cu and Sn, is required. The work reported on in this paper aimed at revising the methodology for Cu and Sn isotope ratio measurements in archaeological bronzes via optimization of the analytical procedures in terms of sample pre-treatment, measurement protocol, precision, and analytical uncertainty. For Cu isotopic analysis, both Zn and Ni were investigated for their merit as internal standard (IS) relied on for mass bias correction.

Direct trace-elemental analysis of urine samples by laser ablation-inductively coupled plasma mass spectrometry after sample deposition on clinical filter papers.

Collection of biological fluids on clinical filter papers shows important advantages from a logistic point of view, although analysis of these specimens is far from straightforward. Concerning urine analysis, and particularly when direct trace elemental analysis by laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) is aimed at, several problems arise, such as lack of sensitivity or different distribution of the analytes on the filter paper, rendering obtaining reliable quantitative results quite difficult. In this paper, a novel approach for urine collection is proposed, which circumvents many of these problems.

Mineral concentrations in hair of Belgian elementary school girls: reference values and relationship with food consumption frequencies.

Although evidence suggests that hair elements may reflect dietary habits and/or mineral intake, this topic remains controversial. This study therefore presents age-specific reference values for hair concentrations of Ca, Cu, Fe, Na, Mg, P and Zn using the LMS method of Cole, and investigates the relationship between dietary habits (i.e.

A nuclear magnetic resonance (1H and 13C) and isotope ratio mass spectrometry (delta13C, delta2H and delta18O) study of Andalusian olive oils.

We have determined delta(13)C, delta(2)H and delta(18)O isotopic abundances in Andalusian olive oils. In addition, the fatty acid composition and the distribution of isomers at positions 1,3 and 2 of glycerol were determined by (1)H and (13)C nuclear magnetic resonance (NMR) spectroscopy, respectively. Isotopic results obtained for four series of oil samples extracted from olives harvested in the 2004/05 and 2005/06 seasons are discussed in terms of olive variety, ripeness, geographical origin, fatty acid composition and growing altitude.

A study on the potential application of natural phosphate in photocatalytic processes.

In an attempt at increasing surface area of the resulting solids, different titanium-based systems were synthesized on natural phosphate through the sol-gel process using diverse ageing conditions (reflux, magnetic stirring, sonication or microwaves) and tested for gas-phase selective photooxidation of propan-2-ol. The best results were obtained for the system aged under ultrasounds which was ascribed to its lower band-gap energy. Moreover, the synthesis of TiO(2) on natural phosphate seemed to produce retardation in crystallization as well as a change in titanium and phosphorus electronic environments (as determined by XPS) which in the case of the sonicated system resulted in an improved catalytic behavior as compared to pure titania.

Electrothermal vaporization-inductively coupled plasma-mass spectrometry: A versatile tool for tackling challenging samples - A critical review.

In this review, the literature on the subject of electrothermal vaporization-inductively coupled plasma-mass spectrometry (ETV-ICP-MS) published during the last decade is reviewed with a double purpose: an evaluation of the possibilities of this technique for dealing with very challenging analytical applications on the one hand, and the establishment of a reference guide for method development in ETV-ICP-MS on the other. First, a brief introduction, pointing out the milestones in the development of the technique will provide the reader with a better understanding of the present situation of ETV-ICP-MS and its future perspective. After a section on the basic processes occurring in the furnace and during analyte transport, a guide for method development for challenging analytical applications is proposed, based on the existing literature.

Solid sampling-graphite furnace atomic absorption spectrometry for the direct determination of silver at trace and ultratrace levels.

In this work, the possibilities of solid sampling-graphite furnace atomic absorption spectrometry for the direct determination of silver in solid samples of very different nature (a biological sample, a soil, an ore concentrate and a polymer) and showing substantial differences in their analyte content (from approximately, 40 ng g(-1) up to 350 microg g(-1)) have been evaluated, the goal always being to develop fast methods, only relying on the use of aqueous standards for calibration. Different factors had to be taken into account in order to develop suitable procedures for all the samples under investigation. Among the most important ones, the following can be mentioned: (i) optimization of the temperature program in order to selectively atomize the analyte; (ii) the use of chemical modifiers (such as Pd or HNO3), depending on the sample characteristics; (iii) appropriate wavelength, argon flow and sample mass selection (depending on the analyte content); (iv) the use of 3-field mode Zeeman-effect background correction in order to further expand the linear range up to 1000 ng of Ag, which was needed for analysis of the sample showing the highest Ag content (polypropylene).

Solid sampling-graphite furnace atomic absorption spectrometry for the direct determination of boron in plant tissues.

In this work, the potential of graphite furnace atomic absorption spectrometry for the direct determination of B in plant tissues has been investigated. Three certified reference materials (NIST SRM 1570a spinach leaves, NIST SRM 1573a tomato leaves and BCR CRM 679 white cabbage) were selected for this study, the goal always being to develop a fast procedure that could be robust enough to provide a satisfactory performance for all of them, without any modifications in the conditions applied. The use of a suitable chemical modifier was found to be essential for obtaining a reproducible and sufficiently sensitive signal for boron solutions.

Oxygen-18 measurement of Andalusian olive oils by continuous flow pyrolysis/isotope ratio mass spectrometry.

We report a method for the determination of delta(18)O isotopic abundance in olive oils. The results obtained by applying the method to various Andalusian oil samples obtained in the 2004/05 and 2005/06 seasons are discussed in relation to olive variety, geographical origin, climate and ripeness index. Application of the method to samples of assured varietal purity exposed the influence of olive variety and origin but not of the ripeness index.

Poly(ethylene oxide)-based surfactants as templates for the synthesis of mesoporous silica materials.

Various mesoporous silica solids were prepared by using poly(ethylene oxide)-based surfactants as templates in a neutral, fluoride, or moderately acidic medium, and their properties examined by different physical techniques. Precipitation in an acid or neutral medium provided materials of pore size in between those of micropores and mesopores irrespective of the molecular size of the surfactant. On the other hand, syntheses in a fluoride-containing medium yielded mesoporous materials with pore diameters over the range 36-84 A that increased with increasing surfactant size.