The metamorphosis of analytical chemistry.

Defining analytical chemistry as the measurement of isolated compositional features in a selected study object ignores the unique perspective that analytical chemists bring to twenty-first century science and society. In this feature article, we will discuss some of the existing preconceptions and misinterpretations of analytical chemistry that occur at present and will tackle them from the more up-to-date perspective of science in the Big Data Era. This will place their influence in context while simultaneously enlarging the scope of the discipline analytical chemistry to its well-deserved prevalent position in present-day science and technology.

History and present status of imaging analysis.

In this tutorial review we give a concise and general overview of the development of imaging analytical techniques from its early stages in the late 1950s up to the present. Analytical techniques that are available for the characterization of the atomic and molecular composition as well as the structure at the bulk level often fail for the analysis of heterogeneous materials. Over the last 50 years a number of specialized analytical techniques were developed - or adapted from existing techniques - that, with time, matured into powerful tools for visualizing structural and compositional heterogeneity in nanotechnology and for the study of natural objects.

Cytosolic distribution of Cd, Cu and Zn, and metallothionein levels in relation to physiological changes in gibel carp (Carassius auratus gibelio) from metal-impacted habitats.

In the present study the impact of environmental metal contamination in gibel carp (Carassius auratus gibelio) was investigated coupling disturbances in subcellular metal distribution to effect biomarkers. Gibel carp were caught at six different sampling sites in Flanders (Belgium), characterized by different degrees in environmental metal contamination. Tissue Cd, Cu and Zn concentrations and total metallothioneon (MT) levels were determined in gills, liver and kidney.

Static secondary ion mass spectrometry (S-SIMS) for the characterization of surface components in mineral particulates.

The feasibility of static secondary ion mass spectrometry (S-SIMS) for the detection of molecule specific information from complex materials, such as natural clay and soil samples, has been investigated. Ion trap (IT), as well as triple quadrupole (TQ) instruments, have been used for mass analysis. Secondary ion images have been acquired using time-of-flight (TOF) S-SIMS.

A field survey of metal binding to metallothionein and other cytosolic ligands in liver of eels using an on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS).

The effect of metal exposure on the accumulation and cytosolic speciation of metals in livers of wild populations of European eel with special emphasis on metallothioneins (MT) was studied. Four sampling sites in Flanders showing different degrees of heavy metal contamination were selected for this purpose. An on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS) was used to study the cytosolic speciation of the metals.

Determination of trace elements in natural waters by inductively coupled plasma time of flight mass spectrometry after flow injection preconcentration in a knotted reactor.

A flow injection on-line sorption system was developed for the separation and preconcentration of traces of Ag, Cd, Co, Ni, Pb, U and Y from natural water samples with subsequent detection by ICP TOF MS. Simultaneous preconcentration of the analytes was achieved by complexation with the chelating reagent 1-phenyl-3-methyl-4-benzoylpyrazol-5-one immobilized on the inner walls of a (200cm x 0.5mm) PTFE knotted reactor.

Anion-exchange high performance liquid chromatography hyphenated to inductively coupled plasma-isotope dilution-time-of-flight mass spectrometry for speciation analysis of metal complexes with metallothionein isoforms in gibel carp (Carassius auratus gibelio) exposed to environmental metal pollution.

The capability of post-column isotope dilution (ID) combined with anion-exchange HPLC-ICP-time-of-flight (TOF)-MS was for the first time investigated for environmental quality assessment through metal speciation analysis of metallothionein (MT) isoforms in cytosols of gibel carp (Carassius auratus gibelio), used as biomarkers for environmental metal exposure. A full spectral scanning of the biological sample (with 50 microl injection volume) using ICP-TOF-MS in transient mode allowed fast multi-isotope screening of cytosolic metal-containing fractions and to investigate the presence of matrix-induced interferences. The MT cytosolic fraction of liver and kidney of the carp, sampled at three different sampling sites in Belgium, was partially purified using size-exclusion (SE) HPLC.

Feasibility of analyzing molecular pigments in paint layers using TOF S-SIMS.

A first attempt to measure the molecular compositions of pigments in paintings using static SIMS was made. An investigation of pellets of pure pigments such as auripigment and verdigris allowed the detection of numerous high m/z ions useful for molecular identification. Analysis of pigments in embedded paint fragments, on the other hand, only yielded elemental information because of charge build-up and contamination problems.

Effectiveness of leaded petrol phase-out in Tianjin, China based on the aerosol lead concentration and isotope abundance ratio.

The phase-out of leaded petrol has been a measure widely used to reduce atmospheric lead pollution. Since the 1980s, China began to promote unleaded petrol. In order to assess the effectiveness of the measure an isotope fingerprint technique was applied for aerosol samples in the city of Tianjin.

Effect of the interface on separation in multicapillary gas chromatography-based hyphenated techniques for speciation analysis of organometallic compounds.

This paper reports the effect of transfer line (TL) internal diameter (i.d.) on gas chromatographic separation characteristics such as efficiency and speed, when a multicapillary (MC) column is used for speciation analysis of mercury.

Speciation analysis of mercury by solid-phase microextraction and multicapillary gas chromatography hyphenated to inductively coupled plasma-time-of-flight-mass spectrometry.

This paper reports the development of an analytical approach for speciation analysis of mercury at ultra-trace levels on the basis of solid-phase microextraction and multicapillary gas chromatography hyphenated to inductively coupled plasma-time-of-flight mass spectrometry. Headspace solid-phase microextraction with a carboxen/polydimethylsyloxane fiber is used for extraction/preconcentration of mercury species after derivatization with sodium tetraethylborate and subsequent volatilization. Isothermal separation of methylmercury (MeHg), inorganic mercury (Hg2+) and propylmercury (PrHg) used as internal standard is achieved within a chromatographic run below 45 s without the introduction of spectral skew.

Three-dimensional trace element analysis by confocal X-ray microfluorescence imaging.

A three-dimensional (3D) variant of scanning micro X-ray fluorescence (XRF) is described and evaluated at the ID18F instrument of the European Synchrotron Radiation Facility (ESRF). The method is based on confocal excitation/detection using a polycapillary half-lens in front of the energy-dispersive detector. The experimental arrangement represents a significant generalization of regular two-dimensional (2D) scanning micro-XRF and employs a detector half-lens whose focus coincides with that of the focused incoming beam.

Systematization of the mass spectra for speciation of inorganic salts with static secondary ion mass spectrometry.

The analytical use of mass spectra from static secondary ion mass spectrometry for the molecular identification of inorganic analytes in real life surface layers and microobjects requires an empirical insight in the signals to be expected from a given compound. A comprehensive database comprising over 50 salts has been assembled to complement prior data on oxides. The present study allows the systematic trends in the relationship between the detected signals and molecular composition of the analyte to be delineated.

Induction and binding of Cd, Cu, and Zn to metallothionein in carp (Cyprinus carpio) using HPLC-ICP-TOFMS.

The binding of Cd, Cu, and Zn to metallothionein in carp was studied under control and acute Cd exposure scenarios. Carp were exposed to different Cd concentrations for 96 h. Total (Cu, Cd, Zn)-MT levels were determined by the cadmium thiomolybdate saturation assay.

Multi-element speciation of metalloproteins in fish tissue using size-exclusion chromatography coupled "on-line" with ICP-isotope dilution-time-of-flight-mass spectrometry.

An on-line isotope dilution (ID) method in combination with the coupling of size-exclusion high-performance liquid chromatography (SE-HPLC) to an axial inductively coupled plasma time-of-flight mass spectrometer (ICP-TOFMS) was applied to the quantitative speciation of Cu, Zn and Cd in carp and eel cytosols. Quantitative information on the distribution of essential and toxic metals between the different molecular weight fractions in kidney cytosols of control and Cd exposed carp was obtained with species-unspecific spiking by post-column addition of the enriched isotopes 65Cu, 67Zn and 106Cd. The isotope ratios 63Cu/65Cu, 64Zn/67Zn and 114Cd/106Cd, were monitored by ICP-TOFMS in transient signal mode.

A Monte Carlo model for studying the microheterogeneity of trace elements in reference materials by means of synchrotron microscopic X-ray fluorescence.

Synchrotron micro-XRF, a trace-level microanalytical method, allows quantitative study of the nature and degree of heterogeneity of inorganic trace constituents in solid materials with a homogeneous matrix. In this work, the standard reference materials NIST SRM 613, Trace Elements in 1 mm Glass Wafers, and NIST SRM 1577a, Trace Elements in Bovine Liver, are examined at the 10100-ng mass level using X-ray beams of 5-150 microm in diameter. A procedure based on a large number of repeated analyses of small absolute amounts of the SRMs allows calculation of the minimal representative mass of the standard.