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The newly negotiated US Mexico Canada Agreement [USMCA in the US, following the TPP tradition of not mentioning Free or Trade] changes very little of significance in NAFTA beyond adding some items already mostly agreed on by all three countries in TPP. The negotiation took so long that the Democrats took control of the US House of Representatives, raising interesting questions about whether they will vote to ratify without changes in labour and environmental enforcement, pharmaceutical IP, and possibly more.

The occurrence of charge transfer and Penning process in glow discharge atomic emission sources can have a profound effect on the specific and overall spectral emission line characteristics of analyte species in these sources. A detailed spectral illustration of several of these effects is presented in this study for Cu, Zn, Ag and Cd with a particular focus on the ionic emission characteristics (i.e. II lines) of these elements. Charge transfer and Penning processes in glow discharge devices are driven by ionic and metastable species generated from the filler gas. Comparison of spectra obtained utilizing different filler gases is particularly effective for revealing the unique and specific excitation pathways for the analyte ions. Detailed high resolution spectra are presented and compared for Cu and Zn (brass) with Ar, Ne or He filler gases and for Ag and Cd with Ar or He as the filler gas illustrating several charge transfer and Penning processes. Unambiguous identification of spectral lines for specific transitions was facilitated by the acquisition of all spectral data utilizing a UV–visible Fourier transform spectrometer. This spectrometer provided complete and continuous coverage of the spectral region from 200 to 650 nm and allowed spectral lines to be identified with an accuracy of 1–2 pm.

Howard Malmstadt was a true giant of Analytical Chemistry and clearly one of the most influential analytical chemists of the last 50 years. Howard, through his own work and that of his students (first generation) and their students (second generation) and their students' students (third generation) changed the course of Analytical Chemistry. His research interests were broad and ranged from analytical solution chemistry (titrimetry and reaction rates) and electrochemistry to atomic and molecular spectroscopy, chemical instrumentation, clinical chemistry and automation. Howard was also one of the most innovative and influential educators of our time. He changed forever the analytical curriculum through his many books on Electronics for Scientists , most written in conjunction with Chris Enke and Stan Crouch. Their texts and short courses went from pioneering the application of tube-based analog electronics (servo systems and operational amplifiers) in scientific measurements to the impact that integrated circuits and digital electronics would have on laboratory measurements. He strongly believed in the importance of “hands-on” in education. To this end, he expended considerable personal effort and time to see not only the development and commercialization of an effective laboratory infrastructure to support education in analog and digital electronics, but also oversaw the development of modular instrumentation for spectroscopy. Over the years he received many awards from the Analytical Chemistry community for his outstanding efforts and contributions to teaching and research. Many of Howard's students went on into academia. They and their students now represent the ongoing legacy for analytical chemistry that evolved from Howard's laboratory at Illinois. A remarkable diversity of research programs are underway in their laboratories. Topics range from atomic, laser, mass, and Raman spectroscopy to detection technology, analytical education, micro-fabricated instrumentation, and intercellular analytical measurements.

Detailed spectra highlighting the neutral atom emission characteristics (i.e. I lines) for Cu, Zn, Ag and Cd in a glow discharge device are presented in this study. A particular focus is the presentation of spectra that document the many high excitation energy neutral atom lines that are observed in these spectra. For Cu, several spectral lines originating from levels close to the ionization potential of copper are observed including lines from the so-called autoionizing levels which are actually just above the ionization potential for copper. Generally similar results are seen for Ag, Zn and Cd, including the observation of many high excitation energy neutral atom lines of Zn originating from the upper levels on the triplet side of the energy level diagram. The spectral data point to ion–electron recombination processes followed by stepwise de-excitation and radiative decay as a key mechanism in setting the spectral character of neutral atom emission in a glow discharge device. Unambiguous identification of spectral lines for specific transitions was facilitated by the acquisition of all spectral data utilizing a UV–visible Fourier transform spectrometer. This spectrometer provided complete and continuous coverage of the spectral region from 200 to 650 nm and allowed spectral lines to be identified with an accuracy of 1–2 pm.

A quantitative study of the determination of halides and halogenic anions by negative ion electrospray mass spectrometry (ES-MS) is presented. Calibration plots were found to be linear over a range of 2.5–4 orders of magnitude for F - , Cl - , ClO 3 - , ClO 4 - , Br - , I - and IO 3 - when a 1.0×10 - 4 mol l -1 level of external electrolyte was added to the standard solutions. Detection limits ranged from 0.5 ng ml -1 for the perchlorate ion up to a blank limited 35 ng ml -1 for chloride. An attempt was also made to determine the level of fluoride present in mouthwash samples. Measurement of the fluoride content utilizing a calibration curve produced excellent agreement with results obtained by measurement with a fluoride ISE for two synthetic mouthwash samples but poor agreement for two commercial samples. However, excellent agreement between the two methods was obtained for the commercial samples using the method of standard additions with ES-MS.

An electronic spectrometer based on an acousto-optic tunable filter (AOTF) is presented. These devices are electronically tunable, narrow-band light filters with no moving parts. The wavelength range from 350 to 600 nm can be covered with a single device, the entire spectrum is scanned in less than 1 s, and any wavelength can be randomly accessed in 0.1 ms. The resolution [full width at half-height (FWHH)] was determined to be 0.22 nm at 361 nm, and the standard deviation of peak position was usually less than 0.03 nm. Under software control, the AOTF can be stationary on a line, peak-hop between any 20 different lines, hop between 20 regions of any size, scan a spectrum, or operate as a wavelength modulation spectrometer. Operation of the spectrometer is illustrated by using hollow cathode and inductively coupled plasma atomic emission sources.

In this report an in situ laser ablation system for inductively coupled plasma-atomic emission spectrometry (ICP-AES) is described that eliminates the aerosol transport step associated with conventional laser ablation sample introduction systems. The concept of this system is to place the sample inside the ICP torch immediately below the plasma discharge. This can be accomplished using a direct sample insertion system. The laser is then focused on the sample by a lens placed above the plasma and ablated material is directly injected into the plasma. For ablation with a Q-switched Nd-YAG laser (single pulse) this results in an emission signal that has a duration of about 0.7 ms, in contrast to a conventional ablation system where signal durations are measured in seconds. This translates to a dramatic improvement in sensitivity for the in situ system over a conventional system. Measurement considerations are discussed, results are presented for the analysis of Al and steel samples, and the in situ system is briefly compared with a conventional laser ablation system.

A parametric investigation of an electrospray ion source and interface has been carried out with a focus on elemental analysis. The source and interface variables investigated were the curtain-gas flow rate and the voltage biases of the electrospray capillary tip, the front plate, the sampling plate, the skimmer, and the barrel ion extractor lens. The analytes studied (M+ and M++) included the alkali metals, the alkaline earth metals, and cobalt—all prepared in methanol (MeOH) solutions. The two most important interface parameters in terms of their effect on the nature of the resulting mass spectrum were the curtain-gas flow rate and the sampling-plate voltage bias. A minimum, but modest, flow rate of curtain gas was required in order to observe analyte ion signals, and, when combined with a low sampling-plate voltage, the observed signal species were primarily analyte ion–solvent clusters [M(MeOH) n+1 and M(MeOH) m+2]. As the values of these two parameters were increased, these species were declustered, plus-two analyte ions were reduced to plus-one species, and ultimately the mass spectra were dominated by the bare singly charged analyte ion (M+). Also, these two variables (curtain-gas flow rate and sampling-plate voltage) seem to act in a synergistic manner, with neither variable alone able to effect complete declustering and charge reduction.

The electrospray mass spectra of several elements in the lanthanide series are presented with the focus being on understanding the basic processes that occur to yield such spectra. The solution chemistry and the physical properties of the elements have a profound effect on the type of species observed in a mass spectrum. To perform elemental analysis by electrospray mass spectrometry, harsh declustering conditions are typically used. This results in a spectrum consisting of the bare metal ion (Ln[sup +] or Ln[sup 2+]) and molecular ions (LnO[sup +]) such as oxides as well as contributions due to matrix ions. The sampling conditions required to obtain such spectra require a large potential difference between the sampling plate and the skimmer at the atmosphere to vacuum interface, resulting in efficient collision-induced dissociation conditions. To monitor the process, a frame by frame illustration is used where the potential difference between the sampling plate and skimmer is increased in increments and the resultant spectra are captured. With this procedure, the dominant processes may be highlighted and explained step by step and a clearer understanding of the processes involved is obtained. 43 refs., 7 refs., 1 tab.

Electrospray mass spectrometry (ES-MS) is shown to be suited for the direct determination of ionic species in solution. Examples used in this investigation of ES-MS for elemental speciation determinations included several inorganic ionic species of chlorine, iodine, sulfur, and iron. These species were differentiated on the basis of differences in the molecular form and/or the oxidation state of the analyte ion. The inorganic complexes of silver-cyanide and iron-fluoride were also measured in this assessment. Finally it is shown that ES-MS is applicable to the determination of organometallic compounds. While ES-MS is not an ideal speciation technique, there is considerable evidence to indicate that ES-MS can become an invaluable tool with which species distributions in a wide range of sample types may be probed.

A hollow cathode discharge capable of continuous operation with solution sample introduction is described. Discharge current densities up to 0.64 A cm 2 are maintained in a helium plasma. Analyte emission intensities are optimized in terms of anode placement in relation to the hollow cathode, carrier gas flow rate, discharge current and sample solution flow rate. Detection limits for selected elements are reported and range from 0.03 ng ml for Li to 200 ng ml for Zn. Temporal stability of the discharge is examined and a calibration curve for Li is presented.

The quantitative aspects of elemental electrospray mass spectrometry are investigated with particular emphasis on the factors affecting the ability to establish linear calibration curves. It is shown that linear calibration curves can be obtained for trace elements if the analyte signal is ratioed to the signal from a constant amount of a similarly charged electrolyte species. Linear calibration curves can be established over a concentration dynamic range of at least four orders of magnitude. The added component seems to function as a stabilizer and monitor of the electrospray process and as an internal standard. In certain cases, species generated by acidification of the solvent may be used as electrospray stabilizers.

Spectral results are presented illustrating the capability of electrospray mass spectrometry (ES-MS) for the determination of the composition of solution samples. The solution components that can be determined include the elemental and molecular forms of anions and cations. Three modes of positive-ion ES-MS are described: the ion cluster mode, the metal-ion mode, and an intermediate mode. The modes are established by operating the electrospray source at specific voltages and curtain gas flow rate values, and each mode provides a unique mass spectral picture of the solution components with primary focus on cationic species (i.e., metal ions). Results are also presented for operation of the electrospray source in negative-ion mode. In this mode both elemental anions (i.e., halides) and molecular anions (i.e., oxo-anions) can be determined.

Economic development is the most important agenda in the international trading system today, as demonstrated by the Doha Development Agenda (DDA) adopted in the current multilateral trade negotiations of the World Trade Organization (the Doha Round). This book provides a relevant discussion of major international trade law issues from the perspective of development in the following areas: general issues on international trade law and economic development; and specific law and development issues in World Trade Organization, Free Trade Agreement and regional initiatives. This book offers an unparalleled breadth of coverage on the topic and diversity of authorship, as seventeen leading scholars contribute chapters from nine major developed and developing countries, including the United States, Canada, Japan, China (including Hong Kong), South Korea, Australia, Singapore and Israel.

A graphically-oriented data base of spectral interferences dut occur in inductively coupled plasma-mais spectrometry and glow discharge-mass spectrometry has been developed. The program is called “MS Interview” and runs on a Macintosh computer. The program allows one to specify which technique (ICP or GD) the various interferences will be presented for, and for the case of the ICP, the acid matrix background. Bated on these parameters the program provides a listing of interferences broken down into the following categories: Isobarics, Oxides, Doubly Charged Species, Background Dependent, and Matrix Dependent. For the glow discharge case there are two additional categories: Argides and Dimers. Interference information is provided for all masses of all elements and is easily accessed via mouse operations from a periodic table window and element mass spectral windows. The program is expandable to include other ion sources and interferences can be added or deleted as required by the user. Finally, the program also includes a small library of typical background spectra that can be displayed and manipulated. This article is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta B (SAB). The hardcopy text is accompanied by a disk containing the program MS Interview, a manual, a reference list, and a bar graph format mass spectral library of the elements.

Preliminary results for the analytical use of electrospray mass spectrometry (ES-MS) for elemental analysis are presented. Spectra with the declustered plus-one ion (M+) as the dominant species have been measured for the alkali metals (Li, Na, K, Rb, and Cs) and for several transition metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, and Cd) in both aqueous and methanol solvents. A number of background ions are also observed including MH+, MO+, MOH+, and MOH(H2O)+. For vanadyl sulfate and uranyl nitrate, ES conditions can be adjusted to produce VO+ and UO2+ as the dominant ions in the mass spectra, indicating that direct speciation of inorganic solution components is possible. On the basis of these preliminary results, it appears that electrospray may offer a low-cost and simple generic ion source for elemental mass spectrometry.

An interferometer system has been designed and built specifically for the implementation of Fourier transform spectroscopy in the ultraviolet and visible spectral regions. The moving mirror is attached to a rectangular air-bearing/permanent magnet assembly. Fixed, twin coils provide the force by which the mirror is translated. A unique two-channel zero-force servo system has been developed to maintain a constant mirror velocity on both the forward and backward strokes of the moving mirror. The travel of the moving mirror is automatically controlled to be symmetrically centered about the position of zero path difference. The drive length is precisely presettable and is controlled utilizing an absolute reference laser fringe counting system. The maximum travel is 1.04 cm on either side of the position of zero path difference. A full stroke drive is equivalent to 65,536 cycles of the 1 HeNe reference laser-fringe ugnai and one stroke takes 6.5 s. The mirror automatically cycles back and forth enabling the signal averaging of repetitively generated inlerferograms. Oe-aliased spectra can be measured using a frequency multiplied version of the reference laser fringe. A phase-locked loop-circuit provides data acquisition clocking signals with rates of four times and eight times that of the basic laser-fringe signal. All data acquisition and processing is carried out using a Macintosh II computer.

The qualitative spectral performance of a Fourier transform spectrometer developed primarily for atomic emission spectrochemical measurements is discussed and presented. The system is capable of measurements in the ultraviolet, visible and near-infrared spectral regions. In the ultraviolet region the spectrometer has an absolute wavelength accuracy of 1 pm and a wavelength precision approaching 0.1 pm. Resolution and line shape considerations are presented in detail The demonstrated spectral bandwidth is 0.63 cm −1 which corresponds to 2.5 pm at 200 nm and 5.7 pm at 350 nm. The aliasing aspects of FTS in the ultraviolet and visible spectral region are presented and the ability to de-alias a spectrum in order to have an unambiguous spectral axis is illustrated. The potential existence of spurious spectral lines in FTS is also briefly considered. This article is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta B (SAB) and several original data sets are provided on computer disks accompanying this publication. With the use of a program called SpectroPlot, also included on the disks, a first-hand assessment of the data acquired by the FTS is possible. The program SpectroPlot is the subject of a separate publication also presented in Spectrochimica Acta Electronica .

A powerful graphically-based software shell for processing, displaying and manipulating interferometric and spectral data is described. This program (SpectroPlot) wad developed to support an ultraviolet-visible Fourier transform spectrometer and tuns on Macintosh computen. It allows men to handle multiple data sets in independent windowi and permits extensive direct user interaction with the data through an advanced user interface. In the first instance, a wide range of data viewing options (i.e zoom and selection operations) are available for data display and study. Also with the program the user can implement a wide range of mathematical operations and statistical calculations on individual data sets and between multiple data sets. The mathematical operations range from basic arithmetical calculations (addition, subtraction, multiplication, division, integration, and differentiation) to more complex procedures such as fast Fourier transforms, digital filtering, spectral interpolation, peak searching, and apodization. Finally, a range of options is provided for the transfer of data sets to and from external application programs. Although developed for a Fourier transform spectrometer, SpectroPlot is a powerful and generic program for the graphical manipulation and analysis of spectrochemical data for Macintosh computers. This article is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta B (SAB). The hardcopy text is accompanied by disks containing the program SpectroPlot, some useful external routines, sample data sets, and a manual.

Spectral-interference problems in inductively coupled plasma-mass spectrometry (ICP-MS) can be recognized by making analytical determinations at more than one mass for elements that have more than one naturally occurring isotope. If the results for the isotopes do not agree, then a spectral-interference problem is often indicated. A powerful tool that can be used to pinpoint the source of spectral interference is to compare results (even for mono-isotopic elements) and result discrepancies, sample-by-sample, with the sample composition of the suspected sources of the spectral interferent. This can be effectively carried out with the use of computer-generated bar graphs. The major elements in a sample are frequently the source of species that cause spectral-interference problems. The concentrations of the major elements in a sample may, in some cases, be more readily determined by ICP-atomic emission spectrometry (ICP-AES). When ICP-AES results for major components in a set of samples are compared to ICP-MS results of the minor components in the same set of samples, spectral interferences may be revealed. The application of this approach to the identification of spectral interferences is illustrated for the determination of Ba, Zn, Cu, and Ni in a set of ground-water samples.

Two types of low cost glow discharge (GD)ion source have been designed and contracted that can be interfaced to the mass spectrometer of an inductively coupled plasma-mass spectrometry (ICP-MS) system. In one system the cathode (sample) is a central pin and in the second system the cathode (sample) is a disk. This second system is based on the “Grimm” design with a floating restrictor. Either system can be bolted onto the interface system of a SCIEX/Perkin-Elmer ELAN Model 250 or 500 ICP-MS in place of the normal sampling cone. Successful operation requires that the anode of the GD source be biased slightly positive and the shadow stop of the ELAN slightly negative with respect to the grounded slammer and interface plate. The application of these GD ion sources to the qualitative and quantitative analysis of low alloy steel, stainless steel and brass samples is illustrated. In particular, complexity of GD-MS spectra are assessed with respect to argide and dimer levels. In general the spectra are quite simple with argide levels in the 0.1% to 0.01% range and dimers generally less than 0.01 to 0.001%

An optical emission spectrometer has been added to an inductively coupled plasma-mass spectrometer. This system allows the simultaneous observation of emission and mass spectrometric signals from an inductively coupled plasma. Because of the difficulty in mounting the emission spectrometer near the plasma of the mass spectrometer a fiber optic cable was used to couple the optical spectrometer to the mass spectrometer plasma. In this study, the operating conditions that provide peak signal responses for atomic emission and mass spectrometric signals are compared and contrasted. The signals are measured for a range of operating conditions and it is shown that optimal conditions must be compromised when the signals are simultaneously observed. In addition to analyte ions, the emission and mass spectrometric signals of analyte oxide species have also been simultaneously observed and matrix effects in inductively coupled plasma-mass spectrometry and atomic emission spectrometry are directly compared.

A number of data processing and data acquisition methods are presented that enhance the performance of a photodiode array (PDA) spectrometer. Zero-filling or Fourier-domain interpolation is used to interpolate peak shapes. This improves the accuracy and precision of spectral peak height and position measurements and can be used to overcome spectral line/diode registry effects. A procedure is presented for the automated calibration and recalibration of the wavelength window measured with a photodiode array spectrometer. This method is based, in part, on cross-correlation of spectral patterns. Finally it is shown that by programming of the integration time, several spectra can be combined into a single wide-dynamic-range spectrum. Taken as a whole, these data processing and acquisition techniques improve the accuracy, precision, and dynamic range of spectrochemical data acquired with a PDA spectrometer. This is illustrated by using the system for the rapid measurement of excitation temperatures of plasma sources.

The analysis of the rare earth elements by inductively coupled plasmamass spectrometry is complicated by spectral overlap problems involving M+, MO*, and MOH+ ions. Two correction schemes are compared in this study. One correction scheme is the classical algebraic approach (Gauss elimination) and the other is a method based on principal components analysis, also known as factor analysis. Both schemes work well, but the principal components analysis approach is considerably more flexible, is easier to expand to more elements, and can tolerate missing data.

Direct sample insertion (DSI) is a particularly attractive method for sample introduction for inductively coupled plasma-atomic emission spectrometry (ICP-AES). In this approach a sample is placed into or onto a probe with subsequent introduction of the sample carrying probe, via the central tube of the torch, into the plasma. An extensive review of DSI devices for the ICP has been presented by Karanassios and Horlick.

An automated direct sample insertion device for inductively coupled plasma-atomic emission spectrometry is described. Graphite cup sample probes can be mechanically inserted into the plasma, and the insertion sequence is completely under computer control via a stepper motor. Multichannel high-speed electronics have been developed for a direct-reading polychromator that allow the real-time digitization of the transient spectral signals from up to six channels simultaneously. A small robot arm is used to automate exchange of the graphite cup sample probes. Custom software has been developed for system control and signal processing. For volatile elements such as Zn and Cd, detection limits are in the pg range for a 10 μL solution sample.

A computer controlled direct sample insertion device for inductively coupled plasma-atomic emission spectrometry is described. Sample carrying probes based on graphite cups, metal cups or wire-loops can be pneumatically inserted into the plasma from a carousel capable of holding up to 24 probe assemblies. The transient spectral signal resulting from this sample introduction system is measured using a direct reading polychromator. A measurement system is described that is capable of digitizing, in real time, the complete transient spectral signal simultaneously from four channels of the direct reader. An extensive software package has been developed to support the direct sample insertion system. It contains subroutines for automation, control, fault-diagnosis, data acquisition and peak-type signal processing. The software is window-based and has extensive graphics display, graphics processing and data and information management capabilities.

The effects of adding N 2 to the outer gas flow of an Ar plasma in inductively coupled plasma mass spectrometry (ICP-MS) are illustrated. With 5% N 2 added to the outer gas flow and provided the central (nebulizer) gas flow is increased, modest signal enhancements (up to a factor of 4) are observed. The degree of enhancement depends on the extent to which an element forms a strong metal oxide bond and also, to some extent, on ionization potential. An important feature of N 2 mixed gas plasmas for ICP-MS is that the signals for analyte oxide species (MO + ) and certain background species (ArO + , ArOH + , Ar 2 + , ClO + , and ArCl + ) are significantly reduced (an order of magnitude) by the addition of N 2 to the outer gas flow. In addition to these observations, some results are also presented for O 2 and air (outer gas) mixed gas plasmas and N 2 (central gas) mixed gas plasmas.

A direct sample insertion device allows insertion of sample carrying probes into an inductively coupled plasma discharge. In this study, analyte emission temporal behavior for such a device was surveyed for several elements with a range of vaporization properties. The emission time behavior for most elements was characterized as a function of probe geometry, composition, insertion speed and insertion position as well as applied plasma power. A long undercut graphite electrode was found to be the best shape for all probe geometries tested. Furthermore, it was demonstrated that the sample carrying probe should be inserted rapidly to a position corresponding to the top of the load coil and the plasma power should be high (1.75–2.00 kW) in order to attain best analytical performance.

A commercial program (MacSimion) has been used to model the einzel lens and bessel box input lens system of an inductively coupled plasma-mass spectrometer (ICP-MS). A number of plots are presented illustrating the effect of various lens voltages on ion trajectories. The trajectories are dependent on ion kinetic energy and since ion kinetic energy is mass dependent in ICP-MS, these plots clarify the mass dependence of ion lens voltage settings. Plots are also presented illustrating the interdependence of some lens voltage settings and how, in fact, different lens voltage settings can result in similar ion throughput. The model can be used to predict relative signal intensities for a range of ion masses as a function of lens potentials and these are shown to agree with experimentally measured data.

The size of the orifice in the sampling cone of the interface in an inductively coupled plasma-mass spectrometer (ICP-MS) has a major impact on signal characteristics. In particular, for oxide forming elements, the MO+/M+ ratio is very dependent on orifice size. This is illustrated for a range of elements (La, Ho and Yb) as a function of nebulizer gas flow and for sampling cone orifice sizes ranging from 0.51 to 0.94 mm. In addition the size of the sampling orifice changes the shape of the signal vs nebulizer flow rate plot and this is illustrated. A curious and important observation is that the signal dependence on nebulizer flow rate is essentially identical for all analytes at any one orifice size if the analyte and analyte oxide (when observed) responses are summed. This indicates that the sampling orifice is the primary location of oxide formation in ICP-MS. Finally the effect of the skimmer orifice diameter on analyte signals is also illustrated for orifice diameters of 0.76, 0.89 and 1.0 mm in conjunction with sampling orifice sizes ranging from 0.51 to 0.94 mm.

The effects of varying the sampler-skimmer spacing in an inductively coupled plasma-mass spectrometer are illustrated. The signals for a number of species were monitored including background ions (ArN+, ArO+, ArOH+, Ar2+, Ar2H+), background continuum, analyte ions (Cu+, Ce+, La+), analyte oxide ions (CeO+, LaO+), and matrix induced ions (ArNa+). As the sampler-skimmer spacing is increased over that normally used, the signal for some species decreases in intensity while the signal for others increases in intensity. There is a wide range of differential behavior and in some cases the signal changes are quite dramatic. In addition to presenting results for an Ar plasma, measurements are also presented for a N2-Ar mixed gas plasma. For some species, the signal changes observed when the sampler-skimmer spacing is increased are quite different with the N2-Ar mixed gas plasma than with the Ar plasma and are, in some cases, opposite to signal changes observed with the Ar plasma. It appears that a larger sampler-skimmer spacing is more appropriate for a N2 mixed gas plasma than the spacing normally used for a pure Ar plasma. Finally the effect of sampler-skimmer spacing on matrix effects is presented and it appears that matrix effects are not induced in the zone between the sampler and the skimmer.

With a graphite cup based direct sample insertion device poor results are obtained for refractory and carbide forming elements, such as Al, B, Ca, Sr and Zr. In this work, several chemical modification reagents have been tested in order to improve the vaporization characteristics of such analytes. Reagents tested include KCl, KF, NaCI and NaF. The best overall results were obtained using NaF added as a 10 μl spike of 0.25 M NaF to the sample carrying cup. With this treatment the above analytes can be quantitatively determined. The direct determination of B in powdered CaSO4 is shown as an example of NaF chemical modification.

Electrospray ionisation (ESI) was used to generate gas-phase anions that were subsequently separated by high-field asymmetric waveform ion mobility spectrometry (FAIMS) and detected by quadrupole mass spectrometry (MS). ESI-FAIMS-MS provided selective and sensitive determination of perchlorate at low nanomolar levels, relatively free from the interferences commonly observed for this analysis using conventional ESI-MS. In particular, the gas-phase separation of ions in FAIMS eliminated isobaric overlaps of bisulfate and dihydrogen phosphate with perchlorate. Using the FAIMS interface, analysis of 1 µM perchlorate in a 10 µM sulfate solution yielded a signal-to-background ratio (S/B) improvement of over four orders of magnitude (at m/z −99) compared with ESI-MS. The detection limit for perchlorate (in 9∶1 methanol–water with 0.2 mM ammonium acetate and 10 µM sulfate) was 1 nM (≈0.1 ppb).

Publisher Summary The most successful and widely used source for elemental mass spectrometry is the inductively coupled plasma (ICP). Reasons for its unrivaled success arise primarily from the fact that it is capable of efficiently converting almost any sample into gas phase molecular, atomic, and ionic vapor with little or no sample pretreatment. The ICP is also very efficient in its destruction of chemical information about the nature of an element in a sample that mass spectrometry is capable of determining, specifically its molecular form and charge state. There are two general approaches to elemental speciation: (1) integration of separation technology with element specific detection and (2) development and application of soft ionization sources. Electrospray ionization mass spectrometry (ESI-MS) has become a widely used technique in biological, pharmaceutical, and medical research. Its ability to transfer macromolecules in high yield from solution to gas phase without degradation has revolutionized the study and detection of various analytes. In addition to offering a means for routine organic analysis, the gentle nature of the ESI interface also provides a mechanism to probe non-covalent interactions and binding of drugs and carcinogens to target peptides, proteins, and deoxyribonucleic acids (DNA).

A software platform for computer-based education in Fourier transform spectroscopyGreg Fulton and Gary HorlickDepartment of Chemistry, University of AlbertaEdmonton, AlbertaCanada T6G-2G2ABSTRACTThe program SpectroPlot1 was developed in this lab to provide a window based program for acquiring, processingand displaying UV-VIS interferometric data. This program also provides an excellent platform for teaching students basicFourier transform concepts through the use of an extensive library of interferograms and spectra. This allows a student toperform required manipulations on data and to see the results first hand. As well this allows the flexibility of studentinitiated experimentation with different processing techniques (without additional laboratory cost) to observe the effects ofproper and improper data collection and processing. The program and spectral library are available from the authors for theMacintosh. PC users may acquire a text version of the spectral library.1. ThE COMPUTER PLATFORM SPECTROPLOTSpectroPlot is a graphically based computer program for the Macintosh. It was created in this lab for acquiring,processing, and displaying data from a compact UV-VIS-FTS fabricated in this lab at the same time. Since its creationhowever the program has also found use in the acquisition and processing of data from PMTs, PDAs, acquiring electricalsignals for diagnostic purposes, and for use as a data collector in the electronics teaching lab in the Chemistry department.Its wide utility is based on its simple graphical interaction with acquired data. and the wide range of spectral manipulationsavailable to process data. On the computer system it is presently employed (Macintosh IIfx, 16 MB RAM) up to 30windows of data may be viewed simultaneously. Data sets of up to 256k pts have been transformed. The spectralmanipulations available to the user include: addition, subtraction, multiplication, division (scalar or vector (e.g. add twospectra)), integration, differentiation, digital filtering (low pass, high pass, band pass, notch), custom X axis calibration(including nm and statistical calculation, smoothing, FFF (real, complex or amplitude), zero filling (spectra orinterferograms), truncation of data in powers of two, gaussian apodization, graphical alias management, and many others.

Summary In a recent publication [1] we described a computer program called “MS InterView”. This program is a graphically-oriented data base intended to provide ICP and glow discharge mass spectroscopists with the ability to display, access, and manage elemental mass spectrometry spectral interference data. The program was written for the Apple Macintosh. We have had a number of inquiries as to whether DOS or Windows compatible versions of the program could be made available. To this end, we have written a Microsoft Windows version of the program. For a discussion of the capabilites of the program, we refer the reader to the original article [1] and the accompanying documents in electronic form. The purpose of this short note is simply to make this new version of the program available to the readers of SAE. This article is an electronic publication in Spectrochimica Acta B (SAB). The hardcopy text is accompanied by a disk containing the program MS InterView for Windows, a Windows version of the manual, a reference list, and a bar graph format mass spectral library of the elements.