SAS-CHICAGO

Reliability, robustness, and the ability to generate easily understood data are desirable characteristics atomic spectrometry possesses. In terms of scientific instrumentation, these techniques are quite mature. Nevertheless, they account for a large fraction of the chemical analyses done in today’s laboratories.

Atomic spectrometric techniques have undergone some fascinating improvements in recent years. Many of the improvements are a function of improved atom/ion reservoirs, sample introduction approaches, primary sources, and photon (or ion) optics.Improvements in atom/ion reservoirs and sample introduction have led to more sensitive and stable detection.

Currently, many new forms of atomic spectrometry are being developed in order to meet the demand for new methods of chemical analysis. Many of the forms of atomic spectrometry being developed contain different types of atom/ion reservoirs and sample introduction methods to solve problems that some more developed instrumentation may be unable to solve, such as surface/depth analysis or more sensitive and selective detection of specific elements. Although some of these forms of atomic spectroscopy are relatively new, many of them have led to some promising improvements for specific applications.

In this talk, an overview of atomic spectrometric techniques, including electrothermal, flame, plasma, arc, and glow discharge methods will be presented.

Metals Digestions Made Easy

Les Orr, Environmental Express, Inc.

For the past four decades or so, significant progress has been made with instrumentation for the determination of metals. But the digestion procedure for dissolution has remained relatively the same. As MDL’s decreased, labs experienced contamination on a scale that previously went undetected.

Technology has finally caught up to the prep lab, incorporating equipment that benefits the digestion procedure by eliminating many of the chances for contamination. Corrosion-free materials and disposable “glassware” is only the start of the benefits.

As a natural progression, automation has occurred thus reducing safety, labor and more QC concerns for the lab. Now the instruments for detection are capable of reaching the levels intended for “real world” samples.

A “How-To” Practical Approach to Microwave Digestion

Elaine Hasty, CEM Corporation

This presentation will focus on the practical aspects of pressurized digestion and dissolution for organic and inorganic sample types. Included will be an overview of reagent choices and temperature programs appropriate for various sample matrices. The various approaches to control – temperature, pressure, single reference vessel or all vessel control will be outlined along with their pros and cons.

A straightforward approach to method development for unknown samples will be presented with clear and concise guidelines given for various types of samples.

Better, Faster, Stable-er Standards Preparation

Thomas Rettberg, Ph.D.

VHG labs

276 Abby Rd

Manchester, NH 03103

Advancements in technology have not reduced the fundamental basis of most instrumental techniques--the need for a current calibration created using calibration standards. Optical and mass spectrometric techniques for “metal group” determinations have developed over time to be increasingly multi-element, commonly at lower concentrations, more likely to include non-metals or problematic elements; such as mercury, and tend to involve more direct analysis of complex matrices. One aim of this talk will be to cover some of the interdependencies associated with preparing appropriate and stable calibration standards for these situations.

Increased throughput is also a key objective of most laboratories. It is important to understand that the solution matrix (whether aqueous and organic) for blanks and standards be well-suited for shortened uptake and rinse times coupled with long sample batch duration. General guidelines for determining the best stock standard to use, the meaning of traceability, and expiration of certification will also be discussed.

The Role of the Nebulizer in ICP Sample Introduction

Dr. Geoff Coleman, Meinhard Glass Products

The role of the nebulizer is to convert an ostensibly homogeneous sample solution to an aerosol for efficient and reproducible transport to the plasma where it will be rapidly and reproducibly desolvated, vaporized, dissociated, then excited and/or ionized. Each of those processes has an impact on its successor. If the processes are not highly reproducible in time, space and completeness, the analytical signal cannot be reproducible either. Since the rate of evaporation of solvent from a droplet is a function of the surface area to volume ratio, the smaller the droplet, the faster and more completely it will desolvate then vaporize, dissociate, and undergo excitation and/or ionization. Studies show that little signal is derived from droplets larger than 5 um; most comes from droplets that are 3 um or less, in diameter. Unfortunately, the nebulizers which produce the smallest droplet sizes are limited in their applicability for other reasons.

The fact is, no nebulizer does everything well; each has its strengths and weaknesses; each is better suited to particular set of circumstances whether it is a matter of cost, convenience, robustness, ease of use, stability, reproducibility, the size of the aerosol it produces, as well as other criteria that might apply. We will briefly look at how nebulizers work, what is available, some strengths and weaknesses of each design, and where each is most useful.

Laser Ablation Fundamentals, Techniques and Applications

Mike Colucci, New Wave Research

Laser ablation ICP-AES and ICP-MS has been a rapidly evolving analytical tool since the early 1980’s. The fundamental 1064nm wavelength of a Nd-YAG laser is stepped down by harmonic generation to produce 266nm, 213nm and 193nm wavelengths suitable for ablation of solid materials and introduction of the generated aerosol into an ICP source for trace element and isotope analysis. Transmissive materials, such as high purity quartz and fused silica, require deep UV wavelengths (213-193nm) for effective coupling, whereas opaque materials such as metals and plastics ablate efficiently at the 266nm wavelength.

The laser ablation systems are equipped with a beam delivery system that enables the laser to be focused upon a sample surface at a range of spot sizes at the micron scale. Laser ablation is an attractive alternative to solution analysis due to 1) virtually no sample preparation, 2) high spatial resolution, 3) high transport efficiency, and 4) it is a microdestructive technique. Application areas currently utilizing laser ablation include, but are not limited to: Geological Sciences, Forensic Sciences, Life Sciences, etc. Product lines span the UV spectrum from 266nm to 193nm laser ablation systems. Software and hardware capabilities allow complete automation for a range of experiment types.

Temperature Controlled Spray Chambers and Specialty Torches

Jerry Dulude, Glass Expansion, Inc., Pocasset, MA

Typically, the only time an ICP analyst is concerned with spray chamber temperature is for the analysis of volatile organic solvents that require a chilled chamber to maintain the plasma. Otherwise, it is assumed that 1) room temperature is ideal for all aqueous applications, 2) the spray chamber is at room temperature, and 3) room temperature is constant. All of these assumptions will be refuted in this paper. It will be demonstrated that spray chamber temperature is as critical a parameter as nebulizer gas flow or RF power and can be appropriately adjusted to optimize an ICP method. The effects of spray chamber temperature will be examined with respect to intensity, detection limits, plasma robustness, and the degree of suppression.

The standard (i.e. that which is shipped with the instrument) ICP torch is assumed to be ideal for all applications. In reality, specialized torches provide superior performance for specific applications. Specialized torches are available and will be described for applications such as the analysis of brines, engine oils, and semi-conductor solvents.

Specialized Introduction Techniques for Liquid and Solid Samples

Using ICP-AES and ICP-MS Detection

Dr. Fred Smith, CETAC Technologies, 14306 Industrial Road, Omaha, NE 68144.

This presentation is comprised of two parts, with the first concerning liquid sample introduction and the second direct solid sampling with little or no sample preparation.

Specialized liquid sample introduction techniques for ICP-AES and ICP-MS may be used for a number of reasons. These reasons can include enhanced analyte signal, reduction of sample matrix interferences, the introduction of very low volume (< 1mL) samples, and shorter analysis times. A variety of techniques will be described, including ultrasonic nebulization, membrane desolvation, inert low-flow nebulizers, hydride generation, and discrete sampling.

Direct solid sampling can avoid a number of problems with acid digestion of a solid: difficulty of digesting certain solids (ex. ceramics, polymers), contamination from impurities in mineral acids, and loss of element distribution information. The technique of laser ablation will be described, with details of typical laser wavelengths, applications, and methods of calibration.

Thursday, May 8, 2008 at The McCrone Group 850 Pasquinelli Drive,Westmont, Illinois 60559 630-887-7100

Thursday, May 8, 2008 at The McCrone Group
850 Pasquinelli Drive,Westmont, Illinois 60559 630-887-7100