The top-of-line SPECTRO ARCOS ICP-OES analyzer evolves elemental analysis to the next level

The worldwide chlor-alkali industry produces around 60 million metric tonnes of chlorine annually. Nearly all industrial chlorine production is by the electrolysis of brine (sodium chloride solution). Both chlorine and sodium hydroxide, the other product of this process, are basic raw materials for the chemical industry and as such world demand follows worldwide economic trends, and is particularly strong in the developing economies of Asia. Traditionally, the brine electrolysis was carried out in cells using liquid mercury as the cathode. This process has the potential for loss of mercury into the environment and into the product. Environmental concerns have led to a steady decline in chlorine production by this method, which is being superseded by the mercuryfree ”membrane process”. The efficiency of the membrane process can be impaired by the presence of trace impurities in the brine. To control the quality of the brine, it is necessary to measure these impurities at the parts-per-billion level. This can be done using Inductively Coupled Plasma–Optical Emission Spectroscopy (ICP-OES). For successful and efficient analysis however, the instrument chosen should be capable not only of achieving the necessary detection limits, but also of operating continuously with samples that contain NaCl concentrations approaching 25-26 %, and preferably without dilution. This paper illustrates how the design and performance of the SPECTRO ARCOS ICP-OES make it the instrument of choice for this demanding application. 

Scientific evidence plays a vital role in today’s justice system: many high profile criminal investigations reach their conclusions almost entirely on this evidence. Many branches of science are employed in accumulating forensic evidence, from highly publicized techniques like DNA profiling to pathology, botany and of course chemical analysis. Elemental analysis of an object found in the course of an investigation can yield valuable clues to its origin and history. The object itself may, however, need to be presented as evidence, so any technique used for this analysis should ideally be non-destructive. Variation in sample type and size may be almost infinite: from a soil sample to a bullet to a microscopic speck of gunshot residue or fragment of glass. Archaeometry, the application of scientific methods to archaeology, has very similar requirements. Energy Dispersive X-ray Fluorescence (EDXRF) spectrometry is a versatile analytical technique that can satisfy both of these needs: it is non-destructive, requires very little sample preparation and can be configured to handle any sample size from a large surface to a few microns. The wide range of EDXRF spectrometers from SPECTRO Analytical Instruments and EDAX, member companies of AMETEK Inc.‘s Materials Analysis Division, provide solutions to many elemental analysis tasks in forensic investigation and archaeometry. 

One unfortunate legacy of man’s activity is contamination of the environment. Soil, water and air can all be polluted by harmful substances, and this contamination can be directly toxic or can pass into food or other products for human consumption. Controlling harmful emissions from industry and the safe and environmentally responsible disposal of waste are major issues for governments and industries worldwide.

The analysis of environmental samples is an essential part of detecting and controlling pollution. Certain elements, particularly the “heavy metals” like lead, cadmium and mercury are notorious for their toxicity, and usually need to be measured in the parts-per-million concentration range. The most popular and convenient analytical technique for environmental screening for these elements is Energy Dispersive X-ray Fluorescence (EDXRF). Screening waste material or contaminated land is made much easier if analytical measurements can be made rapidly on site, and the new SPECTRO xSORT is a portable hand-held EDXRF instrument ideal for this type of work. The SPECTRO XEPOS is a high performance laboratory EDXRF system especially suitable for the determination of trace elements.

Metallic elements can be present in pharmaceutical products for a number of reasons, occurring as active ingredients, as impurities in raw materials and as contaminants. Some are known for their toxicity, and as such are tightly controlled by regulation. Because of the repetitive dosing involved in most treatment regimes, permitted levels have to take into account the cumulative exposure to toxic elements, driving down the limits of detection required from analytical procedures. In examining materials, the ability to screen for a number of metallic elements at these low levels may be required. On the other hand, in products such as dietary supplements, some elements may be present at relatively high concentrations.

The ideal analytical techniques for the analysis of pharmaceutical products will therefore combine the ability to measure a wide range of elements at trace levels with the wide dynamic range needed to handle higher concentrations. Samples may vary from raw materials, intermediates, process chemicals and solvents to finished products, so analytical techniques must be able to handle a wide range of sample matrices. The US Food and Drug Administration has proposed two new general chapters concerning elemental impurity limits (232) and analytical procedures (233). Chapter 233 suggests two techniques: inductively coupled plasma–optical emission spectroscopy (ICP-OES) and inductively coupled plasma–mass spectrometry (ICP-MS) for these analyses. Instruments used will need to be validated and will have to demonstrate compliance with other quality protocols used in the pharmaceutical industry such as US FDA 21 CFR Part 11. The SPECTRO ARCOS and SPECTRO GENESIS represent the state of the art in ICP-OES technology. The results at the end of this paper illustrate their performance and suitability for the analysis of pharmaceuticals.

Huge quantities of waste oil and related wastes are generated each year. Properly collected and processed, these wastes can be a valuable energy source or be refined to produce usable products such as new lubricating oil. However waste oil is usually contaminated, because of its previous use, with water and other liquids, halogens and other elements including heavy metals. In most countries it is regarded as potentially hazardous waste and must be handled, processed and stored accordingly. Its transport, storage and ultimate uses are governed by a variety of direct and indirect national and international legislation and industry standards. A worldwide specialist industry has developed to collect, transport and process waste oil and to market the products derived from it. Elemental analysis is an essential part of the environmental protection and quality control procedures associated with the recycling of waste oil. The two analytical techniques most frequently used for elemental analysis in this industry are Energy Dispersive X-ray Fluorescence (EDXRF) spectrometry and Inductively Coupled Plasma – Optical Emission Spectrometry (ICP-OES). This paper describes these techniques and how the range of instruments from SPECTRO Analytical Instruments meet the current and future requirements for elemental analysis in the waste oil recycling industry. 

“Condition Monitoring” is essential to the efficient operation of large plant and machinery, and is the use of physical and chemical techniques to check engines and machinery for wear with the objectives of preventing costly equipment failure and optimizing maintenance programs. The elemental analysis of used lubricating oil is an integral part of condition monitoring: specialist service laboratories and plant operators will analyze hundreds of lubricant samples a day for a wide range of elements. Many techniques exist for this type of analysis, but only Inductively Coupled Plasma – Optical Emission Spectrometry (ICP-OES) has the speed and sensitivity to succeed in these high throughput applications.

A modern simultaneous ICP-OES instrument such as the SPECTRO ARCOS is capable of measuring over 60 samples per hour for a wide range of elements. Direct presentation to the instrument of a simply diluted oil sample is the preferred technique when speed is essential. Even then, however, sample preparation can be the rate limiting step: the sample must be measured (by volume or weight), quantitatively diluted, mixed and presented to the instrument, possibly with the addition of an internal standard or other reagent. With high sample throughput, performed manually this task is not only costly in manpower terms, it is also repetitive and therefore subject to human error.

A new and revolutionary system developed jointly by SPECTRO Analytical Instruments and LABIRON Systems bv. fully automates the complete sample preparation and measurement process and achieves analysis times of less than one minute per sample including sample preparation. This paper examines the analytical requirements, the design and operation of the system.

Precious metals require — and reward — careful analysis. But analysts face various difficulties. The scope of precious metals analysis extends from trace levels to 100%. Most of these metals are resistant to dissolution by all but the strongest acids. Some traditional analytical methods like fire assay are time-consuming and demand a high level of skill.

Three modern techniques offer widely used solutions. Energy-dispersive X-ray fluorescence (ED-XRF) and optical emission spectrometry (OES) can be used without specialist analytical training to rapidly and accurately analyze bullion, jewelry, and alloys. A variation of OES, inductively coupled plasma optical emission spectrometry (ICP-OES), is an ideal tool for the analysis of bulk materials such as ores, and for the determination of trace impurities.

Several instruments available from SPECTRO Analytical Instruments represent the state of the art in these techniques. This paper describes their application to precious metals analysis.