Special Issues-10-01-2006

Accurate determination of trace Cl, Br, and I is important in industries such as petrochemical refining, chemical manufacturing, biomedical and nutritional supplement manufacturing, and environmental analysis. Until recently, it was thought that the halogen elements could not be determined effectively by inductively coupled plasma–optical emission spectroscopy (ICP-OES); however, with recent advances in spectrometer and detector design, these elements are now readily determined. In fact, ICP-OES offers many advantages for the measurement of Cl, Br, and I. These include ease-of-use and the ability to test for other elements simultaneously, along with good sensitivity, precision, and accuracy. This article describes the measurement of chlorine in tissue and oil samples as well as the measurement of bromine in plastics and electronic materials where the solids were sampled using laser ablation.

Interactive dedicated tools have been developed to facilitate the use of multiline analysis in inductively coupled plasma–atomic emission spectroscopy (ICP-AES) with emphases on multiline selection and on statistics for rejection of possible outliers. The aim is to take full benefit of the available information when using a charge-coupled device (CCD) detector–based instrument and to enhance the accuracy of the results. Determination of Cu in steel will be used to illustrate the potential of the tools.

The use of fertilizers is important to increase crop yields in soils that are being used for agricultural purposes. However, in order to maximize plant growth, it is also absolutely essential to know how the crops are using the nutrients in the soil. This process is commonly referred to as a fertility management program, where many soil samples are taken over a predefined area of the land and analyzed for various components such as pH, organic matter, and trace element nutrients. This article describes how a soil testing laboratory in the midwest has developed a method to analyze up to 3500 soil samples per day for 11 trace metals, using inductively coupled plasma–optical emission spectroscopy. It will focus on the soil sampling procedure together with the sample preparation requirements for this high workload environment. The instrumental analytical procedure will be described in greater detail, particularly how the measurement protocol and sampling process are optimized to cope with such extreme..

Special Issues

The analysis of edible oils and fats by inductively coupled plasma–optical emission spectroscopy (ICP-OES) utilizing direct injection after dilution with kerosene is described. Sample preparation was performed according to EN ISO 661 (1) and ISO 10540-3 (2). The accuracy was investigated using the AOCS reference sample, "Trace Metals in Soybean Oil" (3) and by spike recovery measurements using commercial sunflower oil. The analysis requirements for sensitivity, precision, and accuracy were met. This article includes line selection, detection limits, and accuracy studies.

Although inductively coupled plasma–mass spectrometry (ICP-MS) has rapidly attained acceptance as the choice in trace metal analysis, most commercially available instruments are equipped with quadrupole-based mass analyzers. Quadrupole mass spectrometers have been available commercially for ICP since the early 1980s. Modifications and advances in these types of instruments predominantly have been in the sample introduction and ion optic areas, leaving the quadrupole mass spectrometer untouched.

Fertilizers are used to provide major plant nutrients (N, P, and K), secondary plant nutrients (Ca, S, and Mg), and micronutrients such as B, Mn, Fe, Cu, Zn, Mo, and Se. Accurate determination of the composition of fertilizers is essential so that the correct dose can be applied to the soil. An insufficient application of a fertilizer can result in poor crop yield, and an excessive application can result in environmental damage such as eutrophication by dissolved phosphates and nitrates entering water courses or land contamination from nonnutrient elements within the fertilizers. Inductively coupled plasma (ICP) spectroscopy offers cost-effective analysis of fertilizers because of its multielement capabilities. Complex torch designs and sparging systems have been employed in the past to determine nitrogen by ICP spectroscopy, but these additions to ICP instrumentation are costly and prolong analysis time.