Mass spectroscopy sample introduction

To examine a sample by inductively coupled plasma mass spectrometry (ICP/MS) or inductively coupled plasma atomic-emission spectroscopy (ICP/AES) the sample must be transported into the flame of a plasma torch. Once in the flame, sample molecules are literally ripped apart to form ions of their constituent elements. These fragmentation and ionization processes are described in Chapters 6 and 14. To introduce samples into the center of the (plasma) flame, they must be transported there as gases, as finely dispersed droplets of a solution, or as fine particulate matter. The various methods of sample introduction are described here in three parts — A, B, and C Chapters 15, 16, and 17 — to cover gases, solutions (liquids), and solids. Some types of sample inlets are multipurpose and can be used with gases and liquids or with liquids and solids, but others have been designed specifically for only one kind of analysis. However, the principles governing the operation of inlet systems fall into a small number of categories. This chapter discusses specifically substances that are normally liquids at ambient temperatures. This sort of inlet is the commonest in analytical work. 

Elemental Spedation - New Approaches for Trace Element Analysis Discrete Sample Introduction Tbchniques for Inductively Coupled Plasma Mass Spectrometry Modem Fourier Transform Infrared Spectroscopy Chemical Test Methods of Anal3rsis... 

Magnetic sector instruments are further distinguished by their method of sample introduction - how the sample is put into the electromagnetic field. Many instruments today use a plasma, identical to that in optical ICP spectroscopy (ICP-MS). In the mass spec, the plasma is used to ionize the atoms. Although the plasma emits the characteristic spectra used in ICP-OES, this visible light output is not used by the mass spectrometer. Figure 4.25 shows the ICP-MS in the Laboratory for Archaeological Chemistry at the University of Wisconsin-Madison. 

Pyrolysis coupled with gas chromatography - mass spectroscopy (Py-GC-MS) in an inert atmosphere has been used to study thermal degradation products of styrene-butadiene rubber (SBR). Introduction of samples, using the pyrolysis carrier... 

Giinther, D., Jackson, S.E., Longerich, H.P. (1999) Laser ablation and arc/spark sohd sample introduction into inductively coupled plasma mass spectrometers. Spectrochimica Acta Part B Atomic Spectroscopy, 54,381-409. 

Another method included in this chapter is ICP-MS, which, although not based on atomic spectroscopy in a true sense, utilizes the same instrumental approach as ICP-AES for sample introduction. The difference is that analyte quantification takes place using a mass spectroscopy detector. 

Sneddon, 1. (1990) Sample Introduction in Atomic Spectroscopy, Elsevier, New York. Montaser, A. (ed.) (1998) Inductively Coupled Plasma Mass Spectrometry, Wiley-VCH, New York. 

Atomic spectroscopy is widely used in inorganic chemistry to determine total element concentrations in many sample types, and generally allows rapid sample throughput. The optical techniques allow determination of atomic concentrations down to sub ng/ml levels (10" M and below) in samples of a few millilitres or less. The recent introduction of a new mass spectrometric technique allows isotope-specific measurements to be made with the ease of use and sample throughput of the atomic spectroscopic techniques. 

Tt may be safe to say that the interest of environmental scientists in airborne metals closely parallels our ability to measure these components. Before the advent of atomic absorption spectroscopy, the metal content of environmental samples was analyzed predominantly by wet or classical chemical methods and by optical emission spectroscopy in the larger analytical laboratories. Since the introduction of atomic absorption techniques in the late 1950s and the increased application of x-ray fluorescence analysis, airborne metals have been more easily and more accurately characterized at trace levels than previously possible by the older techniques. These analytical methods along with other modem techniques such as spark source mass spectrometry and activation analysis... 

---