Inductively coupled plasma mass detection limits

The complex of the following destmctive and nondestmctive analytical methods was used for studying the composition of sponges inductively coupled plasma mass-spectrometry (ICP-MS), X-ray fluorescence (XRF), electron probe microanalysis (EPMA), and atomic absorption spectrometry (AAS). Techniques of sample preparation were developed for each method and their metrological characteristics were defined. Relative standard deviations for all the elements did not exceed 0.25 within detection limit. The accuracy of techniques elaborated was checked with the method of additions and control methods of analysis. 

Inductively coupled plasma-mass spectrometry (ICP-MS) is a multielement analytical method with detection limits which are, for many trace elements, including the rare earth elements, better than those of most conventional techniques. With increasing availability of ICP-MS instalments in geological laboratories this method has been established as the most prominent technique for the determination of a large number of minor and trace elements in geological samples. 

In modern times, most analyses are performed on an analytical instrument for, e.g., gas chromatography (GC), high-performance liquid chromatography (HPLC), ultra-violet/visible (UV) or infrared (IR) spectrophotometry, atomic absorption spectrometry, inductively coupled plasma mass spectrometry (ICP-MS), mass spectrometry. Each of these instruments has a limitation on the amount of an analyte that they can detect. This limitation can be expressed as the IDL, which may be defined as the smallest amount of an analyte that can be reliably detected or differentiated from the background on an instrument. 

ICP-MS (inductively coupled plasma mass spectrometry) is frequently used for determining ultratrace amounts of technetium [9]. In spite of the high cost of the equipment, this detection method is far superior to other radiometric methods as regards sensitivity. When a double focussing high-resolution system is used (HR-ICP-MS) and an ultrasonic nebulizer is introduced [10], the detection limit is in the order 0.002 mBq. The ICP-MS method has been successfully applied to the determination of environmental "Tc as well as to other long-lived radionuclides of neptunium and plutonium in the environment. 

Yang et al. [83] accomplished speciation of organotin compounds using reverse-phase liquid chromatography with inductively coupled plasma mass spectrometric detection. The separation was complete in 6min and detection limits were in the range 2.8-16pg of tin for various species. 

The major anions and cations in seawater have a significant influence on most analytical protocols used to determine trace metals at low concentrations, so production of reference materials in seawater is absolutely essential. The major ions interfere strongly with metal analysis using graphite furnace atomic absorption spectroscopy (GFAAS) and inductively coupled plasma mass spectroscopy (ICP-MS) and must be eliminated. Consequently, preconcentration techniques used to lower detection limits must also exclude these elements. Techniques based on solvent extraction of hydrophobic chelates and column preconcentration using Chelex 100 achieve these objectives and have been widely used with GFAAS. 

Soil samples were wet sieved into (a) 2-4 mm, (b) 1-2 mm, (c) 0.5-1 mm, (d) 250-500 i m, (e) 125-250 am, (f) 63-125 j,m and (g) <63 j.m fractions. A ferruginous/magnetic fraction (m) was also prepared from the 2-4 mm fraction. Soil fractions were crushed, digested with HNO3/HCI/HF/HCIO4 and then analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) for Al, Ca, Cu, Fe, K, Mn, Na, P, S and Zn. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to determine Ag, As, Cd, Pb and Sb because of the lower detection limits by this method. The mineralogy of selected samples was determined by qualitative X-ray diffractometry. 

Cations were determined by high-resolution inductively coupled plasma-mass spectrometry (HR-ICPMS), relatively new analytical instrumentation with a large dynamic range and detection limits (DLs) in the low (1-50) parts per trillion (ppt) for most elements. The exceedingly low DLs allow for recognition of elemental variations that are not possible with traditional analytical methods for water. 

In 1C, the election-detection mode is the one based on conductivity measurements of solutions in which the ionic load of the eluent is low, either due to the use of eluents of low specific conductivity, or due to the chemical suppression of the eluent conductivity achieved by proper devices (see further). Nevertheless, there are applications in which this kind of detection is not applicable, e.g., for species with low specific conductivity or for species (metals) that can precipitate during the classical detection with suppression. Among the techniques that can be used as an alternative to conductometric detection, spectrophotometry, amperometry, and spectroscopy (atomic absorption, AA, atomic emission, AE) or spectrometry (inductively coupled plasma-mass spectrometry, ICP-MS, and MS) are those most widely used. Hence, the wide number of techniques available, together with the improvement of stationary phase technology, makes it possible to widen the spectrum of substances analyzable by 1C and to achieve extremely low detection limits. 

Li or a Li compound in the flame gives a bright crimson color due to its emission of670.8 nm photons produced by the short-lived species LiOH. This is the property that allows for the spectrophotometric determination of Li by atomic absorption spectroscopy (AAS) down to 20 ppb. Inductively-coupled plasma emission spectroscopy (ICPAES), inductively-coupled plasma mass spectroscopy (ICPMS), and ion chromatography (IC) improve this limit to about 0.1 ppb. A spot test for detection of Li down to 2 ppm is provided by basic KIO4 plus FeCl3. 

Figure 21-24 Flame, furnace, and inductively coupled plasma emission and inductively coupled plasma—mass spectrometry detection limils (ng/g = ppb) with instruments from GBC Scientific Equipment, Australia. [Flame, furnace. ICP from R. J. Gill. Am. Lab. November 1993, 24F. ICP-MS from T. T. Nham, Am. Lab. August 1998. 17A Data for Ct Br, and l are from reference 14.] Accurate quantitative analysis requires concentrations 10-100 times greater than the detection limit.

Inorganic pigments and lakes (organic dyes bonded to an inorganic support) can be recognized by the ratio of elements in their composition, making elemental analysis an important tool in their identification. EDS may facilitate an initial qualitative analysis, but quantitative analysis and the detection of trace elements are needed to identify the inorganic colorant components. Due to sample size restrictions, the methods that can be employed are limited. The techniques of inductively-coupled plasma mass spectrometry (ICP-MS), ICP-optical emission spectroscopy (ICP-OES), and laser ablation ICP-MS are described in the literature (56). 

Several other microanalytical methods in common use potentially have application on soil and sediments section samples. Laser-ablation inductively coupled plasma mass spectrometery (LA-ICP-MS) has been used on soil thin-sections from a controlled field experiment (21) but required special resins in the preparation. There is presently (May 2006) no reported use of this method on archaeological soil samples. Likewise, for extremely fine-resolution studies (i.e. <10 pm) with low minimum detection limits and despite difficult calibration, secondary ion microscopy (SIMS) has a potential role in examining archaeological soil thin sections. At even higher lateral resolutions ( 100 nm) Auger electron spectroscopy (AES) could also be considered for surface (<5 nm deep) analyses. At present however, the use of these methods in soil systems is limited. SIMS has been focused on biochemical applications (22), whereas AES... 

In the test method, the coal or coke to be analyzed is ashed under controlled conditions, digested by a mixture of aqua regia and hydrofluoric acid, and finally dissolved in 1% nitric acid. The concentration of individual trace elements is determined by either inductively coupled plasma-atomic emission spectrometry (ICPAES) or inductively coupled plasma-mass spectrometry (ICPMS). Selected elements that occur at concentrations below the detection limits of ICPAES can be analyzed quantitatively by graphite furnace atomic absorption spectrometry (GFAA). 

Inductively coupled plasma mass spectrometry has been used for the analysis of uranium. However, the technique suffers from spectral interferences and it has relatively poor detection limits. 

Inductively coupled plasma mass spectrometry is a relatively new technique for elemental analysis and has superior limits of detection over optical methods. Also, this technique has an order of magnitude better detection limit than that obtained by the conventional fluorometric method. Uranium has many stable and unstable isotopes but 238U has the largest percentage abundance (99.274%). 

The determination of 129I in low-level radioactive waste was accomplished by radioactive instrumental neutron activation analysis [3]. A different group reported the determination of both 129I and 127I by neutron activation analysis and inductively coupled plasma mass spectrometry [4]. The method was very rapid - a sample could be analysed in three minutes. However, interference from 129Xe resulted in limited sensitivity for 129I detection. 

Inductively coupled plasma-mass spectrometry (ICP-MS) is a powerful technique that uses an inductively coupled plasma as an ion source and a mass spectrometer as an ion analyzer. It can measure the presence of more than 75 elements in a single scan, and can achieve detection limits down to parts per trillion (ppt) levels for many elements—levels that are two or three orders of magnitude lower than those obtained by ICP-AES (Keeler 1991). It is more expensive than ICP-AES and requires more highly skilled technical operation. Aluminum levels in urine and saliva were detected down to 0.02 g/mL and in blood serum to 0.001 g/mL using ICP-MS (Ward 1989). Speciation studies have employed ICP-MS as a detector for aluminum in tissue fractions separated by size-exclusion chromatography (SEC) with detection limits of 0.04 g/g in femur, kidney and brain (Owen et al. 1994). 

IATA ICAP ICP ICP-AES ICP-MS ICV ID IDL IDW ISO International Air Transportation Association inductively coupled argon plasma inductively coupled plasma inductively coupled plasma-atomic emission spectrometry inductively coupled plasma-mass spectrometry initial calibration verification identification instrument detection limit investigation-derived waste International Standardization Organization... 

Iron-containing compounds in biological and clinical samples have been studied by separating them on chromatographic columns that were coupled to inductively coupled plasma mass spectrometers. Four iron-containing proteins, namely ferritin, haemoglobin, myoglobin and cytochrome-c were separated on a gel permeation column (Takatera and Watanabe, 1991). The absolute detection limits were 0.01-1 mg for the four proteins when 10 ml injections of samples were analysed. In other research, excess iron accumulations in human and animal... 

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