Introduction
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has gained significant popularity as well as extreme attention over the last couple of years due to its benefits and positive attributes. LA-ICP-MS has been extensively used in the analysis of biological samples, chemical samples and gemology. The technique of laser ablation inductively coupled plasma mass spectrometry is a significant technique for quantitative chemical analysis (Becker, 2013). Due to its numerous advantages such as rapid and direct analysis of samples, high sensitivity and high spatial resolution, it has been applied in numerous applications in different fields apart from chemistry.
The use and application of laser ablation inductively coupled mass spectrometry enables the establishment and determination of isotopes and elements in biological tissues and related tissues using a spatial resolution that ranges from 10 to 100 micrometres. As compared to the other techniques employed in obtaining bio images, laser ablation inductively coupled plasma mass spectrometry has a higher sensitivity (Szymanski, 2004). Apart from its high sensitivity, laser ablation inductively coupled plasma mass spectrometry has several advantages other techniques. As compared to the other inorganic mass spectrometric methods, laser ablation inductively coupled plasma mass spectrometry contributes significantly as a sensitive and powerful micro-analytical technique. The use and application of this technique allow for the analysis of multi-element trace as well as the measurement of isotope ratio at both ultra-trace and trace levels.
Operation of LAI-CP-MS
The samples in laser ablation inductively couple plasma mass spectrometry are analysed directly through direct ablation using a pulsed laser beam. After ablation, the generated aerosols are relayed into the centre inductively coupled argon plasma which produces high temperature close to 8000 degree Celsius. The plasma present in inductively coupled plasma mass spectrometry is utilised to produce ions which are introduced to the mass analyser. The mass to charge ratio of this ion are used to separate and collect them (Becker, 2005. This technique allows for the identification and measurement of the components of the unknown sample under analysis. The application of laser ablation inductively coupled plasma mass spectrometry presents high sensitivity to a myriad of elements.
An additional advantage that contributes to the popularity and extensive application of laser ablation inductively coupled plasma mass spectrometry techniques is the fact that any solid sample can be prepared and ablated for analysis (Morrison et al., 2004). This technique of substance micro-analysis does not discriminate solid samples presented for analysis. It does not have any sample size requirements or any procedure for preparing the samples. It is worth noting the use and application of laser ablation inductively coupled plasma mass spectrometry in chemical analysis require the use of small amount of samples in micrograms. This amount is smaller than the amount required for nebulization (Becker, 2013). As opposed to chemical analysis, the nebulization requires amounts in the form of milligrammes. This technique requires very small amount of sample for analysis depending on the analytical measurement system. Furthermore, it is equipped with a focused laser beam which allows for spatial categorization of heterogeneity in solid samples. It accomplishes the characterization of heterogeneity is solid samples using micro resolution regarding depth conditions and lateral conditions alike.
Usefulness, Strength and limitation of LAI-CP-MS
It is imperative to note of the strengths and limitations associated with the use and application of laser ablation inductively coupled plasma mass spectrometry technique. The technique allows for the direct sampling of multi-element semi-quantification or quantitative at the surface as well as bulk for an elemental opus of solids. Also, this technique to quantitative chemical analysis does not require the use of the chemical process for dissolution. As compared to the use of traditional techniques, the application and use of laser ablation inductively coupled plasma mass spectrometry technique presents minimal risk to the loss of analyte or cross contamination. Furthermore, the application and use of this technique present the analysis of chemicals with independent of sample geometry (Becker, 2005).It allows for the establishment of the spatial distribution of the composition of elements under analysis. Apart from the high sensitivity in chemical element analysis, the use of laser ablation inductively coupled plasma mass spectrometry enables the analysis of very small samples without discrimination.
While the application of LAI-CP-MS presents numerous advantages that deem useful in numerous applications, it has several limitations which must be addressed so as to enjoy its full potential in the quantitative chemical analysis (Morrison et al., 2004). The use of laser ablation inductively coupled plasma mass spectrometry technique present two major pitfalls in chemical analysis. It is apparent that it is used in the analysis of various elements. The molecular species, as well as the common matrix elements, has the ability to interfere with the analysis and determination of some elements. Additionally, there is difficulty in quantification generated by some molecular species or doubly charged elements.
Future Developments and Applications of LAI-CP-MS
The benefits and attributes associated with the use of LAI-CP-MS enable the technique to be applied in the various field for different applications. The technique has been extensively used in the determination of isotopes and elements in biological tissues as well as related materials due to its spatial resolution (Szymanski, 2004). Furthermore, the technique has been applied in gemology to exploit the benefits associated with its application such as direct and rapid analysis of gemstones, high spatial resolution as well as precise measurement of a myriad of elements (Morrison et al., 2004). The popularity of the technique has enabled its extensive use in forensic analysis, elemental distribution analysis, contamination, failure and inclusion analysis, mineral and environmental sample analysis, contamination of pharmaceuticals, plastics and biological materials. Also, the technique is used in minor, trace and major level compositional analysis of semi-conductive, conductive and non-conductive materials.
References
Becker, J. (2013). Imaging of metals in biological tissue by laser ablation inductively coupled
plasma mass spectrometry (LA-ICP-MS): state of the art and future developments.
Becker, J. (2005). Inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation
ICP-MS for isotope analysis of long-lived radionuclides. International Journal Of Mass
Spectrometry, 242(2-3), 183-195.
Morrison, G., Fatoki, O., Linder, S., & Lundehn, C. (2004). Determination of Heavy Metal
Concentrations and Metal Fingerprints of Sewage Sludge from Eastern Cape Province,
South Africa by Inductively Coupled Plasma – Mass Spectrometry (ICP-MS) and Laser
Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS). Water, Air, &
Soil Pollution, 152(1-4), 111-127
Szymanski, D. (2004). The use of laser ablation inductively coupled plasma mass spectrometry
(LA-ICP-MS) for the discrimination of glass fragments in forensic casework.
