Journal of Analytical & Bioanalytical Techniques
Open Access

Atomic absorption techniques; Elemental analysis; Absorption lines; Light source; Hollow cathode lamp

Introduction

Atomic absorption spectroscopy (AAS) stands as one of the most fundamental and widely used analytical techniques in various scientific disciplines, including chemistry, environmental science, geology, and materials science. It provides a powerful means of quantitatively analyzing the elemental composition of a sample, offering unparalleled sensitivity and selectivity [1].

At its core, atomic absorption spectroscopy operates on the principle of how atoms absorb light at specific wavelengths. When atoms in the gaseous state are exposed to a light source with a specific wavelength corresponding to the energy required to promote electrons to higher energy levels, they absorb photons of that particular energy [2]. By measuring the absorption of light by atoms at these characteristic wavelengths, the concentration of specific elements in a sample can be accurately determined.

The technique encompasses various methods and instrumentation configurations, each tailored to specific analytical requirements and sample matrices. Flame atomic absorption spectroscopy (FAAS) is one of the most traditional forms, utilizing a flame to atomize and excite the sample. Meanwhile, graphite furnace atomic absorption spectroscopy (GFAAS) provides enhanced sensitivity by atomizing the sample within a graphite furnace, thereby enabling analysis at lower concentrations [3].

Over the years, advancements in technology have led to the development of newer techniques such as cold Vapor atomic absorption spectroscopy (CVAAS) for the determination of mercury and hydride generation atomic absorption spectroscopy (HGAAS) for the analysis of elements like arsenic, antimony, and selenium.

The versatility and robustness of atomic absorption techniques have made them indispensable tools in analytical laboratories worldwide [4]. Their applications span a broad spectrum of industries, including environmental monitoring, pharmaceuticals, food and beverage analysis, forensic science, and metallurgy.

Discussion

Atomic absorption spectroscopy (AAS) is a powerful analytical technique used for the qualitative and quantitative analysis of elements in various samples. It relies on the principle of absorption of light by ground-state atoms in the gas phase. As the sample is atomized and introduced into the flame or a heated graphite furnace, atoms absorb light at specific wavelengths corresponding to the energy transitions of the elements being analyzed [5]. This absorption is measured and correlated with the concentration of the element in the sample.

The discussion on atomic absorption techniques encompasses several key aspects, including instrumentation, methodology, applications, and recent advancements:

Instrumentation: Modern AAS instruments consist of several key components, including a light source (usually a hollow cathode lamp specific to the element of interest), a monochromatic to isolate the desired wavelength, a sample introduction system (such as a nebulizer for liquid samples or a solid sample introduction device), and a detector to measure the absorption signal. Additionally, newer instruments may incorporate automation features for enhanced efficiency and data handling capabilities [6].

Methodology: The methodology of AAS involves several steps, beginning with sample preparation to ensure proper atomization and accurate results. Liquid samples are typically diluted to an appropriate concentration, while solid samples may require digestion or dissolution. The sample is then introduced into the atomization device, where it undergoes thermal decomposition and atomization. The absorption of light by the resulting atoms is measured, and the concentration of the analytes is determined using a calibration curve constructed from standards of known concentration [7].

Applications: Atomic absorption techniques find widespread applications across various fields, including environmental analysis, pharmaceuticals, food and beverage industry, clinical chemistry, and metallurgy. In environmental analysis, AAS is used to measure trace metals in water, soil, and air samples, aiding in environmental monitoring and regulatory compliance. In the pharmaceutical industry, AAS helps ensure the quality and safety of drugs by detecting impurities and verifying elemental composition. Similarly, in the food industry, it is employed to determine the presence of toxic elements or nutritional content in food products. Additionally, AAS is utilized in forensic analysis, geological exploration, and research laboratories for a wide range of elemental analyses [8, 9].

Recent advancements:

Recent advancements in atomic absorption techniques have focused on improving sensitivity, selectivity, and automation. Techniques such as hydride generation AAS and cold Vapor AAS extend the applicability of AAS to elements with limited volatility or in complex matrices. Moreover, the integration of AAS with other analytical techniques, such as chromatography or mass spectrometry, enables enhanced sample characterization and elemental speciation. Furthermore, developments in instrumentation, such as simultaneous multielement analysis and miniaturization of components, contribute to faster analysis times and lower detection limits [10].

Conclusion

Atomic absorption techniques continue to play a vital role in analytical chemistry, offering precise and reliable measurements of elemental concentrations in diverse samples. With ongoing advancements in instrumentation and methodology, AAS remains a cornerstone technique for elemental analysis across various industries and research fields.

1. Von-Seidlein L, Kim DR, Ali M, Lee HH, Wang X, Thiem VD, et al. (2006) A multicentre study of Shigella diarrhoea in six Asian countries:  Disease burden, clinical manifestations, and microbiology. PLoS Med 3: e353.

Google Scholar, Crossref, Indexed at

2. Germani Y, Sansonetti PJ (2006) The genus Shigella. The prokaryotes In:  Proteobacteria:  Gamma Subclass Berlin:  Springer 6: 99-122.

Google Scholar

3. Aggarwal P, Uppal B, Ghosh R, Krishna Prakash S, Chakravarti A, et al. (2016) Multi drug resistance and extended spectrum beta lactamases in clinical isolates of Shigella:  a study from New Delhi, India. Travel Med Infect Dis 14: 407–413.

Google Scholar, Crossref, Indexed at

4. Taneja N, Mewara A (2016) Shigellosis:  epidemiology in India. Indian J Med Res 143: 565-576.

Google Scholar, Crossref, Indexed at

5. Farshad S, Sheikhi R, Japoni A, Basiri E, Alborzi A (2006) Characterizationof Shigella strains in Iran by plasmid profile analysis and PCR amplification of ipa genes. J Clin Microbiol 44: 2879–2883.

Google Scholar, Crossref, Indexed at

6. Jomezadeh N, Babamoradi S, Kalantar E, Javaherizadeh H (2014) Isolation and antibiotic susceptibility of Shigella species from stool samplesamong hospitalized children in Abadan, Iran. Gastroenterol Hepatol Bed Bench 7: 218.

Google Scholar, Indexed at

7. Sangeetha A, Parija SC, Mandal J, Krishnamurthy S (2014) Clinical and microbiological profiles of shigellosis in children. J Health Popul Nutr 32: 580.

Google Scholar, Indexed at

8. Ranjbar R, Dallal MMS, Talebi M, Pourshafie MR (2008) Increased isolation and characterization of Shigella sonnei obtained from hospitalized children in Tehran, Iran. J Health Popul Nutr 26: 426.

Google Scholar, Crossref, Indexed at

9. Zhang J, Jin H, Hu J, Yuan Z, Shi W, Yang X, et al. (2014) Antimicrobial resistance of Shigella spp. from humans in Shanghai, China, 2004–2011. Diagn Microbiol Infect Dis 78: 282–286.

Google Scholar, Crossref, Indexed at

10. Pourakbari B, Mamishi S, Mashoori N, Mahboobi N, Ashtiani MH, Afsharpaiman S, et al. (2010) Frequency and antimicrobial susceptibility of Shigella species isolated in children medical center hospital, Tehran, Iran, 2001–2006. Braz J Infect Dis 14: 153–157.

Google Scholar, Crossref, Indexed at