An in-depth review of analytical methods for cadmium detection in seawater through graphite furnace atomic absorption spectrometry

Abstract Cadmium is a highly toxic heavy metal that poses significant risks to marine ecosystems, necessitating accurate trace-level measurement in seawater. Graphite Furnace Atomic Absorption Spectroscopy (GFAAS) is highly sensitive for detecting Cd but faces challenges due to seawater's complex matrix, which can cause spectral interferences and matrix effects. This review covers the development of GFAAS methods for direct Cd determination in seawater from 1977 to the present, focusing on pre-concentration and matrix modification techniques to address these challenges. Pre-concentration methods enhance detection sensitivity by concentrating large seawater volumes into smaller samples, enabling trace metal analysis. This review evaluates various pre-concentration techniques, including solvent extraction, cloud point extraction, solid phase extraction, hollow fiber-supported liquid membrane extraction and Dispersive Liquid–Liquid Microextraction. Each method's advantages, limitations, and applications are discussed. Advancements in matrix modification and furnace programming have also improved direct Cd determination. Matrix modifiers enhance Cd signal intensity and reduce background noise. Background correction techniques, like Zeeman background correction, are crucial for mitigating spectral interferences. The review highlights the effectiveness of these approaches and the potential of temperature-programmed selective volatilization for improved Cd atomization and interference reduction. Future research should focus on developing novel matrix modifiers with better selectivity and minimal interference, and exploring hyphenated techniques like GFAAS-HPLC or GFAAS-ICP-MS for enhanced detection. The review underscores the need for ongoing innovation and the exploration of eco-friendly pre-concentration methods and advanced analytical techniques for accurate Cd detection in seawater, crucial for marine environmental monitoring and management.