CHM026 Topic IB_Introduction Environmental Analytical Chemistry

Introduction to Environmental Analytical Chemistry

• Course Title: Environmental Analytical Chemistry (CHM026 Topic IB)

• Institution: Mindanao State University, Iligan Institute of Technology

• Academic Year: 2nd Semester 2024-2025

Historic Perspectives and Scopes

• Definition: Environmental Analytical Chemistry combines aspects of analytical and environmental chemistry.

  • Analytical Chemistry: Study of separation, identification, and quantification of chemical components (natural/synthetic).

  • Environmental Analytical Chemistry: Focus on chemical components significant to the environment and their impact.

Relationship to Environmental Chemistry

• Environmental Chemistry defined as a study involving:

  • Contaminant behavior (pollution chemistry)

  • Analysis (pertaining to environmental analytical chemistry)

  • Chemical control technology (pollution control chemistry)

• Environmental Analytical Chemistry: Sub-discipline of environmental chemistry.

Evolution of Environmental Analytical Chemistry

• Evolved from traditional analytical chemistry to a distinct discipline.

• Attracts diverse professionals (scientists, engineers, chemists, educators).

• Involves:

  • Sample representation and collection challenges.

  • Sample preparation from complex matrices.

  • Instrumental qualification and quantification of contaminants at very low levels (ppm to ppq).

  • Compliance with regulatory requirements for various environmental mediums (drinking water, wastewater, air, hazardous wastes).

Traditional and Modern Methods in Environmental Chemistry

• Traditional Instrumental Methods:

  • Spectroscopic

  • Chromatographic

  • Mass spectrometric

  • Electrochemical

  • Thermal

  • Radiological

• Other Methods:

  • Bioanalytical methods (e.g., immunoassays, biosensors).

Environmental Sampling Techniques

• Importance of representative sampling:

  • Cost-effective sampling design strategies.

  • Comparison: Grab/Active sampling vs. Passive diffusion-based sampling.

  • Goals of sample preparation: Discuss digestion procedures for inorganic metals and extraction methods for volatile/semi-volatile compounds.

Perspectives and Challenges in the Field

• Urgent needs:

  • Advanced sampling methodologies for real-world applications.

  • Innovations in instrumentation for enhanced speed, sensitivity, and affordability.

  • Development of miniature sensing devices for real-time monitoring.

Unique Features of Environmental Analytical Chemistry

• Distinguishes itself from traditional analytical chemistry in multiple aspects:

  • Low concentration levels of analytes.

  • Complex sample matrices.

  • High sampling and analytical costs.

  • Increasing demand for in-situ monitoring and automation.

  • Subject to various laws and regulations.

Scopes and Organizational Framework

• Applied analytical chemistry focused on environmental pollutants.

• Measurement tools for qualifying and quantifying pollutants, encompassing chemical, biological, thermal, radiological, and other physical parameters of interest.

Analytical Chemistry Intersection

• Environmental Analytical Chemistry interfaces with various disciplines, focusing on:

  • Inorganic and organic contaminants.

  • Biological and toxicological parameters.

  • Radiological parameters.

  • Environmental matrices including air, water, solid waste, and biological samples.

Classification of Analytical Methods

• Analytical Methods Classification:

  • Classical methods: Wet-chemical methods, both qualitative and quantitative.

  • Instrumental methods:

    • Measured physical properties include conductivity, electrode potential, light absorption/emission, and mass-to-charge ratio.

    • Growth in instrumental methods due to technological advancements in electronics and computing.

Instrumental Methods Overview

• Types of Instrumental Methods:

  • Characteristic properties for instrumental analysis include:

    • Emission, absorption, and scattering of radiation.

    • Electrical potentials, currents, and resistance.

    • Mass, thermal characteristics, and radioactivity.

Calibration Procedures in Instrumental Methods

• Calibration is essential for accuracy and includes:

  • External standard calibration vs. internal standard methods.

  • Errors related to external standards, including matrix effects and inaccuracies.

  • Standard Addition Method: Useful in supporting complex sample analysis with potential matrix interference.

Performance Characteristics of Instruments

• Factors influencing instrument performance:

  • Precision, bias, sensitivity, detection limits, dynamic range, and selectivity.

  • Defining a problem effectively is crucial for method selection.

Understanding Sampling Importance

• Representative samples are vital for accurate environmental analysis, drawing from broader scientific disciplines.

• Challenges in awareness and techniques related to sampling have persisted, leading to systematic environmental data acquisition errors.

Challenges in Environmental Analytical Chemistry

• Addressing human-induced waste impacts on ecosystems.

  • Historical negligence in stewardship improved by regulatory measures and research advancements.

  • Future needs include enhanced analytical sensitivity and improved methodologies to address environmental issues not yet fully understood.

Signal and Noise Considerations

• Key concepts: Separation of signal (analyte information) from noise (extraneous information affecting analysis accuracy).

• Enhancing signal-to-noise ratio through hardware and software methods.

References

• Fifield, F.W. & Haines, P.J. Environmental Analytical Chemistry, 2nd ed. Blackwell Science, 2000.

• Zhang, C. Environmental Analytical Chemistry, 2007.

• Gaffney, J.S. & Marley, N.A. Chemistry of Environmental Systems, 1st ed. John Wiley & Sons Ltd., 2020.

• D.A. Skoog et al. Fundamentals of Analytical Chemistry, 9th ed. Brooks/Cole, Cengage Learning, USA 2014.

• Christian, G.D. Analytical Chemistry, 7th ed. New York: John Wiley and Sons, 2013.