Chemical Analysis in Environmental Chemistry Petra Booij booij@recetox.muni.cz Previous lectures • Semi-volatile organic compounds – from sources to the environment - Part 1: Chlorinated and brominated compounds - Part 2: Emerging compounds, endocrine disrupting compounds • Analytical chemistry - Monitoring and sampling strategies I This lecture • Analytical chemistry and environmental pollution • Steps in quantification of contaminants • Sample preparation and clean-up • Chromatography • Detection • Data processing • Examples • Case study Analytical Chemistry Quantitation How much of substance X is in the sample? Detection Does the sample contain substance X? Identification What is the identity of the substance X in the sample? Separation How can the compounds of interest be separated from the sample matrix for better quantitation and identification? Environmental Pollution - Sources Environmental Pollution - Effects Chemical Analysis of Environmental Samples compounds e.g., Pharmaceuticals Personal care products Drugs Biocides Polycyclic Aromatic Compounds Phthalates Antioxidants Halogenated compounds Dioxines Steps in a Quantitative Analysis Select method Obtain a representative sample Prepare a laboratory sample Define replicate samples Dissolve the sample Eliminate interferences Measure substance(s) Calculate results Estimate the reliability of results Selecting a Method • What is the problem? • What is already known? • Choosing a Method • Testing Procedure - Standard Sample - Comparing methods - Standard addition to the sample • Accuracy Sampling and Preparation • Sampling uncertainties • Representative • Homogene • Crushing, grinding, sieving, mixing • Replicates • Quanitative or Qualitative analysis Eliminating Interferences – Sample Clean-up • Solubility • Partition coefficient • Liquid/Liquid Extraction • Solid Phase Extraction (SPE) • Soxhlet Extraction • Accelerated Solvent Extraction (ASE) • Gel Permeation Chromatography (GPC) • Evaporation • Filtration History 1906 - Tswett - Adsorption Chromatography Solid Phase Extraction (SPE) Soxhlet Extraction Accelerated Solvent Extraction (ASE) Gel Permeation Chromatography (GPC) porous packing Adsorption Chromatography http://www.hitachi-hitec.com/global/science/lc/lc_basic_4.html Partition Chromatography http://www.hitachi-hitec.com/global/science/lc/lc_basic_4.html Ion Exchange Chromatography http://www.hitachi-hitec.com/global/science/lc/lc_basic_4.html High Performance Liquid Chromatography (HPLC) Gas Chromatography (GC) GC column Solid-phase microextraction (SPME) Fiber coated with extraction phase Vial containing sample (liquid or gas) Contaminants Detectors Often used in Environmental Chemistry: Fluorescence Detector UV-VIS detector Mainly used in Environmental Chemistry: Mass Spectrometry Analytical signals: Emission of radiation Absorption of radiation Scattering radiation Reflection of radiation Electrical current Electrical resistance Mass-to-charge ratio Fluorescence Detector http://www.hitachi-hitec.com/global/science/lc/lc_basic_4.html UV-VIS Detector http://www.hitachi-hitec.com/global/science/lc/lc_basic_4.html Mass Spectrometry (MS) Sample Data Ionization Source Mass Analyzer Ion Detector MS Chromatogram Retention time (min) Detectorsignal Intensity Peak Integration Retention time (min) Detectorsignal Intensity Peak RT Area Height 1 6.763 7496704442 779127844.4 2 8.532 5292010045 535611910.5 3 8.816 3649106823 394565640.2 1 2 3 Calibration Curve - Quantification y = 1E+09x + 2E+07 R² = 0.9864 0.0E+00 2.0E+08 4.0E+08 6.0E+08 8.0E+08 1.0E+09 1.2E+09 0 0.2 0.4 0.6 0.8 1 1.2 Peakintensity concentration (ng/ml) Calibration curve sample Mass Spectrum - Qualification Retention time (min) Detectorsignal Intensity Detectorsignal Intensity Errors • Instrument • Method • Personal Accuracy, Precision and Trueness Random and Systematic Errors Measurement Errors accuracy repeatability method bias laboratory bias random errors trueness precision reproducibility Eliminating Errors • Calibration • Proper use of standards • Proper use of internal labeled standards • Blank material • Reference material Extraction tools for identification of chemical contaminants in estuarine and coastal waters to determine toxic pressure on primary producers (Booij et al., Chemosphere 93 (2013) 107-114) Method: 1. SPE / Soxhlet 2. Evaporation 3. LC-MS Compounds: Herbicides The use of mosses and pine needles to detect persistent organic pollutants at local and regional scales (Holoubek et al., Environmental Pollution 109 (2000), 283-292) Method: 1. Drying 2. Mincing 3. Soxhlet 4. Evaporation 5. SPE 6. Evaporation 7. GC-MS Background site Industrial site Industrial site Compounds: Polycyclic Aromatic Hydrocarbons (PAHs) Contamination of Antarctic snow by polycyclic aromatic hydrocarbons dominated by combustion sources in the polar region (Kukučka et al., Environ. Chem. 7 (2010) 504–513) Method: 1. SPME 2. GC-MS Compounds: Polycyclic Aromatic Hydrocarbons (PAHs) PCDD, PCDF, PCB and PBDE concentrations in breast milk of mothers residing in selected areas of Slovakia (Chovancová et al, Chemosphere 83 (2011) 1383–1390) Method: 1. Sufuric acid/silica 2. SPE 3. GC-MS Compounds: Dioxins, Polychlorinated biphenyl (PCBs), Polybrominated diphenyl ethers (PBDE) Conclusion: Daily intake of dioxins and PCBs substantially exceeded the tolerable daily intake recommended by WHO. Estimated daily infant intakes of TEQPCDDs/Fs, TEQdl-PCBs (pg/kg b.w.) and PBDEs (ng/kg b.w.) in four Slovak areas. Identification and determination of trinitrotoluenes and their degradation products using liquid chromatography–electrospray ionization mass spectrometry (J. Becanová et al. / International Journal of Mass Spectrometry ˇ 291 (2010) 133–139) Method: 1. LC-MS and LC-UV Optimization of LC-MS: pH mobile phase Capillary voltage Fragmentor voltage Collision energy Profiles of illicit drug use during annual key holiday and control periods in Australia: wastewater analysis in an urban, a semi-rural and a vacation area Yin Lai et al., Addiction, 2012, 108, 556–565 Method: Waste water Filtration SPE Evaporation LC-MS/MS Conclusion: detecting changes in use of drugs Case study Determination of Clenbuterol in surface water Workflow ? Compounds class Chemical properties Sampling Sample clean-up and extraction Chemical analysis http://www.chemspider.com/Chemical-Structure.2681.html Mw 277 Log Octanol-Water Partition Coef (SRC): Log Kow (KOWWIN v1.67 estimate) = 2.00 Boiling Pt, Melting Pt, Vapor Pressure Estimations (MPBPWIN v1.42): Boiling Pt (deg C): 378.89 (Adapted Stein & Brown method) Melting Pt (deg C): 138.02 (Mean or Weighted MP) VP(mm Hg,25 deg C): 5.56E-008 (Modified Grain method) Subcooled liquid VP: 7.66E-007 mm Hg (25 deg C, Mod-Grain method) Water Solubility Estimate from Log Kow (WSKOW v1.41): Water Solubility at 25 deg C (mg/L): 3320 log Kow used: 2.00 (estimated) no-melting pt equation used Water Sol Estimate from Fragments: Wat Sol (v1.01 est) = 46916 mg/L Sacher et al., Journal of Chromatography A, 938 (2001) 199–210 1 L water SPE LC-MS/MS