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Low Level Mercury by Thermo-decomposition of Fish and Soil using Hydra II-C Analyzer

By: Jack Hall, Quality Assurance Manager Materials and Chemistry Laboratory, Inc. ( McLinc ). Low Level Mercury by Thermo-decomposition of Fish and Soil using Hydra II-C Analyzer. T he ASP 2013 A nnual W orkshop. S tudy G oal :

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Low Level Mercury by Thermo-decomposition of Fish and Soil using Hydra II-C Analyzer

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  1. By: Jack Hall, Quality Assurance Manager Materials and Chemistry Laboratory, Inc. (McLinc) Low Level Mercury by Thermo-decomposition of Fish and Soil using Hydra II-C Analyzer The ASP 2013 Annual Workshop

  2. Study Goal: Evaluate the Precision and Accuracy of a Thermo-Decomposition Instrument on Fish and Soil. Materials and Chemistry Laboratory, Inc. (McLinc)

  3. Teledyne/Leeman Labs Hydra llc Automated Direct Hg Analyzer (Total Operation fits on a standard desk top.) Materials and Chemistry Laboratory, Inc. (McLinc)

  4. Method based on EPA Method 7473: • Mercury in Solids and Solutions by Thermal Decomposition, Amalgamation, and Atomic Absorption Spectrophotometry • Determines Total Mercury- OrganicandInorganic (CAS No. 7439-97-6) in the following matrices: • Soils • Sediments • Bottom Deposits • Sludge-type Materials • Aqueous Wastes • Ground Water, and • Digested Solutions. Materials and Chemistry Laboratory, Inc. (McLinc)

  5. Process Description: • Drying & Combusting (decomposition) of a sample at high temperatures with oxygen producing gases. • Gases are carried through a heated catalyst that removes: • halogens, • nitrogen oxides, and • sulfur oxides. • (continued on next slide) Materials and Chemistry Laboratory, Inc. (McLinc)

  6. ProcessDescription (continued): • Remaining combustion products (including elemental mercury) are swept through a gold amalgamation tube. • Amalgamation tube captures all of the mercury. • Amalgamation tube is then heated to release mercury as a gaseous bolus into carrier gas . • (continued on next slide) Materials and Chemistry Laboratory, Inc. (McLinc)

  7. Process Description (continued): • Carrier gas transports to the cold vapor atomic absorption spectrometer (CVAAS). • Transient signal measured in series by a high sensitivity cell followed by a low sensitivity cell. • Two peaks are integrated and reported against the best calibration of the two cells available. • (continued on next slide) Materials and Chemistry Laboratory, Inc. (McLinc)

  8. Process Description (continued): • Purpose of the two cells is to provide a wider dynamic range of linearity than can be provided by a single optical cell length. Materials and Chemistry Laboratory, Inc. (McLinc)

  9. Absorption Cells (1) Sample Boat High Sensitivity Low Sensitivity Air 50 to 900C 600C (4) Drying Tube (5) Amalgam Trap (6) Spectrometer (2) Decomposition Furnace (3) Catalyst Furnace O2 Supply Principal of Operation Materials and Chemistry Laboratory, Inc. (McLinc)

  10. Autosampler Rack Materials and Chemistry Laboratory, Inc. (McLinc)

  11. Sample Boat for Autosampler Materials and Chemistry Laboratory, Inc. (McLinc)

  12. Blank Soil SRM 2586 Soil (367±0.038ng/g) SRM 1947 Lake Michigan Fish Tissue (254±5ng/g) Materials and Chemistry Laboratory, Inc. (McLinc)

  13. Paddlefish Filet caught near Fort Loudon Dam in Tennessee Preparation of Paddlefish using a Hamilton-Beach Blender Materials and Chemistry Laboratory, Inc. (McLinc)

  14. Picture of Paddlefish and Boat Paddle Materials and Chemistry Laboratory, Inc. (McLinc)

  15. Paddlefish Sample Preparation (Sample ID: LD Fish Tissue): • Approximately a two pound filet obtained from a paddlefish, caught in the Tennessee River, in Watts Bar Lake, was prepared for mercury analysis. • Using a razor blade, the meat of the filet was removed from the skin in small chunks. [Note - no bones were present in the filet.] • Next, the meat was placed in a stainless steel blender to thoroughly homogenize and size reduce the chunks. • The meat was then transferred to a Teflon® sample bottle to await analysis. The samples made from standard materials were used as is. Preparation of Samples for Mercury Analysis Materials and Chemistry Laboratory, Inc. (McLinc)

  16. Calibration Standard Stock Standard #1 UltraScientific, Cat.# ICM-303 Lot# M00317 MCL# CV011 Hg = 100±0.5µg/mL Matrix: 5% Nitric Acid Exp. Date: 04-30-2014 Second Source NIST: SRM2586 Trace Elements in Soil Hg = 0.367±0.038µg/kg (367ng/g) LOW Range Rho = 0.9995414 HIGH Range Rho = 0.9997137 LOW Range CCV = 95%R HIGH Range CCV = 106%R Stock Standard #1, 0.1ppm Hg CV011: 0.1mL diluted to 100mL with di-water Stock Standard #2, 1.0ppm Hg CV011: 1.0mL diluted to 100mL with di-water Initial Calibration Materials and Chemistry Laboratory, Inc. (McLinc)

  17. Actual Printout of the Low Calibration Curve Materials and Chemistry Laboratory, Inc. (McLinc)

  18. Actual Printout of High Calibration Curve Materials and Chemistry Laboratory, Inc. (McLinc)

  19. Mean = 9.95 Tng StdDev = 0.236 MDL = 0.74 Lowest Std/RL, Tng = 5.0 Spiked Soil MDL Study Materials and Chemistry Laboratory, Inc. (McLinc)

  20. Mean = 56.71ng/g StdDev = 4.257 MDL = 13.38 Lowest Std/RL, Tng = 5.0 Paddlefish MDL Study (Fish Tissue) Materials and Chemistry Laboratory, Inc. (McLinc)

  21. Mean = 32.24 Tng StdDev = 2.663 MDL = 8.37 Lowest Std/RL, Tng = 5.0 • %R - Percent Recovery t=2.896 • Used 9 runs in MDL calculation: MDL – 1, 2, 4, 6, 7, 8, 9, 10, and 11. NIST: SRM 1947 Fish Tissue MDL Study Materials and Chemistry Laboratory, Inc. (McLinc)

  22. Mean = 43.18 Tng StdDev = 4.630 MDL = 14.55 Lowest Std/RL, Tng = 5.0 • %R – Percent Recovery t=2.764 • Used all 11 runs in MDL calculation. NIST: SRM 2586 Soil MDL Study Materials and Chemistry Laboratory, Inc. (McLinc)

  23. Mercury in SRM 2586 Spiked Soil vsExpected Mercury of 367±0.038ng/g(corrected for weight) Materials and Chemistry Laboratory, Inc. (McLinc)

  24. Standard SRM 2586 Mercury (Hg) Soil Analysis Using Different Weights (0.1g, 0.3g, and 0.5g) Materials and Chemistry Laboratory, Inc. (McLinc)

  25. Mercury in SRM 1947 Fish Tissue vsExpected Mercury of 254±5ng/g(corrected for weight) Materials and Chemistry Laboratory, Inc. (McLinc)

  26. LD Fish vs. SRM 2586 Spiked Soil vs. SRM 1947 Fish Tissue Materials and Chemistry Laboratory, Inc. (McLinc)

  27. Conclusions and Recommendations: • Simple preparation. • Ease of use. • Best sample size 0.1 to 0.3g. • Great Accuracy (% Recovery) of Soil at low weight. • Positive but acceptable Accuracy (Bias) of Fish Tissue. • Soil Precision very good with a CV= <0.03 • Fish Precision also good with a CV = <0.08 • Thermo Decomposition is Very Suitable for Both Matrices. Materials and Chemistry Laboratory, Inc. (McLinc)

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