Sediment Sample Digestion Method Comparative Study Prepared by Ph.D Kwon Seok .Park Marine Police R&D Center

Content Study Background And Proficiency Test (push forward content) 2. Comparative Digestion Method 3. Survey Result 4. Conclusion

I. Study Background And Objective International Analysis Efficiency Test and Analysis Ability Appraise by ISO Certification Application Found some problems in digestion Study Objective Differences between Heating Digestion and Microwave Digestion Analysis Result Appraise by Statistical Method

2. Progress ’08. 6. 30 International Approval Organization Efficiency Test 8. 1 ~ 22 Heavy Metal for Analysis Sample 8. 25 Statistical Interpretation for Analysis Result & Report 10. 24 Analysis Result from APLAC Supervision : (APLAC) Subject : (HKAS) Participate Scale : 42 Countries 109 Institutes

Process Digestion Filtering Final Sample Analysis (ICP/MS)

ICP/MS Measurement

Statistical Interpretation Result by Analysis Result Cadmium (Cd) : 0.288±0.009 mg/kg (Z-Score 0.15) Certified Value : 0.263±0.004mg/kg Lead (Pb) : 1.561±0.059 mg/kg (Z-Score 0.24) Certified Value : 1.463±0.025mg/kg 7

Z Score 0 Range Won The Best Top Grade Result Z Score 0 Range Won The Best Top Grade Participate Scale : 42Countries 109Institute 8

Comparative Digestion System

Comparative Analysis System

The Marine Police R&D Center’s Digestion Comparative Method Heating vs Microwave Heating Vessel vs Teflon Beaker

3. Study Method Sample for analysis Analyze Items Sample : Unknown Powder Sample 5 g (International Approval Organization Menufacture) Reference : RM Class Powder Sample 8 g (Korea Standard Science Researcher Menufacture) Analyze Items Cd, Pb (2ea items) Instrumental Analysis Systems Inductively Coupled Plasma Mass Spectromerty (ICP/MS) Model : Varian 830

Digestion Method The Marine Pollution Official Test Method for Sediment Digestion System : Hot Plate, Microwave Heating Microwave

Digestion Process 24 hr Stay Microwave digestion Air Cooling Massup - Conc. HNO3 10 ml 加 - 1 % HNO3 15 ml 加 - Conc. HNO3 5 ml 加 - Conc. HClO4 2.5 ml 加 Standard Stock Solution (10 ppm) Working Standard Solution (1.0 ppm) Calibration (5, 10, 20, 50 ppb) Powder Sampl 0.2 g을 Telfon Cell에 取 24 hr Stay Microwave digestion Air Cooling Massup Filtering - 220, 5hr (Slowly heating up) Put Powder Sample 0.2g into Vessel Heating Room temperature Cooling Mass-up ICP/MS Measurement - 180. 450psi, 30min

Digestion Process (Ex.Teflon Beaker) Put Sample 0.5 g into teflon beaker - Conc. HNO3 5 ml 加 - HClO4 2.5 ml 加 - HF 2.5 ml 加 Heating Standard Stock Solution (10 ppm) - 130 (Slowly heating up) ) Reheating when undigested Working Standard Solution (1.0 ppm) - Conc. HNO3 10 ml 加 - HClO4 10 ml 加 - HF 2.5 ml 加 Room temperature Cooling Calibration (5, 10, 20, 50 ppb) Mass-up Filtering ICP/MS Measurement

4. Result Accuracy Heating (Vessel) vs Microwave

The concentration changes according to temperature Heating (Vessel)

Recovery Rate Digestion Vessel : Vessel (Closed Type) and Teflon Beaker (Open Type) Digestion Method : Heating

Teflon Beaker (Open type) Digestion Vessel Vessel (Closed type) Teflon Beaker (Open type)

Digestion Vessel

5. Conclusion Comparative Digestion Methods for Cd, Pb Items Heating Method Accuracy is higher than Microwave Closed Digestion Vessel’s Recovery Rate is higher than other vessels The similar concentration is maintained over 180 ℃ Leaving the sample for natural digestion impacts on analysis result differences

Any Questions ?