Sediment Sample Digestion Method Comparative Study Prepared by

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

Content 1. Study Background And Proficiency Test (push forward content) 2. Comparative Digestion Method 3. Survey Result 4. Conclusion

I. Study Background And Objective Study Background 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 Ø Supervision : (APLAC) Ø Subject : (HKAS) Ø Participate Scale : 42 Countries 109 Institutes

Process Digestion Final Sample Filtering Analysis

ICP/MS Measurement

Statistical Interpretation Result by Analysis Result Ø Cadmium (Cd) : 0. 288± 0. 009 mg/kg (Z-Score 0. 15) ü Certified Value : 0. 263± 0. 004 mg/kg Ø Lead (Pb) : 1. 561± 0. 059 mg/kg (Z-Score 0. 24) ü Certified Value : 1. 463± 0. 025 mg/kg

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

Comparative Digestion System

Comparative Analysis System

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

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

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

Digestion Process Put Powder Sample 0. 2 g into Vessel 24 hr Stay Powder Sampl 0. 2 g을 Telfon Cell에 取 - Conc. HNO 3 10 ml 加 - 1 % HNO 3 15 ml 加 - Conc. HNO 3 5 ml 加 - Conc. HCl. O 4 2. 5 ml 加 Heating Room temperature Cooling 24 hr Stay Standard Stock Solution (10 ppm) Microwave digestion Working Standard Solution (1. 0 ppm) Air Cooling (5, 10, 20, 50 ppb) - 220, 5 hr (Slowly heating up) - 180. 450 psi, 30 min Mass-up Massup Filtering ICP/MS Measurement Calibration

Digestion Process (Ex. Teflon Beaker) Put Sample 0. 5 g into teflon beaker Heating Reheating when undigested Room temperature Cooling - Conc. HNO 3 5 ml 加 - HCl. O 4 2. 5 ml 加 - HF 2. 5 ml 加 Standard Stock Solution (10 ppm) - 130 (Slowly heating up) ) - Conc. HNO 3 10 ml 加 - HCl. O 4 10 ml 加 - HF 2. 5 ml 加 Working Standard Solution (1. 0 ppm) Calibration (5, 10, 20, 50 ppb) Mass-up Filtering ICP/MS Measurement

4. Result Accuracy Ø Heating (Vessel) vs Microwave

The concentration changes according to temperature Ø Heating (Vessel)

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

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

Digestion Vessel

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

l Any Questions ?