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

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

3. 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

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

5. Process
Digestion
Filtering
Final Sample
Analysis (ICP/MS)

6. ICP/MS Measurement

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

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

9. Comparative Digestion System

10. Comparative Analysis System

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

12. 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

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

14. 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
psi, 30min

15. 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

16. 4. Result
Accuracy
Heating (Vessel) vs Microwave

17. The concentration changes according to temperature
Heating (Vessel)

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

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

20. Digestion Vessel

21. 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

22. Any Questions ?