ANALYSIS AND SCREENING OF PLASTICS FOR HEAVY METALS WITH PORTABLE XRF ANALYZER

1. ANALYSIS AND SCREENING OF PLASTICS FOR HEAVY METALS WITH PORTABLE XRF ANALYZER Stan Piorek NITON LLC NITON 2004 Asia Sales Meeting, March 30 – April 1 Langkawi, Malaysia

2. Outline • Genesis of application, regulatory issues • Why XRF? • Analytical Challenges • Analytical Approach, how we do it? • Performance • “Point-and-shoot” Approach, Measurement Requirements • Life cycle of plastics – Opportunities for XLt • Examples • New improvements in making

3. Genesis of application • Increased awareness of negative health effects of cadmium and other heavy metals in plastics prompts legislative action within the countries of the European Union. • The EC Directive 94/62/EC, Article 11, states that the sum of Cr(VI), Hg, Pb, and Cd in packaging materials may not be more than 100 [mg/kg] • The EC Directive 91/338/EC, sets the value of 100 [mg/kg] as the maximum allowable concentration of cadmium in consumer goods.

4. Genesis of application - 2 • European Parliament and Council Directive 2002/95/EC of 27 January 2003 on the restriction of the use of certain hazardous substances in electrical and electronic equipment (The so called RoHS Directive). • Targets maximum levels of Cr+6, Hg, Cd, Pb, PBB and PBDE • European Parliament and Council Directive 2002/96/EC of 27 January 2003 on waste electrical and electronic equipment (The so called WEEE Directive). • Targets responsible recycling of electronic equipment

5. Why XRF ? • Mandatory analytes and their concentrations are well suited for XRF analysis • The natural features of XRF allow for the most efficient and economical routine, fast, and reliable analysis of plastics for compliance: • Performance sufficient for the task • Nondestructive • Wide dynamic range • Simultaneously multielemental • Rugged • Fast, provides immediate results on the spot • Little or no sample preparation • “standardless” calibration • Easy to operate

6. Analytical Challenges • Relatively complex composition (elemental makeup) • Very diversified morphology (shape, size, surface finish…) • Often, extremely non-homogeneous objects • Extremely wide range of concentrations (0.0005 to 100 %)

7. Analytical Challenges - 2 Elements typically present in plastics Green: matrix elements Red: regulated elements Total: @ 25 elements that need to be monitored in order to assure correct results for regulated elements

8. Analytical Challenges – 3 Diverse Morphology of Objects Analytical technique must account for wide range of sizes, shapes, thicknesses

9. Analytical Challenges - 4 Non-homogeneity of objects How to make sure that we measure what we intend to, and that the results are representative

10. Analytical Challenges – 5 Wide range of concentrations • Matrix elements present at very high ( tens of percent) concentrations, such as: C, O, H, N and additionally Cl (in PVC’s) • Additive elements present at high concentrations, such as : Ti, Br, Sb, Sn, also Pb and Cd • Additive elements present at low (typically less than 1% level concentrations), such as: Pb, Cd, Cr, Hg

11. Analytical Approach – How we do it • What are “plastics” from the point of view of XRF analyst • What are instrumental parameters to ensure the best performance of analysis for Cr, Hg, Cd, Pb and Br • What calibration method to use • Do we need to worry about varying sample thickness

12. Analytical Approach – 2What are “plastics” ? • ABS, PTFE, HDPE, LDPE, PET, PS, PVC, …. … These are all polymers composed of C, O, H, N, and Cl. • Presence of Chlorine in PVCs drastically modifies x-ray absorption/enhancement properties of material • So, from the x-ray spectroscopist point of view “plastics” are either: PVC-based (that is all PVC), or non PVC-based, that is all polymers listed above except for PVC

13. Analytical Approach – 2 What are “plastics” ?

14. Analytical Approach - 3Instrumental parameters Ag-anode, Mo filter 38 kV, 10 – 20 uA

15. Analytical Approach – 4Calibration: Compton Norm. or FP ?

16. Analytical Approach – 5Sample Thickness

17. Current Performance for Ag-tubesPrecision and MDLs for 200 sec

18. Place probe against sample Read the result ! 3 1 Reading 302 NomSec 21.3 Non-PVC Plastic ppm err Cd 421.2 59.7 Pb 1209.3 78.9 Bal 996.5K 1.1K 2 Pull the trigger Measurement Procedure“Point and Shoot” What can be simpler?

19. Measurement Requirements Sample: - solid:- preferably flat, fully covering probe aperture, at least 4-5 mm thick. Powder, granules, pellets, small chips: - transfer to x-ray sample cup and measure in sample stand. Fill the cup to at least 10 mm depth. Alternatively, if material is available in bulk (such as drum full of pellets, etc.) one can press the probe against material and perform measurement. - large chips, stack them so they make a pile of at least 4-5 mm thick and cover probe aperture. - cable and wire insulation, strip it off the copper core and transfer to x-ray cup for measurement. Sometimes, thick, power cords with copper core may be measured directly, as often the thickness of PVC insulation is sufficient to attenuate Cu x-rays. However, this will not apply to cables with silver or tin containing core.

20. Measurement Requirements Measurement Time: Absolute minimum measurement time should not be less than 60 sec. It is not possible to make statistically meaningful measurement below 200 mg/kg concentration of Cd or Pb in shorter than 100 sec measurement time. When testing for presence of bromine, measurement time may be as short as just a few seconds. This is due to the fact that brominated flame retardans usually contain large amount of bromine.

21. Measurement Requirements Check Sample(s) or Standard(s): It is imperative to have a means of verification of the daily performance of instrument. This is best done by measuring periodically always the same, well characterized sample(s) and always under the same measuring conditions. Do not trust so called “analyzed” samples of the customer. They are often wrong as is shown on the next slide.

22. Measurement Requirements Traps to be aware of

23. Measurement Requirements Sources of Standard(CRM) and Standard Samples: CRMs exist only for non-PVC matrix. These are BCR-680 and BCR-681 standards in form of granules. They are each certified for Hg, Br, Cr, Pb, As, and Cd. The other four granulate CRMs are VDA-001 through VDA-004, and are certified for Cd only. (Certificate VDA Reference Material No 001 through 004, Institute for Reference Materials and Measurements (IRMM), Geel, June 1993. Certified Reference Materials BCR-680, and BCR-681, Trace Elements in Polyethylene, European Commission, Community Bureau of Reference – BCR, Brussels, January 2000.) No CRMs are available in PVC nmatrix. Standard Samples are available from third party sources.

24. Life Cycle of Plastics: Opportunities for XLt Manufacture of product or component from granulate Consumer, final user Compounding polymer and additives into granulate Recycling: collection, separation and sorting Manufacture of virgin polymer resin from crude Regrinding WASTE REFINERY OIL WELL LANDFILL or INCINERATOR

25. Standard RoHS Test Procedure PBB/PBDE Br > 750 ppm Method:IR, HPLC Representative Sample e.g. Printed Wiring AssemblyHousingDisplay Field Replaceable Units(expressed in weight % of that sample) Method: EPA 3060AEPA 7196A Diphenylcarbazide Cr > 750 ppm Cr VI ScreeningMethod:DesktopEDXRF Hg > 750 ppm Hg Method: AAS Method: ED-XRF, ICP-AES Pb Pb > 750 ppm KEY IR = Infrared Spectroscopy HPLC = High Performance Liquid Chromatography AAS = Atomic Absorption Spectroscopy EDXRF – X-Ray Florescence Spectroscopy ICP-AES = Inductive Coupled Plasma – Atomic Emission Spectroscopy Br, Cr, Hg, Pb < 750 ppm Cd < 75 ppm Cd Cd > 75 ppm Method: ED-XRF, ICP-AES RoHS Compliant *Chart created by Markus Stutz and Michael Riess, Motorola. and slightly modified by USITO This slide borrowed from Motorola’s Presentation

26. Standard Testing Method Content: Details Shaded row: Most important testing standard This slide borrowed from Motorola’s Presentation

27. Life Cycle of Plastics: Opportunities for XLt - 2 • Incoming inspection of compounded plastics (such as granulate) • Incoming inspection of components and subassemblies such as cables, wires, enclosures. • Screening of plastics for presence of brominated flame retardants and any other major elements such as Sb, Sn, etc. • Quantitative analysis of metals in plastics.

28. Life Cycle of Plastics: Opportunities for XLt - 3 • Screening of printed circuit boards for presence of brominated flame retardants; edge-on measurement to avoid picking up of other elements • Quantitative analysis of metals in plastic toys and objects of common use (binders, etc.)

29. Life Cycle of Plastics: Opportunities for XLt - 4Screening for BrFR Screening: analysis with relaxed accuracy and/or precision requirements By just comparing spectra of these samples, the instrument can sort them into various Br levels categories, in a matter of 2 to 5 sec of measurement time per sample. Spectrum of BCR-680 standard is included for comparison

30. Examples The next few slides show examples of samples and results of measurements obtained on them with XLt 794

31. Metallic Contaminants in Plastics - 1 Lead content is about 1200 {mg/kg]

32. Metallic Contaminants in Plastics - 2 Lead content is about 900 [mg/kg]

33. Metallic Contaminants in Plastics - 3 Lead is in yellow painted sections

34. Metallic Contaminants in Plastics - 4 Sn = 135 Zn = 167 Ti = 3.3% Br = 265 Cd = 35 Pb = 50 Ti = 1.8% Sn = 2300 Fe = 620 Zn = 4750 Ti = 0.42% Sn = 88 Pb = 235 Zn = 57 Ti = 4% Br = 46

35. Metallic Contaminants in Plastics - 5 Pb = 80+/-15 Zn = 200+/-40 Ti = 1.4+/-.14% PVC matrix

36. Metallic Contaminants in Plastics - 6 Lead is present at 8600 [mg/kg] level in these PVC pellets

37. Metallic Contaminants in Plastics - 7 Lead is present at 2600 [mg/kg] level in this binder. Cd is present at 180 [mg/kg]

38. Metallic Contaminants in Plastics - 8 By measuring this PC board edge-on, Br presence was identified within the first second of the measurement, and no interference from other objects nor from copper in the board was observed

39. Future Improvements – filters for better Cr MDL

40. Future Improvements – tube spot quality Then Now

41. Future Improvements – New Tube(s) Moxtek Arpes New Niton Svetlana