Methods for the Detection of Soluble Salts

1. Methods for the Detection of Soluble Salts William D. Corbett KTA-Tator, Inc.

2. Introduction • Webinar Content: • Overview and Purpose of SSPC Guide 15 • Listing of ISO Standards for Soluble Salt Detection • Methods of Surface Extraction • Methods of Analysis in the Shop or Field • Conversions Based on Assumption of Sodium Chloride • Webinar will not include: • Comprehensive step-by-step instructions • Procedures for the Boiling Extraction Method • Discussions regarding sampling location and frequency • Discussions regarding “acceptable” levels of surface chloride and/or conductivity

3. Learning Objectives/Outcomes • Completion of this webinar will enable the participant to: • Describe the purpose of SSPC Guide 15 • List the ISO Standards for soluble salt detection • Describe the difference between extraction and analysis • Describe six methods of surface extraction • Describe seven methods of analysis of extracted samples • Calculate surface concentrations based on sample concentration, sample volume and extraction area • Convert conductivity to surface concentration based on an assumption of sodium chloride

4. Purpose of SSPC Guide 15 • SSPC Technology Guide 15, “Field Methods for Retrieval and Analysis of Soluble Salts on Steel and Other Nonporous Surfaces” • Latest edition is June 1, 2005 (over 5 years old) • Scope: Common field methods for retrieval and analysis of soluble salts • Guide’s intent is to assist the user in selecting procedures for retrieval and analysis (via advantages & limitations) of soluble salts. No acceptance levels are included. • Acceptance levels are determined by the specifier

5. ISO Standards • ISO 8502, “Preparation of steel substrates before application of paints and related products – Tests for the assessment of surface cleanliness.” • Part 2: Laboratory determination of chloride on cleaned surfaces (1992) • Part 5: Measurement of chloride on steel surfaces prepared for painting – ion detection tube method (1998) • Parts 6, 9, 10 and 12 on next slide

6. ISO Standards, continued • Part 6: extraction of soluble contaminants for analysis – The Bresle method (1995) • Part 9: Field Method for conductimetric determination of water-soluble salts (1998) • Part 10: Field method for the titrimetric determination of water-soluble chloride (1999) • Part 12: Field method for the titrimetric determination of water-soluble ferrous ions (2003)

7. Draft ASTM Standard • Draft 9 of Work Item 3049, “Standard Test Methods for Assessing the Concentration of Soluble Chlorides on Abrasive Blast Cleaned Metallic Surfaces” • Repeatability study scheduled for December 2010 • Goal: Publish standard in 2011

8. Extraction versus Analysis • Two basic steps to determining soluble salt contamination: • Surface Extraction: The sampling of a known area for the purpose of determining the level of contamination • Analysis: The testing of the extracted sample for specific anions or conductivity

9. Methods of Extraction • Webinar will describe: • Swabbing • Latex Sleeve • Latex Cell • Saturated Contact Pad • Magnetic Cell • Filter Paper Saturation Notes: Other methods may exist but are not included Some proprietary information/images used

10. Methods of Analysis • Webinar will describe the use of: • Chloride ion test strips • Chloride ion detection tubes • Drop titration • Ferrous ion test strips • Nitrate ion test strips • Sulfate ion meter • Conductivity meters (non-ion specific) Notes: Other methods may exist but are not included Some proprietary information/images used

11. Extraction-Analysis Methods Compatibility Chart

12. Surface Swabbing Procedure • Pre-packaged Test Kit • Demineralizer • Graduated cylinder • Two plastic beakers • Plastic ruler • Cotton balls • Tweezers • Chloride indicator strips • Ferrous ion indicator strips • pH paper

13. Surface Swabbing Procedure • Measure a known area on the surface to be tested (e.g., 15 cm x 15 cm, or 225 cm2) • Pour a measured volume of distilled or deionized water into a plastic beaker (e.g., 22.5 mL). Water may be purchased or demineralized on site

14. Surface Swabbing Procedure 3. Dampen a sterile cotton ball in the beaker of water and swab the measured area. Be certain to use tweezers or a chloride-free latex glove. Avoid drips from vertical surfaces. 4. Swirl the cotton ball in the beaker of water, then wring cotton against beaker wall. 5. Repeat the swabbing and rinsing procedure four more times. Use a new cotton ball each time.

15. Surface Swabbing Procedure • Dry the area using a clean cotton ball. Place all cotton balls in the beaker • Stir the cotton balls in the water for 2 minutes, then wring all and measure the final volume • Obtain a control sample using the same procedures, (eliminating surface swabbing). Cover & sit for 3 minutes

16. Analysis of Swabbing Extraction • Chloride Ion Test Strips • Ferrous Ion Test Strips • Alternative Methods (described later) • Conductivity • Chloride ion detection tubes

17. Analysis of Swabbing Extraction - Chloride Ion • Remove test strip from bottle • Immerse bottom of test strip in extraction solution • Solution wicks-up center orange column • Yellow string at top turns black when analysis is complete

18. Analysis of Swabbing Extraction - Chloride Ion • Peak of the white coloration in the center orange column indicates “Quantab Unit” • Convert Quantab Unit to PPM using conversion chart on bottle • Record batch no. from bottle

19. Calculating Surface Concentrations-Chloride (swab)

20. Ferrous Ion Analysis • Remove strip from bottle • Dip strip in sample • Remove strip • Compare color to chart and record mg/L (PPM) • Convert PPM to µg/cm2 (PPM x mL of water)÷ area sampled

21. Latex Sleeve Procedure • Pre-packaged Test Kit • Five latex sleeves • Five pre-measured bottles of extraction liquid • Five chloride ion detection tubes • Tube breaker • Aspirator bulb • Instructions

22. Latex Sleeve Procedure • Pour entire contents of the premeasured extraction solution into the sleeve • Remove the pressure sensitive backing from the sleeve adhesive ring • Remove most of the air, then attach the sleeve to the surface

23. Latex Sleeve Procedure • Lift and hold the free end of the sleeve upright to allow the extraction solution to contact the surface • Use the other hand to massage the solution through the sleeve against the surface for a minimum of 2 minutes • Return the liquid into the sleeve and remove the sleeve from the surface

24. Analysis of Latex Sleeve Extraction • Chloride ion detection tube only • Pre-packaged kit • Chloride ion detection tubes • Nitrate ion detection strips • Sulfate ion detection meter • Alternative Methods (described earlier) • Chloride Ion Test Strips • Ferrous Ion Test Strips

25. Chloride Ion Detection Tube Analysis • Snap off both ends of the detection tube using the metal tube breaker • Immerse the end of the tube into the sleeve containing the extracted solution. The direction of travel is indicated by the arrow (upwards) • Use the aspirator bulb to assist with the tube saturation process as necessary

26. Chloride Ion Detection Tube Analysis • Capillary action of the tube is complete when the white cotton fibers at the top of the tube turn amber • The “pink” silver dichromate will precipitate white (silver chloride) in the presence of chloride • The pink/white intersection indicates PPM chloride (read from gradation on tube), as indicated by the red arrow • Typical range of measurement is 0+ to 60 PPM

27. Chloride, Nitrate & Sulfate Analysis • Pre-packaged Test Kit • Five extraction kits • Five chloride ion detection tubes • Five nitrate ion test strips • Five autovial filters and cone funnels • Five glass sample bottles • Five sulfate reagents (0.1g Barium Chloride) • One colorimeter for sulfate detection

28. Nitrate Analysis • Remove the test strip from the protective packaging • Immerse the “pillow end” into the solution for 2 seconds. • After 1 minute, compare color on the pillow to the color chart provided

29. Sulfate Analysis • Remove the plunger from the autovial filter assembly. Pour extracted sample through the paper funnel into the filter • Replace the plunger and position the filter onto the empty extract bottle. • Depress the plunger and filter the solution • A minimum of 7 mL is required

30. Sulfate Analysis • Recap the bottle and remove fingerprints using the cloth • Insert the bottle into the colorimeter with the vertical index line on the bottle lined-up with the point of the triangle embossed on the meter • Close the lid and depress the “zero” until “bLA” is displayed

31. Sulfate Analysis • Remove the sample container from the meter and pour the contents of one of the sulfate reagent bottles into the solution • Cap the sample container and shake for 10 seconds. remove fingerprints using the cloth provided 10. Insert the bottle into the colorimeter (as described earlier) Close the lid and depress the “Read” button.

32. Sulfate Analysis 11. Re-insert the bottle into the colorimeter with the vertical index line on the bottle lined-up with the point of the triangle embossed on the meter 12. Close the lid and depress the “Read” button. The meter will display the sulfate concentration in PPM

33. Converting PPM to Surface Concentration (Latex Sleeve Method) • Opening of latex sleeve is 10 cm2 • Premeasured extraction solution is 10 mL • Since area extracted and volume of test solution cancel out, there is no conversion required (shown below)

34. Latex Patch/Cell Procedure • Adhesive patch/cell covered with a latex film forms a cavity once attached • Patch/cell is injected with an extraction solution using a hypodermic needle • Extracted solution is tested for anions or conductivity Patch: 12.25 cm2 Cell: 12.5 cm2

35. Latex Patch/Cell Procedure • The label and foam cut-out is removed from the patch/cell • The latex patch/cell is attached to the surface • The air is extracted from the latex patch/cell using the 5 mL syringe 1 2 3 2 3

36. Latex Patch/Cell Procedure • An extraction liquid or demineralized water is used for the extraction • A known quantity of either is drawn into the 5 mL syringe (typically 2.5-3 mL) Note: Procedure may require use of extraction liquid

37. Latex Patch/Cell Procedure • The extraction liquid is injected into the latex patch/cell • The solution is massaged inside the patch/cell for 10-15 seconds • Withdraw/re-inject/ massage a minimum of 3 more times • Withdraw and dispense sample for analysis

38. Latex Patch/Cell:Methods of Analysis • Chloride ion detection strips (described earlier) • Chloride ion detection tubes (described earlier) • Ferrous ion strips (described earlier) • Drop Titration • Conductivity

39. Latex Patch/Cell:Methods of Analysis • Drop Titration Kit Includes: • 50 latex cells • Extraction fluid & waste collection bottle • Clear analysis vial • Syringes • Drop titration analysis kit • Instructions

40. Latex Patch/Cell:Methods of Analysis • Drop Titration • Kit contains 4 dropper bottles • Bottle 4 is a 5:1 dilution of Bottle 3 • Procedure: • Bottle 1: add 2 drops; swirl • Bottle 2: add 2 drops; swirl (sample turns yellow)

41. Latex Patch/Cell:Methods of Analysis • Drop Titration, con’t. • Anticipate high chloride levels: Select Bottle 3 • Anticipate low chloride levels: Select Bottle 4 • Add single drops of selected bottle until sample turns blue • Record Bottle used & no. of drops added

42. Latex Patch/Cell:Methods of Analysis Note: 1 µg/cm2 = 10 mg/m2

43. Latex Patch/Cell:Methods of Analysis Conductivity Meter • Verify accuracy of conductivity meter • Measure conductivity of “blank” • Measure conductivity of sample • Deduct conductivity reading of “blank” from conductivity reading of sample

44. Direct Sampling and Analysis • Direct Sampling Kit • Digital conductivity meter • 25 latex patches • 6 beakers • 200 mL distilled water • 20 mL syringe

45. Direct Sampling and Analysis • Direct Sampling Procedure • Measure conductivity of supplied distilled water (“blank”) • Extract sample using latex patch (previously described) • Measure conductivity of extracted sample • Deduct “blank” from conductivity value

46. Contact Pad Saturation: Extraction and Analysis • SaltSmart™ • Extraction using pre-measured de-ionized water ampoule connected to sampling device • Analysis using conductivity meter

48. Soluble Salt Meter (SSM) Extraction and Analysis • Attach SSM to surface (magnetic) • Inject de-ionized water into measurement chamber (via 3 mL fixed volume dispenser) • Meter agitates solution • Value is displayed and stored • Wipe surface and flush meter

49. Soluble Salinity Meter (SSM) Extraction and Analysis • Attach measurement cell to the surface (magnetic) • Inject 10 mL of de-ionized water using syringe. Press start key on meter • Activate the solution stirrer bar • Measurement is displayed and stored • Wipe surface and flush cell

50. Concentric Ring Conductivity Meter • Extraction using saturated filter paper; Analysis using conductivity • Saturate filter paper disc with 1.6 mL de-ionized water • Place saturated paper onto surface; push paper into surface texture using tweezers • Prepare salt contamination meter • Remove paper and position onto central area of the meter • Close lid, activate meter and read value from the display (µg/cm2)