Methods for the Detection of
Soluble Salts
William D. Corbett
KTA-Tator, Inc.
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
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
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
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
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)
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
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
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
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
Extraction-Analysis Methods
Compatibility Chart
Methods of Surface Extraction
E1: Surface Swabbing
Methods of Analysis
A1: Chloride Ion Test Strip
A2: Drop Titration
A3: Chloride Ion Detection Tube
A4: Probe-Type Conductivity Meter
E2: Adhesively Bonded Patch Cell A1: Chloride Ion Test Strip
A2: Drop Titration
A3: Chloride Ion Detection Tube
A4: Probe-Type Conductivity Meter
E3: Adhesively Bonded Sleeve
A1: Chloride Ion Test Strip
A2: Drop Titration
A3: Chloride Ion Detection Tube
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
Surface Swabbing Procedure
1. Measure a known
area on the surface to
be tested (e.g., 15 cm
x 15 cm, or 225 cm2)
2. 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
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 chloridefree 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.
Surface Swabbing Procedure
6. Dry the area using a clean
cotton ball. Place all cotton
balls in the beaker
7. Stir the cotton balls in the
water for 2 minutes, then wring
all and measure the final
volume
8. Obtain a control sample using
the same procedures,
(eliminating surface swabbing).
Cover & sit for 3 minutes
Analysis of Swabbing Extraction
• Chloride Ion Test Strips
• Ferrous Ion Test Strips
• Alternative Methods (described later)
Conductivity
Chloride ion detection tubes
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
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
Calculating Surface
Concentrations-Chloride (swab)
Entry
Result
PPM (from chart)
124 PPM
Quantity of water
22.5 mL
PPM x Quantity of Water
124 x 22.5 = 2790 µg
Area sampled
225 cm2
Micrograms ÷ Area Sampled 2790÷225 =12.4 µg/ cm2
Ferrous Ion Analysis
1.
Remove strip from
bottle
2. Dip strip in sample
3. Remove strip
4. Compare color to
chart and record
mg/L (PPM)
5. Convert PPM to
µg/cm2 (PPM x mL of
water)÷ area
sampled
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
Latex Sleeve Procedure
1.
Pour entire contents
of the premeasured
extraction solution
into the sleeve
2. Remove the pressure
sensitive backing from
the sleeve adhesive
ring
3. Remove most of the
air, then attach the
sleeve to the surface
Latex Sleeve Procedure
4. Lift and hold the free end
of the sleeve upright to
allow the extraction
solution to contact the
surface
5. Use the other hand to
massage the solution
through the sleeve
against the surface for a
minimum of 2 minutes
6. Return the liquid into the
sleeve and remove the
sleeve from the surface
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
Chloride Ion Detection Tube
Analysis
1.
Snap off both ends of the
detection tube using the
metal tube breaker
2. Immerse the end of the
tube into the sleeve
containing the extracted
solution. The direction
of travel is indicated by
the arrow (upwards)
3. Use the aspirator bulb to
assist with the tube
saturation process as
necessary
Chloride Ion Detection Tube
Analysis
1.
Capillary action of the tube is
complete when the white cotton
fibers at the top of the tube turn
amber
2. The “pink” silver dichromate will
precipitate white (silver chloride)
in the presence of chloride
3. The pink/white intersection
indicates PPM chloride (read from
gradation on tube), as indicated by
the red arrow
4. Typical range of measurement is
0+ to 60 PPM
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
Nitrate Analysis
1. Remove the test strip
from the protective
packaging
2. Immerse the “pillow
end” into the solution
for 2 seconds.
3. After 1 minute,
compare color on the
pillow to the color
chart provided
Sulfate Analysis
1.
Remove the plunger
from the autovial filter
assembly. Pour extracted
sample through the
paper funnel into the
filter
2. Replace the plunger and
position the filter onto
the empty extract bottle.
3. Depress the plunger and
filter the solution
4. A minimum of 7 mL is
required
Sulfate Analysis
5. Recap the bottle and
remove fingerprints
using the cloth
6. 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
7. Close the lid and depress
the “zero” until “bLA” is
displayed
Sulfate Analysis
8. Remove the sample
container from the meter
and pour the contents of
one of the sulfate reagent
bottles into the solution
9. 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.
Sulfate Analysis
11. Re-insert the bottle into the
colorimeter with the vertical
index line on the bottle linedup 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
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)
Entry
Result
PPM
25 PPM
PPM x mL of Solution
25 x 10 = 250 micrograms
Area Extracted
10 cm2
Micrograms ÷ Area
25 micrograms/cm2
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
Latex Patch/Cell Procedure
1. The label and foam
cut-out is removed
from the patch/cell
2. The latex patch/cell
is attached to the
surface
3. The air is extracted
from the latex
patch/cell using the 5
mL syringe
1
2
3
2
3
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 2.53 mL)
Note: Procedure may require
use of extraction liquid
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
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
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
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)
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
Latex Patch/Cell:
Methods of Analysis
No. of Drops – Bottle 3
Concentration of Chloride Ion
1
Less than 10 µg/cm2
2
10 - 20 µg/cm2
3
20 - 30 µg/cm2
4
30 - 40 µg/cm2
No. of Drops – Bottle 4
Concentration of Chloride Ion
1
Less than 2 µg/cm2
2
2 - 4 µg/cm2
3
4 - 6 µg/cm2
4
8 - 10 µg/cm2
Note: 1 µg/cm2 = 10 mg/m2
Latex Patch/Cell:
Methods of Analysis
Conductivity Meter
1.
Verify accuracy of
conductivity meter
2. Measure conductivity of
“blank”
3. Measure conductivity of
sample
4. Deduct conductivity
reading of “blank” from
conductivity reading of
sample
Direct Sampling and Analysis
• Direct Sampling Kit
 Digital conductivity
meter
 25 latex patches
 6 beakers
 200 mL distilled water
 20 mL syringe
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
Contact Pad Saturation:
Extraction and Analysis
• SaltSmart™
 Extraction using premeasured de-ionized
water ampoule
connected to sampling
device
 Analysis using
conductivity meter
47
Soluble Salt Meter (SSM)
Extraction and Analysis
A. Attach SSM to surface
(magnetic)
B. Inject de-ionized water
into measurement
chamber (via 3 mL fixed
volume dispenser)
C. Meter agitates solution
D. Value is displayed and
stored
E. Wipe surface and flush
meter
Soluble Salinity Meter (SSM)
Extraction and Analysis
1.
2.
3.
4.
5.
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
Concentric Ring Conductivity
Meter
• Extraction using saturated
filter paper; Analysis using
conductivity
1.
2.
3.
4.
5.
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)
Converting Conductivity to
Surface Concentration
•
•
•
•
Appendix C.1 in SSPC Guide 15
Estimate of surface concentration
Assumption is sodium chloride
E = 0.3 x S x (V÷A)
 E: Surface concentration (μg/cm2)
 S: Conductivity (μS/cm)
 V: Volume of extraction solution used
 A: Area of sample collection
Summary
• During this webinar, we have:
 Described the purpose of SSPC Guide 15
 Listed the ISO Standards for soluble salt detection
 Described the difference between extraction and analysis
 Described six methods of surface extraction
 Described seven methods of analysis of extracted samples
 Calculated surface concentrations based on sample
concentration, sample volume and extraction area
 Converted conductivity to surface concentration based on an
assumption of sodium chloride
Methods for the Detection
of Soluble Salts
THE END