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Western Safety Products, Inc. 505 South Lander St., Seattle, WA 98134
Toll Free: (888) 823-0808 Phone: (206) 264-0808 Fax: (206) 264-4921
Website: http://www.westernsafety.com sales@westernsafety.com

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Lead Check

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Lead Check Introduction
Lead Check Kit

Description LeadCheck® Swabs are non-hazardous and provide a rapid, sensitive and specific test for leachable lead on any surface. When lead is detected, LeadCheck® Swabs and/or the surface being tested turns pink or red on contact, depending on the concentration of lead present. In the vast majority of test situations results are obtained in less than 30 seconds. When detecting low levels of lead, or lead chromate containing pigments, results may take longer to develop. Each kit contains test confirmation cards to verify individual test results.
Since their introduction in 1992, LeadCheck® Swabs have been used to detect lead under a wide variety of field test conditions. Recognized by industry professionals for superior accuracy and sensitivity, LeadCheck® Swabs have outperformed other screening methods in every government evaluation conducted over the past 15 years.

Sensitivity:
  • 1 ug on solid surfaces
  • 2 ppm in liquid
  • Contact us for sensitivity information on specific items.
Stability:
  • Indefinite
Interferences:
  • As provided interferences are minimized.

Lead Check

How To Activate A LeadCheck® Swab:
LeadCheck® Swabs are self–contained test units which provide a rapid, easy to use, sensitive and specific test for lead on any surface.

Each LeadCheck® Swab contains two crushable vials (see picture below). A lead reactive reagent is stored in one vial. The second vial contains pre-measured “activator’ solution to ensure proper conditions for the lead complex to form. When a swab is activated by crushing the vials and mixing the contents and the tip is brought in contact with lead, the pink (red) compound characteristic of lead forms. A confirmation card containing a small quantity of lead is included with the product to prove that the test was performed properly.

Method
To activate LeadCheck® Swabs:

Lead Check Swab
First Step CRUSH - firmly at the two points indicated, first A then B.
Second Step SHAKE AND SQUEEZE – Shake the Swab twice and squeeze gently until yellow liquid comes to the tip- the swab is now activated and ready for testing
Third Step RUB -- While continuing to squeeze to keep the yellow liquid at the tip, vigorously rub the surface to be tested.
If an unmistakable pink color forms on the tip of the swab, or on the surface being tested, lead is present at a hazardous level.
COLOR GUIDE FOR LEADCHECK® SWABS ON PAINT:
LeadCheck® Swabs detect lead on painted surfaces and on other surfaces based on a reaction between lead and the lead reactive reagent. In this interaction color development increases in proportion to increasing lead concentration. LeadCheck® Swabs is the only qualitative colorimetric lead detection product that offers the user the opportunity to estimate lead concentration on a site. When LeadCheck® Swabs are used, it is possible to suggest lead concentration ranges associated with each series of color gradations.
A series of colors developed at each concentration of lead would produce the following ranges.
High Lead Content
5.0% --------------------------------------10.0%
High Lead Concentration Range
(5.0% to 10.0% lead)
Medium Lead Content
0.5% --------------------------------------3.0%
Medium Lead Concentration Range
(0.5% to 3.0% lead)
Low Lead Content
0.0% -------------------------------------- 0.3%
Low Lead Concentration Range
(0.0% to 0.3% lead)
NOTE: 0.06% is 600 ppm; 0.1% is 1000 ppm; 0.5% is 5000 ppm, etc.
I. The Reaction
A LeadCheck® Swab contains two glass ampoules each containing the reagents required for the colorimetric detection of lead (II). One ampoule contains a lead reactive dye which under the proper conditions of pH and solvent conditions turns red. The second ampoule contains the buffers and solvents required to optimize the reaction of lead with the dye. LeadCheck® provides careful control of the ratio of solvent to dye which provides a reproducible and reliable test with an indefinite shelf-life. The reaction leads to a pink to deep red result on the tip of the swab (depending on the concentration of lead present and/or the surface being tested). The color development is linear with concentration.
II. Sensitivity
To determine the sensitivity of LeadCheck® Swabs, a standard curve was prepared with a standard paint solutions prepared by an outside laboratory. Dilutions of the standardpaint were applied to one cm square areas on plate glass. These were used to determine the standard curve. The painted squares were scraped off the glass, digested and quantitated by atomic absorption spectroscopy. The following table illustrates the reaction of LeadCheck® Swabs to each concentration of lead in paint. A clear gradation of color was observed and an arbitrary rating was assigned to each with 1.52+ indicating the 100% color saturation.

 Lead Tested (% w/w)

Color Result

Rating (%)

1.0, 0.7, 0.54

Deep red Deep red Red

100, 98, 87

0.43

Red

68

0.22

Medium red

33

0.12, 0.06, 0 (no Pb (II))

Light pinkLight pink - easily seen Colorless

20, 9, 0

These reactions were repeated five times with the same results.
III. Specificity
LeadCheck® Swabs are quite specific for lead. High levels of stannous chloride (tin) (5mg/ml) may interfere with color development; however the rate of reaction with lead is much faster than the rate of reaction with tin. High concentrations of silver may interfere with color development.
IV. Reaction with Lead Chromate Paint
LeadCheck® Swabs (PB2M) detect lead in lead chromate paint at the same levels as found for the lead nitrate standard. The reaction with lead chromate is significantly slower than other lead compounds taking as long as 30 minutes of constant contact to develop.

Third Party Documentation of the Performance of LeadCheck Swabs
1. NIST Study, May 2000. Spot Test Kits for Detecting Lead in Household Paint: A Laboratory Evaluation. (NISTIR 6398). For this study, HUD funded NIST (the National Institute of Standards and Technology) to “determine the reliability of spot test kits for detecting the presence of lead in household paint when tests were conducted by certified lead inspectors or risk assessors.” The full NIST study can be downloaded from either www.nist.gov or www.hud.gov by simply typing “NISTIR 6398” in the search window on the home page of either site.
2. FDA Laboratory Information Bulletin. Identification of Lead Solder on a Metal Can Seam (No. 4041, July, 1996, Volume 12, Number 7.) In 1995 the U.S. Food and Drug Administration (FDA) amended its food additive regulations to prohibit the use of lead solder in the manufacture of cans used for packaging foods [(1995) 60 (June 27), 33106-33109; 21 CFR 189.240)]. This FDA Laboratory Bulletin reports the development of a protocol for detecting lead alloy solder on a metal food can using a chemical spot kit.
3. MRI-Quantech Study, 1995. (A Field Test of Lead-based Paint Testing Technologies. Summary and Technical Report – EPA 747-R-95-002a&b). The data section of this huge study includes “Operating Characteristic Curves” for LeadCheck Swabs on wood and brick, for example, that prove LeadCheck’s reliability. In both of these performance curves, the probability of obtaining a positive result at the action level (1 mg/cm2) is nearly one, that is, close to ideal behavior as defined by EPA in 1993 (Identification of Performance Parameters for Test Kit Measurement of Lead in Paint (EPA600R-93/129)). Clearly, these MRI-QuanTech “operating characteristic curves” demonstrate that LeadCheck Swabs perform reliably and accurately to detect lead paint hazards. Yet in spite of the apparent good performance by LeadCheck Swabs and others, this data was overlooked when the EPA claimed that Chemical Spot Test Kits are not reliable for testing lead-based paint, a conclusion that was not supported by the data!
4. Lead Test Kits, OSHA, September 1994. This study identified LeadCheck Swabs as “capable of identifying lead at the levels given in the Lead Exposure Reduction Act (October 29, 1992) and the Department of Housing and Urban Development (HUD) Interim Guidelines (September 1990, revised May 1991)…… “With the LeadCheck tests, cutting into the paint to expose all layers will make it possible to determine if any layer has an amount of lead greater than that allowed in the HUD requirements.”
5. Evaluation of Lead Test Kits, Consumer Product Safety Commission (CPSC), September 1994. Released to manufacturers, but not to the public, this limited study identified LeadCheck Swabs as one of the top performing chemical spot test kits.
6. A Comparative Test and Evaluation of Lead-based Paint Test Kits. (Masters Thesis by Lynn Hill, Air Force Institute of Technology, 1993.) LeadCheck Swabs was the only kit tested that gave a performance curve for lead chromate paint. The inflection point was around 0.3 – 0.4% lead. A positive result was obtained nearly 100% of the time on paint that was 0.5% lead and greater.
7. Chemical Lead Paint Inspection Methodology as an Alternative to Existing Inspection Procedures (Pinto Protocol),( October 1993, Wonder Makers, Inc., Kalamazoo, MI.) During the screening of 63 homes for lead-based paint, 692 paint samples were collected and tested with LeadCheck Swabs. Of these, 301 samples were found to be positive. Quality control analysis by Laboratory AA of paint chips indicated that a few “positives” were just below 0.5% and one negative was above 0.5%. Retesting of that negative result with LeadCheck Swabs revealed an operator error: LeadCheck gave a positive result on retesting.
8. EMG Group: In 1993, the EMG Group tested 400 homes with LeadCheck Swabs and AA Laboratory tests on paint chips taken from the same sites where LeadCheck tests were performed. They found “absolutely consistent results” both positive and negative with LeadCheck Swabs and AA results.
ASTM CONSENSUS STANDARDS FOR CHEMICAL SPOT TEST KITS
Over the past several years, ASTM Subcommittee E06.23 on Lead Hazards Associated with Buildings has promulgated two consensus standards for qualitative chemical spot test kits:
E 1753 Standard Practice for the Use of Qualitative Chemical Spot Test Kits for Detection of Lead in Paint Films.
E1828 Standard Practice for Evaluating the Performance Characteristics of Qualitative Chemical Spot Test Kits for Lead in Paint.

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