Materials and Reagents:
- Nitric Acid, Trace Metal Grade
- Glass Test Tubes
- Filter Paper - 55mm diameter, No. 2 filters
- Pre-wetted Wipes (optional)
- Hot Plate
- Distilled Water
- Certified reference lead standard.
For each of 3 separate #2 filter papers of 55mm diameter, weigh the filter paper and wet it with the same weight (±10%) of distilled water, or use similar commercial pre-wetted wipes, such as Ghost™ wipe. Gently wipe each filter 10 times over a known, intact surface area on the item being tested. Wiping is done in one direction over the surface. Wipe same area each time with each wipe (10 times each with 3 wipes for a total of 30 strokes over the area). If sample is sufficiently large, use 100cm2 area; for smaller samples use less, but record area used.
Digest the filter papers individually in concentrated nitric acid at reflux conditions for 6 hours. Analyze digested samples for lead concentration by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), Flame Atomic Absorption Spectrometry (FAAS), or Graphite Furnace Atomic Absorption Spectrometry (GFAAS) Techniques following methodology found in ASTM E 1613.
The results for accessible metal wiped from the surface are summed and divided by the total number of wipes and expressed as the average micrograms per 100cm2 per wipe (µg/100cm2/wipe).
Use good laboratory practices for calibration, method blank, quality control checks, and detection limits.
*This methodology was developed by CPSC staff, has not been reviewed or approved by, and may not reflect the views of, the Commission.