LEAD IN DU ST W IPES: M ETH OD 9105, Issue 1, dated 1 5 Ma rch 2003 - Page 2 of 3 REAGENTS:
EQUIPMENT:
1.
1. Plastic pump spray bottles (fine spray preferred) with a capacity of at least 125 mL. 2. W ipes for sample collection, meeting the spe cifications o f AS TM E17 92 [1]. 3. Safety glasses or goggles. 4. Gloves, vinyl disposable or powderless latex gloves. 5. Scintillation vials, plastic screw top con tainers or plastic centrifuge tubes.
2.
3.
Vinegar (e.g., 5% ace tic acid as w hite vineg ar) or 1% nitric acid (v/v).* So dium or p ota ss ium rho dizo nate s alt (rhodizonic acid). NOT E: Rhodizonate solutions may degrade quickly over time. Solutions should be prepared fresh daily and kept refrigerated. Distilled or deionized water.
NOTE:
Com mercial kits are available.
- See SPECIAL PRECAUTIONS
SPE CIAL PR ECAU TIO NS: If 1% nitric acid is used, use common sense safety precautions when handling the solution (e.g., wear vinyl gloves, safety glasses/goggles, and avoid contact with clothing and exp osed sk in).
SAMPLING: Dermal surfaces (e.g., hands): 1. For workplace dermal sampling, tear open a wipe packet and without touching the wipe, offer the wipe to the employee to be evaluated. 2. Instru ct the em ployee to rem ove the wipe fro m the pack et, and un fold it. 3. Instruct the person to wipe the palms first, then the top surfaces of both sides of his or her hands (using normal hand washing pres sure). Tell the em ployee to wipe using the same side of the wipe, and to continue wiping his/her hands for a period of not less than 30 seconds. Other (non-dermal) surfaces: 4. Obtain wipe samples in accordance with ASTM E1728 [6], or use the following modification. a. W ith gloved hands, open a wipe packet and unfold the wipe. b. W ipe a delineated (known) area of the surface, being sure to cover the entire area thoroug hly. W ipe across the surface using repeated horizontal motions. c. Then wipe the same surface again using the same side of the wipe for sam pling, and w ipe at a right angle to the first wiping motion. d. Don a new pair of clean gloves for successive wipe samples.
SAMPLE PREPARATION: NOTE: The following procedure is written for sodium rhodizonate, and can be amend ed us ing potassium rhod izonate. Also , com m ercial spot test k its may be used to test for lead on wipe samples in lieu of the procedure described below, but sk in contac t with the rea gents should be avoided. 5. Prepare a solution of rhod izonic acid us ing the sod ium rhod izonate powder. Dissolve a pre-weighed portion of 0.135 grams (135 mg) in 105 cc of very cold water (~2 oC). This is the indicator solution. The indicator solution should turn an orange color when mixed. 6. Place a quantity of the indicator solution into one of the spray bottles, label the bottle: #2 or lead indicator solution. Refrigerate the remaining solution. 7. Fill another spray bottle with household vinegar or mak e up a 1% (v/v) nitric acid solution, label that bottle #1 or lead extraction solution. NOTE 1: The indicator solution will remain active for 2-3 days (if kept cold). After a time the indicator solution will begin to turn color (pale yellow) and lose viability, at which time a new solution NIOSH Manual of Analytical Methods (NMAM), Fourth Edition
