Handwipe disclosing method for the presence of lead

• US 6,248,593 B1
• Filed: 12/09/1999
• Issued: 06/19/2001
• Est. Priority Date: 06/11/1997
• Status: Expired due to Term

• Current Assignee: The United States of America, as represented by the Secretary, Department of Health and Human Services
• Original Assignee: United States Department Of Health And Human Services (Government of the United States of America)
• Inventors: Esswein, Eric J., Boeniger, Mark, Ashley, Kevin
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): Cross, LaToya I.
• Application Number:
  US09/458,152
• Time in Patent Office: 558 Days
• Field of Search: 436/77, 436/74, 436/172, 436/169, 436/73
• US Class Current: 436/77
• CPC Class Codes: G01N 31/22 using chemical indicators G01N31/02 takes precedence

Abstract

A method of detecting lead contamination of a surface is disclosed. A handwipe issued to collect any lead contamination on the surface. The lead is solubilized with an aqueous acid solution and treated with rhodizonate or sulfide anions. A change in color from pink to red, where rhodizonate anions are used, or brown to black, where sulfide anions are used, is indicative of the presence of lead. The method is suitable for testing surfaces such as floors, walls, windowsills, and human skin.

Claims

1. A method for the detection of lead on a surface suspected of lead contamination, said method comprising:

(a) wiping the surface with a handwipe whereby residue containing lead contamination, if present on the surface, is retained and collected on the handwipe;

(b) solubilizing any lead collected on the handwipe with an acidic aqueous solution having a pH of about 1 to about 5, wherein the acidic solution is not present on the handwipe during step (a) and, wherein the lead is solubilized on the handwipe;

(c) treating the solubilized lead with an anion selected from the group consisting of rhodizonate or sulfide; and

(d) observing the color formed in step (c);

wherein, if lead is present on the surface, the color formed is pink to red if the anion is rhodizonate or the color is brown to black if the anion is sulfide.

2. A method as defined in claim 1, wherein the acidic aqueous solution is sprayed directly on the handwipe and wherein a solution containing an anion is sprayed directly on the handwipe.

3. A method as defined in claim 1, wherein the acidic aqueous solution has a pH of about 1 to about 5, wherein the anion is rhodizonate, wherein the lead is solubilized and leached into the acidic aqueous solution, wherein the acidic aqueous solution is not present on the handwipe during the step of wiping the surface, and wherein the acidic aqueous solution containing solubilized lead is treated with the anion.

4. A method as defined in claim 3, wherein a chemical spot test is used in step (c).

5. A method as defined in claim 1, wherein the step of wiping the surface with the handwipe comprises wiping human skin with the handwipe and wherein the acidic aqueous solution is not present on the handwipe during the step of wiping the surface.

6. A method as defined in claim 1, wherein the step of wiping the surface with the handwipe comprises wiping human skin with the handwipe.

7. A method as defined in claim 2, wherein the step of wiping the surface with the handwipe comprises wiping human skin with the handwipe.

8. A method as defined in claim 3, wherein the step of wiping the surface with the handwipe comprises wiping human skin with the handwipe.

9. A method for the detection of lead on human skin suspected of lead contamination, said method comprising:

(a) wiping the skin with a handwipe whereby residue containing lead contamination, if present on the skin, is retained and collected on the handwipe;

(b) solubilizing lead in the residue containing lead contamination collected on the handwipe with an acidic aqueous solution;

(c) treating the solubilized lead with an anion selected from the group consisting of rhodizonate or sulfide; and

(d) observing the color formed in step (c);

wherein, if lead is present on the surface, the color formed is pink to red if the anion is rhodizonate or the color formed is brown to black if the anion is sulfide.

10. A method as defined in claim 9, wherein the acidic aqueous solution has a pH of about 1 to about 5, wherein the anion is rhodizonate, wherein the lead is solubilized directly on the handwipe, wherein the acidic aqueous solution is not present on the handwipe during the step of wiping the surface, and wherein the solubilized lead is treated with the anion directly on the handwipe, whereby, if lead is present, the color formed is observed on the handwipe.

11. A method as defined in claim 10, wherein the acidic aqueous solution is sprayed directly on the handwipe and wherein a solution containing the anion is sprayed directly on the handwipe.

12. A method as defined in claim 9, wherein the acidic aqueous solution has a pH of about 1 to about 5, wherein the anion is rhodizonate, wherein the lead is solubilized and leached into the acidic aqueous solution, wherein the acidic aqueous solution is not present on the handwipe during the step of wiping the surface, and wherein the acidic aqueous solution containing solubilized lead is treated with the anion.

13. A method as defined in claim 12, wherein a chemical spot test is used in step (c).

20. The method of claim 9, wherein the acidic aqueous solution contains acetic acid.

14. A method for evaluating the effectiveness of washing for removal of lead from an area of human skin, said method comprising:

(a) selecting an area of human skin in which the effectiveness of washing for removal of lead is to be evaluated;

(b) washing the area of human skin to remove lead;

(c) wiping the washed area of human skin with a handwipe whereby residue containing lead contamination, if remaining on the area of the human skin after washing, is retained and collected on the handwipe;

(d) solubilizing lead from the residue containing the contamination collected on the handwipe with an acidic aqueous solution having a pH of about 1 to about 5;

(e) treating the solubilizing lead with an anion selected from the group consisting of rhodizonate or sulfide; and

(f) observing the color formed in step (e);

wherein, if lead remains on the area of human skin after washing, the color formed is pink to red if the anion is rhodizonate or the color formed is brown to black if the anion is sulfide.

15. A method as defined in claim 14, wherein, if lead remains on the area of human skin after washing, steps (b) through (f) are repeated.

16. A method as defined in claim 14, wherein the anion is rhodizonate, wherein the lead is solubilized directly on the handwipe, wherein the acidic aqueous solution is not present on the handwipe during the step of wiping the washed area of human skin, and wherein, if lead remains on the area of human skin after washing, the color formed is observed on the handwipe.

17. A method as defined in claim 16, wherein the acidic aqueous solution is sprayed directly on the handwipe and wherein a solution containing the anion is sprayed directly on the handwipe.

18. A method as defined in claim 14, wherein the area of human skin is tested for the presence of lead before the washing of step (b).

19. A method as defined in claim 17, wherein the area of human skin is tested for the presence of lead before the washing of step (b).

21. The method of claim 14, wherein the handwipe contains at least one handwipe additive selected from the group consisting of surfactants, disinfectants, and lotions.