LaMotte LEAD IN AIR TEST KIT - Manual (Page 5)

PRO CE DURE
1.
Fill a clean impinging tube to 10 mL line with *Lead In Air
Absorbing Solution (7668). Connect impinging apparatus to intake
of air sampling pump.
NOTE:
Make sure the long tube is immersed in the absorbing
solution.
2. Adjust flowmeter to collect air sample at 1.0 Lpm for 10 minutes, or
until a measurable amount of lead is absorbed.
3. Immerse end of pH Strip (3-2957) into solution. Compare the color
of the strip to the color chart. If pH is not between 9 and 11 adjust by
adding drops of *Sodium Hydroxide, 5N (6533) to raise the pH or
drops of *Hydrochloric Acid, 1N (6130) to lower pH. Make sure the
pH is adjusted to between 9 and 11.
4. With special glass pipet (0305), squeeze rubber bulb and insert pipet
below clear preservative layer in *Lead Dithizone Reagent (4227).
Release bulb and draw green solution into pipet until solution level is
even with line. Transfer to clean test tube (0843).
CAUTION:
*Lead Dithizone Reagent contains chloroform as a
solvent — avoid spills and breathing vapor. Use with adequate
ventilation.
5. Carefully add 5 drops of *Lead Reagent #2 (7665).
CAUTION:
*Lead Reagent #2 is an alkaline solution of cyanide and
should be handled with extreme care. Do not dispose of cyanide
solutions in presence of acids because the highly toxic HCN gas is
evolved.
6. Cap and shake vigorously for 10-15 seconds. Remove cap and allow
test tube to stand undisturbed for 1 minute. After 1 minute the layers
will separate, producing a yellow to orange layer on top. No pink or
red should be present in the bottom layer. If a pink or red color is
present, rewash tube with dilute acid, rinse with distilled water and
start procedure over.
7. Dilute to 10 mL line with pH adjusted Absorbing Solution from Step
3. Cap and shake vigorously for 30 seconds.
8. Allow test tube to stand undisturbed for 1 minute. If bottom layer
remains cloudy shake another 10-15 seconds. Check the pH to ensure
pH is between 9 and 11.
9. Insert test tube into the Lead In Air Comparator (4418). Match
sample color to index of color standards. Record the index number
which gives the proper color match.
10. Repeat Steps 3-9 on a blank of deionized water and subtract result
obtained from test result.