LaMotte LEAD IN AIR User Manual
Page 2
PRO CE DURE
1.
Pour 10 mL of *Lead in Air Absorbing Solution (7668) into clean
impinging apparatus. Connect impinging apparatus to intake of air
sampling pump. Make sure the long tube is immersed in the absorbing
solution. Collect air sample at a rate of 1.0 Lpm for a period of 10
minutes or until a measurable amount of lead is absorbed.
2.
At the end of sampling period, measure pH of absorbing solution by
immersing end of pH strip (2950) into solution. Match the color of
the strip to the color chart. If pH is not within desired range (9-11)
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 between 9 and11.
3.
With special glass pipet, squeeze rubber bulb and insert pipet below
clear preservative layer in *Lead Reagent #1 (7664). Release bulb and
draw green solution into pipet until solution level is even with line.
Transfer to clean test tube (0843).
4.
Carefully add 5 drops of *Lead Reagent #2. Cap and shake vigorously
for 10-15 seconds.
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.
5.
Remove cap and allow test tube to stand undisturbed for 1 minute.
The layers will separate, producing a yellow to orange layer on top. If
a pink or red color is present in the bottom layer, rewash tube with
dilute acid and rinse with distilled water. Restart test.
6.
Dilute to 10 mL line with pH-adjusted Lead Absorbing Solution
(Step 2). Cap and shake vigorously for 30 seconds.
7.
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 within desired range (pH 9-11).
8.
Insert test tube into the Octet Comparator (7719). Match sample
color to a color standard. Record the index number which gives the
proper color match.
9.
Repeat Steps 2-9 with deionized water. Subtract result obtained from
test result.