SKC 500-100 UMEx 100 Passive Sampler for Formaldehyde - Manual (Page 3)

1. Open the pouch and remove the sampler. Do not discard the pouch as it is used
to send the sampler to the laboratory. Store the pouch away from potential
formaldehyde sources.
Note: Included in the pouch is a small length of tape similar to the tape inside the
sampler. This tape protects the background of the sampler should any formaldehyde in
the atmosphere enter the pouch. Leave the tape inside the pouch at all times and send
along with the sample to the laboratory.
2. Enter the date and location in the space provided on the back of the sampler.
3. Enter the sample start time in the space provided on the back of the sampler.
Position the sampler on a worker’s collar for personal sampling or in an ap-
propriate location for area sampling.
4. Slide the sampler cover to the “on” position to begin sampling.
5. Aft er sampling for the desired time slide the sampler cover to the “off ” position
to stop sampling. Enter the sample stop time in the space provided on the back
of the sampler.
6. Place the sampler in the original pouch immediately aft er sampling.
7. Seal the pouch. Send pertinent information and the sample to an accredited
laboratory for analysis. Use expedited shipping.
Analysis Instructions
Derivative Preparation
Note: Prepared derivative standards are commercially available.
1. Add 10 ml of concentrated hydrochloric acid to 2 grams of
2,4-dinitrophenylhydrazine while stirring.
2. The yellowish crystal mass is dissolved in 200 ml of ethanol (95%).
3. Stir for 30 minutes, then cap the fl ask.
4. Filter to remove undissolved hydrazine hydrochloride.
5. Add 0.8 ml of 37% aqueous formaldehyde to form a yellowish precipitate.
6. Filter and wash the crystals with 5 ml of cold ethanol and recrystallize twice
by adding boiling ethanol (95%).
7. Prepare standard solutions in acetonitrile.
Sample Preparation
1. Remove the sampler from the pouch and the sliding
cover from the sampler. Use forceps (cleaned with
acetonitrile) to lift out the reactive tape from each
section. Place each in a sealed vial. This provides
a sample and a blank/correction.
Note: The blank/correction section of tape has an
indentation for easy identifi cation.
2. The formaldehyde 2,4-dinitrophenylhydrazone
is desorbed from both the sample and blank/cor-
rection tapes by placing each in its own 4-ml glass
vial containing 3.0 ml of acetonitrile and shaking
them by hand for one minute.
Sample Analysis
1. A 10-μl portion of the solution resulting from
Step 2 above is subjected to high-performance
liquid chromatographic (HPLC) determination
using an octadecylsilane column and a mobile
phase consisting of 33% water in methanol .
‡
Diffusion plate
Reactive tape (sample)
Collar clip
Body
Sliding
cover
Reactive tape
(blank/correction)