SW-846 Method 0011
Sampling for Selected Aldehyde and Ketone Emissions from Stationary
Sources
Method Overview
- • Isokinetic sampling train.
- • Impingers are charged with DNPH reagent.
- • Train is cleaned up in the field with MeCl2.
- • Formaldehyde and other aldehydes and ketones react with
the DNPH to form derivatives.
- • The derivatives are extracted and analyzed by HPLC/UV.
Target Compounds
- • Validated: acetaldehye, acetophenone, formaldehyde, isophorone,
and propionaldehyde
- • Full Scan: acetaldehyde, acetone, acrolein, benzaldehyde,
butyraldehyde, crotonaldehyde, cyclohexanone, decyl alcohol aldehyde,
2,5-dimethylbenzaldehyde, formaldehyde, heptaldehyde, hexaldehyde,
isovaleraldehyde, nonanal aldehyde, octyl alcohol aldehyde, propionaldehyde,
tolualdehydes, valeraldehyde
Method Summary
- • Be advised
that acetone will contaminate the DNPH, be careful to bake probes
and other parts prior to reuse in a M0011 train. Acetone is ubiquitous
in stack sampling, and even when acetone is not a M0011 analyte,
at very high concentrations acetone can have a high bias on formaldehyde
results.
- • DNPH reagent is prepared in the lab and charged in the
field. Once charged, operate the train like a M5 train.
- • Be alert for orange or red crystals forming at the interface
of the reagent and the glass in the first impinger. This is often
a sign that the reagent has been consumed by too much formaldehyde
in the gas stream. At this point, try adding extra impingers and
reducing nozzle size. The sampling train normally saturates at 60-
100 ppmv formaldehyde in the stack.
- • Clean up the train with water and then with methylene chloride
until all yellow color is gone from impingers.
- • Enthalpy will extract the impinger contents then solvent
exchange to acetonitrile for analysis.
- • Analysis is by HPLC with UV detection at 370 nm. Standards
are prepped as DNPH derivatives of the corresponding aldehyde.
- • Acrolein problem - though on the scan list, acrolein typically
exhibits poor recoveries (‹40%) and should be avoided as a
M0011 analyte. However, acrolein works well in a Tedlar bag sample
by EPA M18 in low moisture sources. (See our summary "EPA Method
18 - VOC by GC - Flexible Bag Sampling".)
Quality Assurance
- • Field spike - typically ~ 800 ug of formaldehyde. (Place
the field spike into an impinger containing 200 mL of DNPH solution,
recover, and return for analysis.)
- • Laboratory control spike (LCS). Prepared and performed
by the lab, the LCS is analyzed in case of problems with the field
spike. (recovery of +/- 20%; - not required, but expected).
- • Method 0011 DOES require a "Sample Blank" - add a volume
of DNPH reagent and methylene chloride equal to the total volume
of the combined impingers and rinses.
- • Method 0011 DOES require a "Matrix Spike Sample." This
additional sample must be collected for use as a matrix spike sample
as described in Sec. 8.0 of Method 8315. Every effort should be
made to ensure that this sample represents the average stack matrix
of the sample batch.
- • The "Matrix Spike" should be a fourth train collected during
the same process conditions as the first three runs and preferably
operated simultaneously ("collocated") with one of the
sample trains so that the baseline concentration is the same in
both trains. The matrix spike train is then spiked AFTER collection.
Though the matrix spike is a considerable effort, failure to collect
it has caused the disallowal of entire M0011 projects. At least
consider asking approval to collect the much less onerous matrix
spike as specified in CARB 430, section 10.1.2. The CARB 430 matrix
spike procedure does not require a fourth run, with the lab performing
the additional QA procedures. (Call Enthalpy for details.)
- • Method 0011 does NOT require breakthrough checks.
- • Method 0011 does NOT require Field Blanks. Field blanks
may be submitted with the samples collected at each sampling site.
- • Method 0011 does require that DNPH be used no longer than
5 days after making and 2 days after opening the container in the
field.
- • The Method also requires that DNPH must be extracted within
7 days after testing.
Shipping Tips
- • DNPH/HCl and methylene chloride are both hazardous materials
and must be shipped as such. Call for IATA shipping codes if you
need them.
- • Ship using blue ice.
- • Important - include a complete Chain of Custody form for
EACH shipping container. (See our downloads section for a COC form.)
Enthalpy Experience
This is one of the four methods (TO-11, TO-5, Carb 430, M0011) that
Enthalpy offers that use the DNPH reagent. Our
full scan of aldehydes and ketones includes 18 compounds. See list
above in "Target Compounds" section.
