301 / 311
Page 6 of 8
Method Performance Feedback 2014.03
selected were noted in the Fitness for Purpose statement established by the Stakeholder Panel on Petroleum
Contaminants in Seafood in 2010. The ERP captured a revote.
1.
It was not advisable or possible to use this material in the Collaborative Study due to the cost of the material. It
also has analytes which are so low in concentration that NOAA labs had trouble getting repeatable quantitations.
The criteria for acceptance allowed for more that one analyte to be outside the acceptable range. It is hoped that
this new method may provide more sensitivity and precision but reproducibility data for the NIST reference
material using this new method is not yet available.
These comments were addressed in the writing of the 1st Action Method
Method is well-written but needs more specificity in select sections. For example, on page 6, under (5), it is
stated all
analytes of reagent blanks must be below the concentrations in the lowest calibration standard. Needs more
clarification....how far below? Also, since stability of some PAHs was questionable, a Stability Study needs to be
carried out
with PAH standards stored at varying temperatures and times. The Safety Section must be in the front of the
method since
safety is more important than any other part of the protocol.
This comment has not yet been addresses but could be a simple edit of the method if the ERP members agree.
The authors should use
correct nomenclature for the PAHs, i.e., Benzo[ghi]perylene not benzo[g,h,i]perylene
ERP may want to consider updates to the method as recommended by ERP3
Weaknesses include: 1. Method scope of 1 ug/kg LOQ of BaP was not tested as a fortification level. As I read the
method,
the lowest fortification level for BaP was 2 ug/kg. 2. Polypropylene tubes used for extraction will likely cause
users of the
method issues with PAH contamination. Discussion of alternatives would be helpful. 3. PAH GC-MS analysis has
significant
differences than typical analysis of most other types of compounds. Guidance for GC-MS parameters would likely
be helpful
for users of the method. These include parameters like inlet temperature, transfer line temperature, ion source
temperature,
column loadability and efficient flow conditions. 4. There is no recommendation on how to report data on
chrysene and
triphenylene if the recommended, but not required, 50% valley separation is not met. Can chrysene and
triphenylene be
reported together? 5. Ion ratios are mentioned as a requirement for identification but there is no indication as to
the RSD
value that is acceptable or some other qualification. 6. When a linear calibration curve is not possible, allowance
for a "wellcharacterized"
quadratic formula is made but with no discussion of what "well-characterized" means. Some guidance would
be useful because some user will not be accustomed using quadratic calibration curves.
This comment might be addressed in the method if agreed by the ERP
18.2 megaohm water should be used for any GC/MS method (page 9, Section C).