Distribution of Chlorinated Hydrocarbon Pesticides and PCBs in the ...

mi = Ai x Wis/ (Ais x RRFi)
where mi = quantity of compound i found (in nanograms)
Ai
= peak area or height found for compound i
Wis = quantity of internal standard, in nanograms,
added to the sample (Fl) or fraction (F2 or F3)
Ais = peak area or height for the internal standard
RRFi= relative response factor for compound i with
respect to the internal standard.
3.1.9 Detection and Quantitation Limits
Detection and quantitation limits throughout this work are
defined as three and ten standard deviations, respectively, above
the mean procedural blank. These limits were determined
specifically for each substrate (i.e XAD-2 columns, 142mm glass
fibre filters, polyurethane plugs, and particulate high volume
air (PHVS) filters ) and procedural variants (i.e column
elution, filter homogenation, polyurethane air plug extaction,
tissue and sediment homogenisation, extraction and separation).
For each sample type, the following protocol was used;
1) the quantity of each compound of interest (tabulated in
nanograms) was blank corrected by subtraction of the mean
blank for that compound from the sample value.
if the blank corrected value was less three standard
deviations of the procedural blank, it was replaced by the
value (in nanograms) corresponding to three blank standard
deviations and preceded with the \