Ref. No. [UMCES]CBL 2013-021
ACT VS12-05
RESULTS of LABORATORY TEST
Laboratory tests of response factor, precision, range, and reliability were conducted at
Moss Landing Marine Lab utilizing five different challenge compounds covering a range of
fluorescent properties (see Table 1 above) to facilitate comparisons against the range of optical
detection windows utilized by participating hydrocarbon sensors. Tests were performed in
insulated 500 L, black acrylic tanks in a dark room using filtered deionized water (DI) as the
background medium (Photo 1). Reference samples of these challenge compounds were
characterized and quantified using EEMS on a FluorMax-2 (photo 2) over a range of
concentrations from 1 – 1000 ppb.
Photo 1.
Instrument Rack and tank.
Photo 2.
EEM’s Generatio
n
EEM fluorescence maps of each of the five challenge compounds, dosed at a
concentration of 50 ppb, are presented along with the region of the optical window of the
FLCDRTD fluorometer (Figure 1) filter set. Excitation and Emission maximums of the
challenge compounds varied by over 100 nm; however, none of the maximums matched the
optical window of the FLCDRTD filter set closely. Of the five compounds, the EEM maximum
of Quinine Sulfate mapped the closest. The response curves for the FLCDRTD fluorometer
measurements tested against NDSA, QS, Carbazole, BB3 and #2 Diesel fuel at concentrations
ranging from 1 – 1000 ppb (5000 ppb for QS) are shown in Figure 2. Results show instrument
response (in counts) presented against both concentration and estimated EEM
QSE
(Quinine
Sulfate equivalent) fluorescence intensity for each challenge compound. The baseline signal in
fresh DI ranged from 50 to 125 counts during four of the challenge trials (Fig. 2A). As expected
from the optical match-up noted in Figure 1, the concentration response was greatest for Quinine
Sulfate. Due to scheduling constraints, the fifth lab trial was conducted after field deployments.
