Testing a new technology, Solid-Phase Adsorption Toxin Tracking (SPATT), for application towards
field detection and monitoring of the hydrophilic phycotoxin domoic acid.
Jenny Q. Lane, Meiling Roddam, Raphael M. Kudela
Solid Phase Adsorption Toxin Tracking (SPATT) is a phycotoxin tracking methodology in which
artificial resin is used to passively adsorb toxins in water. First developed in New Zealand (MacKenzie et
al. 2004), this technology was subsequently put into limited use in the UK (Turrell et al. 2007) and
Australia (Takahashi et al. 2007), but remained untested in the US. Designed and tested for use with
lipophilic toxins [e.g. dinophysis-toxin (DTX-1), okadaic acid (OA), pectenotoxin (PTX-2), yessotoxin
(YTX), azaspiracid (AZA-1)], most initial laboratory trials and fieldwork exercises focused on the use of
DIAION HP20, a polyaromatic adsorbent resin (styrene-divinylbenzene matrix) suitable for passive
adsorption of lipophilic compounds. The development and use of SPATT technology suitable for use with
hydrophilic phycotoxins [e.g. domoic acid (DA)], was pursued to a more limited extent. Here, we present
results from laboratory trials and field deployments designed to develop, test, and optimize SPATT
technology for use with domoic acid in both the field and laboratory setting.
A
Domoic acid is a hydrophilic molecule, suggesting that
the SPATT resin identified as optimal for use with
lipophilic toxins, HP20, may have reduced applicability
in adsorption of this toxin and for its detection in the
field. As a starting point, we elected to test both the HP20
resin and a new resin recently identified as useful with
domoic acid (L. Turrell, pers. comm.). This new
polystyrene-based resin, SEPABEADS SP700, was
reported to have demonstrated good applicability towards
DA in terms of adsorption and recovery efficiency, and
was suggested as an excellent candidate for our trials. As B
a field component, we developed a SPATT bag
deployment design and maintained regular (~7d)
deployments of 100µm-mesh Nitex® bags each
containing 3g of HP20 and SP700 resins. These resins
were deployed alongside sentinel mussels that are
sampled and sent weekly to the California Department of
Public Health (CDPH) for biotoxin analysis as part of the
state-wide monitoring program. Results from these field
trials, ongoing since July 2008, will be presented
alongside laboratory trial results describing adsorption
and extraction efficiencies for both resins. Our
preliminary results for the adsorption of DA from DA-fortified Milli-Q by both the HP20 and SP700
resins are shown at right (Fig. A); our preliminary results from the subsequent extraction series is also
shown (Fig. B). While SP700 demonstrated superior adsorption efficiency over the HP20 resin, it
demonstrated a recovery efficiency that was substantially lower (~3% versus ~46%).
These preliminary results instigated an inter-laboratory comparison of SP700 extraction efficiency with L.
Turrell of the Fisheries Research Services (FRS) Marine Laboratory in Aberdeen, UK, and our
reconsideration of the previously described extraction protocol prescribed for use with SP700 and DA. In
addition, we sought alternative resins that might demonstrate more optimal extraction and adsorption
efficiencies, ultimately identifying (and evaluating) three additional resin candidates. In preliminary
laboratory trials of adsorption and extraction efficiencies, one of these resins demonstrated an adsorptive
efficiency that was substantially improved over the SP700 resin (SP207SS; >90% in <30 min.). These
results, and our suggestions for future work, will be presented.