Evaluation of Handheld Assays for the Detection of Ricin and Staphylococcal Enterotoxin B in Disinfected Waters

Abstract

Development of a rapid field test is needed capable of determining if field supplies of water are safe to drink by the warfighter during a military operation. The present study sought to assess the effectiveness of handheld assays (HHAs) in detecting ricin and Staphylococcal Enterotoxin B (SEB) in water. Performance of HHAs was evaluated in formulated tap water with and without chlorine, reverse osmosis water (RO) with chlorine, and RO with bromine. Each matrix was prepared, spiked with ricin or SEB at multiple concentrations, and then loaded onto HHAs. HHAs were allowed to develop and then read visually. Limits of detection (LOD) were determined for all HHAs in each water type. Both ricin and SEB were detected by HHAs in formulated tap water at or below the suggested health effect levels of 455 ng/mL and 4.55 ng/mL, respectively. However, in brominated or chlorinated waters, LODs for SEB increased to approximately 2,500 ng/mL. LODs for ricin increased in chlorinated water, but still remained below the suggested health effect level. In brominated water, the LOD for ricin increased to approximately 2,500 ng/mL. In conclusion, the HHAs tested were less effective at detecting ricin and SEB in disinfected water, as currently configured.

Fate of Thallium(I) in Reverse Osmosis and Chlorinated Water Matrices

“…The equations for the dissociation of Tl 2 SO 4 into Tl + cation and SO 4 2-anion when dissolved in water are shown (eqs 1-3), and the formula for the stability constant of TlSO 4 -, β 1 is given (eq 4).…”

“…A prior study found that evidence for the existence of the ion TlSO 4 -in solution was inconclusive. 5 Glaser gives the stability constant, β 1 for the formation of TlSO 4 -in 2 M aqueous sodium perchlorate solution as 2.2, 6 and states that Tl + is only weakly hydrated in aqueous solution, and has a low tendency to form complexes.…”

“…The RO water was prepared by running regular tap water through an Osmo 23G RO system (GE Osmonics, Minnetonka, MN) RO unit and was the same as in previous projects. 3,4 The RO-Cl water was prepared by adding sodium hypochlorite (NaOCl) to the RO water to a final concentration of 2 ppm free chlorine as measured with a Hach AquaChek TruTest digital test strip reader (Hach Company, Elkhart, IN). The NaOCl solution was obtained from Sigma-Aldrich Chemical Company, item 425044-250ML, batch 09113ME, reagent grade, with 10-13% available chlorine.…”

Single Domain Antibodies for the Detection of Ricin Using Silicon Photonic Microring Resonator Arrays

“…14-20 Both PCR and catalytic activity assays are indirect methods for detecting ricin. PCR only detects nucleic materials from the plant origin of the toxin, and therefore is not applicable to detect purified ricin, 21, 22 while catalytic activity assays lack specificity towards ricin, since the catalytic activity of all RIPs are similar.…”

ELISA and SPR Studies of Ricin Binding to β-Galactoside Analogs

“…[10,11] Current point-of-care detection technologies use antibodies as the capture agent. [12,13] Antibodies are generally generated from immunized animals, and production and separation of ultrapure biomaterials in large quantities can be expensive. [14] Most antibodies require refrigeration, which can be a major concern if immunoassays are to be used in remote areas, where stability without refrigeration is desired.…”