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This report describes a concept in which an immunoassay is used indirectly to quantify a nonantigenic very low molecular weight compound participating in a chemical reaction with a haptenic reporter. The detection limit of each reagent is, therefore, governed only by the affinity of the antibodies toward the reporter. Fluoride was used as a model, and silylated estradiol was used as a reporter. Upon silylation with N-O-bis(trimethyisilyl)trifluoroacetamide (BSTFA) or N-O-bis(dimethylterbutylsilyl) trifluoroacetamide (MTBSTFA), estradiol is no longer recognized by antibodies specific to estradiol. After reaction with hydrofluoric acid (HF) or fluoride salts (KF, CsF, NaF), its immunoreactivity is restored, and native estradiol is formed and is detected by immunoassay. The level of synthesized estradiol is dependent on the concentration of fluoride. A fluoride detection limit of 0.3 [micro]g/L (15 nM) is obtained. Potential interference with other acids has been eliminated by choosing the silyl group (trimethylsilyl vs tert-butyldimethylsilyl) and by selecting optimal reaction conditions for the desilylation. The method has been applied to the detection of fluoride salts in natural waters (range 0.28-9.0 mg/L) and in an atmosphere artificially contaminated with HF between 8 and 160 [micro]g/[m.sup.3] in the parts-per-billion range. This indirect immunoassay combines simplicity and high sensitivity and, therefore, can be used in field monitoring. Finally, the extension of the concept to other chemicals is discussed.

Research has been conducted on the 12-amino alkylidenecyclopentenone prostaglandins. The results of the enantioselective synthesis of these prostaglandins which involves sigmatropic rearrangement of the asymmetric allylic cyanate are presented.

Research has been conducted on the acetylcholinestrase, the enzyme regulating neurotransmission. The activity of this enzyme has been investigated and the description of the 1,3-dioxetane chemiluminescent probe generated in search for a sensitive detection assay is presented.

We report here our preliminary results on the use of catalytic antibodies as an approach to neutralizing organophosphorus chemical weapons. A first-generation hapten, methyl-[Alpha]-hydroxyphosphinate Ha, was designed to mimic the approach of an incoming water molecule for the hydrolysis of exceedingly toxic methylphosphonothioate VX (1a). A moderate protective activity was first observed on polyclonal antibodies raised against Ha. the results were further confirmed by using a mAb PAR 15 raised against phenyl-[Alpha]-hydroxyphosphinate Hb, which catalyzes the hydrolysis of PhX (1b), a less toxic phenylphosphonothioate analog of VX with a rate constant of 0.36 [M.sup.-1] [multiplied by] [min.sup.-1] at pH 7.4 and 25 [degrees] C, which corresponds to a catalytic proficiency of 14,400 [M.sup.-1] toward the rate constant for the uncatalyzed hydrolysis of 1b. This is a demonstration on the organophosphorus poisons themselves that mAbs can catalytically hydrolyze nerve agents, and a significant step toward the production of therapeutically active abzymes to treat poisoning by warfare agents.