4,4'-Isopropylidenediphenol, bisphenol A (BPA), was derivatized to BPA-carboxymethylether (BPA-CME), BPA-carboxypropylether (BPA-CPE) and BPA-carboxybutylether (BPA-CBE), and then linked to bovine serum albumin (BSA). The BPA-BSA conjugates were injected into female New Zealand White rabbits, which then generated six kinds of polyclonal antibodies. In addition, BPA and bisphenol B (BPB)-enzyme conjugates were derivatized to BPA-CME, BPA-CPE, BPA-CBE, BPA-carboxyphenylether (CPhE) and BPB-CPE, and then linked to horseradish peroxidase (HRP). An enzyme-linked immunosorbent assay (ELISA) was developed and the specificity of the antibodies was confirmed by comparison with pre-immune serum and by competitive assays using different dilutions of BPA standards. Although anti-BPA antibodies cross-reacted with BPB by more than 13.6% at all dilutions used, cross-reaction with phthalates and phenols occurred only less than 0.1%. The combination with the highest sensitivity was obtained using anti-BPA-CME-BSA antibody and BPA-CPhE-HRP conjugate. ELISA successfully detected BPA in human serum at concentrations as low as 0.3 ng mL(-1), and over a measurable range of 0.3-100 ng mL(-1). Recovery tests were carried out by adding BPA to three kinds of human serum, and ranged from 89.7 to 97.3%, from 85.4 to 94.9% and from 81.9 to 97.4%, respectively. The correlation between the results from ELISA and gas chromatography-mass spectrometry (GC-MS) for BPA in spiked serum was r2 = 0.990, indicating that the proposed method is a potential tool for screening a large number of human serum samples.

An ultrasensitive and fully automated bioluminescent enzyme immunoassay (BLEIA) was developed for the detection of norovirus (NV) capsid antigen. In the evaluation tests with recombinant virus-like particles, the BLEIA demonstrated broad reactivity against several NV genotypes (genotypes 1, 3, 4, 7, 8, and 12 in genogroup I [GI] and genotypes 1, 2, 3, 4, 5, 6, 12, and 13 in GII), a wide dose-response range from 0.25 pg/ml to 10,000 pg/ml, and good reproducibility with low coefficients of variation (CVs) (within-run CVs of <2.8%, between-day CVs of <3.7%). In the evaluation tests with NV-positive fecal samples, a good correlation (y ‫؍‬ 0.66x ؊ 3.21, r ‫؍‬ 0.84) between the BLEIA and real-time quantitative reverse transcription-PCR was obtained. Furthermore, in the dilution test with NV specimens, the analytical sensitivity of NV was estimated to be 10 5 to 10 6 copies/g of fecal sample, indicating that the analytical sensitivity of the BLEIA is comparable to that of commercially available molecular methods. All assay steps are fully automated, the turnaround time is 46 min, and the throughput of the assay is 120 tests/h. These results indicate that the BLEIA is potentially useful for the rapid diagnosis of NV in epidemic and sporadic gastroenteritis.