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Imidacloprid (IMP) is toxic and a potential carcinogen that is most widely used as an insecticide for pest control and seed treatment. It is important to produce a rapid and sensitive assay for on-site monitoring. We have developed a novel lateral flow assay (LFA) using a sensitive monoclonal antibody (mAb) for monitoring IMP residues on fruits and vegetables. The 50% inhibition concentration result that was found when using the ELISA method was 0.247 ng mL−1, with the cut-off limits using the LFA method the result was 10 ng mL−1 (0.01 M PBS), and in the samples it was 20 ng mL−1 (with a recovery rate of 96–104.7% for Chinese cabbage, cowpea, apple, and pear samples, respectively). All of the results can be determined within seven minutes. The proposed LFA method is a valid, quick, and stable assay for the on-site detection of IMP in large numbers of samples. [ABSTRACT FROM AUTHOR]

A monoclonal antibody against triamcinolone acetonide (TCA) and budesonide (BUD) was prepared using a hapten that was generated by introducing a carboxyl group into the structure of TCA. Based on the prepared monoclonal antibody, a gold nanoparticle-based lateral-flow immunoassay (GLFA) was developed with the ability to screen TCA and BUD in milk. The visible limits of detection of the GLFA for the analysis of TCA and BUD were 0.1 and 0.5 ng/mL with a cutoff value of 5 and 10 ng/mL, respectively, in milk. Average recoveries of TCA and BUD in milk were 92.0–102.2% and 96.0–98.8% with a good correlation between the results from the GLFA and LC-MS/MS analysis. These results demonstrated that the GLFA method for the rapid detection of TCA and BUD in milk samples is reliable and sensitive. [ABSTRACT FROM AUTHOR]

Butralin is a dinitrobenzene pesticide, has been widely used as a herbicide in many crops. Its high levels of residues threaten the ecological balance and human health. Therefore, establishment of a sensitive monoclonal antibody (mAb) for rapid detection of butralin residues is critical. In this study, special haptens were designed with good preservation of the characteristic structure of target compound. After mice immunization, a highly sensitive monoclonal antibody was produced. The half-maximum inhibitory concentration (IC 50) was 1.936 ng/mL. And we applied it to develop a method of lateral flow immunoassay (LFIA), with vLOD value of the LFIA strip to be 10 ng/mL. In watermelon and pear samples, the cLOD values of the LFIA strip were 0.432 ng/mL and 0.426 ng/mL, respectively. The recoveries of the developed method ranged from 94.4% ± 2.1%–112.1% ± 3.4% and 89% ± 5.4%–103% ± 4.1% in watermelons and pears samples, with a CV of 2.9%–3.4% and 2.2%–5.2%, respectively. The results demonstrated that the developed method showed great prospect in the detection and monitoring of butralin in real food samples. • New haptens of butralin was synthesized successfully. • Based on the anti- butralin monoclonal antibody, the strip assay was established. • The visual detection limit for flumioxazin was 5 ng/mL. • The strip assay can be applied in on-site monitoring of watermelon and pear samples. [ABSTRACT FROM AUTHOR]

• A novel AMT hapten was designed by adding a carboxyl group with 4-C spacer arms. • The sensitive and specific anti-AMT mAb was prepared based on hapten design. • The immunochromatographic assay was firstly developed for AMT rapid detection. • The established mehod can meet the requirements of MRLs for AMT residues in foods. Amitraz (AMT) is a broad-spectrum formamidine insecticide and acaricide. In this study, we produced an anti-AMT monoclonal antibody (mAb) with high performance. The half-maximal inhibitory concentration of the anti-AMT mAb was 4.418 ng/mL, the cross reactivity with other insecticides was negligible, and an affinity constant was 2.06 × 109 mmol/L. Additionally, we developed an immunochromatographic assay for the rapid detection of AMT residues in oranges, tomatoes, and eggplants. The cut-off values were 2000 μg/kg in oranges and tomato samples and 1000 μg/kg in eggplant samples and the calculated limits of detection were 14.521 μg/kg, 6.281 μg/kg, and 3.518 μg/kg in oranges, tomatoes, and eggplants, respectively, meeting the detection requirements for AMT in fruits and vegetables. The recovery rates ranged between 95.8 % and 105.2 %, consistent with the recovery rates obtained via LC-MS/MS. Our developed immunochromatographic assay can effectively, accurately, and rapidly determine AMT residues in oranges, tomatoes, and eggplants. [ABSTRACT FROM AUTHOR]

Butralin is a widely used dinitroaniline herbicide. Butralin residues in vegetables or fruits represent a threat to human health. In this study, we developed a rapid and sensitive gold-based lateral flow immunoassay (LFIA) for butralin detection in tomato and green pepper samples based on a screened monoclonal antibody (mAb) against butralin. The mAb possessed a half-maximal inhibitory concentration (IC50) of 12.7 ng/mL, with no cross-reactivity toward other dinitroaniline herbicides. The established LFIA strip had a visible limit of detection (LOD) of 50 ng/g and a cut-off value of 2000 ng/g in tomato and green pepper samples. According to the calibration curves for quantitative analysis, the calculated LODs of the LFIA strip were 4.7 ng/g and 4.3 ng/g in tomato and green pepper, respectively. The results were obtained within 10 min. The average recoveries ranged between 95.4% and 109.6% with a coefficient of variation (CV) of 4.3% to 7.1% in tomato samples and between 94.8% and 109.1% with a CV of 3.9% to 6.1% in green pepper samples. These data suggested that our proposed LFIA is a sensitive, specific, and reliable method for the rapid detection of butralin in real samples. [ABSTRACT FROM AUTHOR]

In this study, a monoclonal antibody (mAb) 1G5 against novobiocin with high sensitivity and specificity was prepared from a newly-designed hapten. According to the results of an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA), the 50%-inhibitory concentration of the anti-novobiocin mAb was 6.9 ng/mL and the cross-reactivity was less than 0.1% to its analogues. Furthermore, a rapid colloidal gold immunochromatographic assay (ICA) was successfully developed for the determination of novobiocin in spiked samples. Two calibration curves were established respectively, for beef and chicken samples. The ICA results showed a visual colorimetric value of 50 ng/mL and a cut-off value of 300 ng/mL in beef samples. The ICA results of chicken samples were almost the same as that of beef. When quantitative detection was performed using a strip reader, the detection ranges for quantitative analysis in beef and chicken were 23.7–287.5 and 19.7–263.8 µg/kg respectively. Recoveries were between 82.7 and 95.3% for beef samples with the coefficient of variation (CV) ranging from 2.5 to 5.1%. Recoveries were in the range of 89.6–105.5% with the CV ranging from 2.9% to 6.3% for chicken samples. Importantly, these results from the ICA were highly consistent with the results obtained by LC-MS/MS. Therefore, this ICA could be used as an alternative means for the rapid determination of NOV in a large number of beef and chicken samples. [ABSTRACT FROM AUTHOR]

We have developed a sensitive and rapid gold nanoparticle-based immunochromatographic strip (GNP-ICS) for the detection of bifenthrin (BF) using an anti-BF monoclonal antibody (mAb). When used in indirect competitive enzyme-linked immunosorbent assay (icELISA), the specific anti-BF mAb (3D1) had a half-maximal inhibitory concentration (IC50) and limit of detection (LOD) of 59 and 15 ng mL−1 respectively. Additionally, its cross-reactivity (CR) with other pyrethroids was negative. The developed GNP-ICS assay based on the GNP-labelled mAb was specific and sensitive for determining BF, with a cut-off value of 1,000 ng mL−1, and a visual LOD (vLOD) value of 50 ng mL−1. Furthermore, the developed icELISA and GNP-ICS were applied with a simple pre-treatment to determine BF-spiked vegetable samples, and the recoveries were validated using gas chromatography-mass spectrometry (GC-MS). The results revealed that the developed GNP-ICS was reliable for the detection of BF in practical samples. [ABSTRACT FROM AUTHOR]

We designed and synthesized novel haptens to produce monoclonal antibodies (mAb) against vitamin B6 (VB6). A group-specific mAb (2F9) that recognized pyridoxine (PN), pyridoxamine (PM), and pyridoxal (PL) was prepared using a homologous strategy with 50% maximal inhibitory concentration (IC50) values of 106.60, 250.57, and 400.11 ng/mL, respectively. Based on this, a gold nanoparticles (AuNPs)-based immunochromatographic strip (ICS) test was established for the detection of VB6 in energy drinks and B-vitamin complex tablets. The developed ICS test results could be semi-quantitatively evaluated by the naked eye within 10 min, and displayed the visual limit of detection (vLOD) values of 250, 500, and 1,000 ng/mL for PN, PM, and PL, respectively. For quantitative analysis, the results obtained by strip reader, with calculated LOD values for PN, PM, and PL were 14.10, 55.58, and 56.25 ng/mL, respectively. Commercial energy drinks and B-vitamin complex tablet samples were detected by the strips and the results were confirmed with high-performance liquid chromatography. Overall, the developed AuNPs-based immunochromatographic sensor was suitable and promising for the group-specific recognition and rapid detection of VB6 in fortified foods and dietary supplements. [ABSTRACT FROM AUTHOR]

As a typical triazole fungicide, penconazole (PEN) is widely used in agriculture but has been proven to be toxic. In this study, we designed a new hapten to prepare a highly sensitive and specific anti-PEN monoclonal antibody (mAb) and established a gold nanoparticle-based lateral-flow immunoassay (LFIA) for the detection of PEN residues in watermelon and cucumber. The 50% inhibitory concentration (IC50) of the mAb was 0.42 ng/mL and the LFIA strip had a visual limit of detection (vLOD) of 2.5 ng/g and a cut-off value of 10 ng/g in watermelon and cucumbers. The calculated limit of detection (LOD) of the LFIA strip was 0.36 ng/g for watermelon and 0.29 ng/g for cucumber. The LFIA strip also gave a recovery rate of 92.5%–109.0% for watermelon samples and 92.5%–106.7% for cucumber samples. These results using the LFIA strip are highly consistent with those seen using liquid chromatography–tandem mass spectrometry. Thus our developed LFIA strip represents a potentially reliable tool for the rapid on-site screening for PEN in watermelons and cucumbers. [ABSTRACT FROM AUTHOR]

As a common class of growth regulators, gibberellins (GAs) are widely used in agricultural production. However, the abuse and misuse of GAs have led to the problem of high residues in crops. The existing detection methods are still mainly instrumental, and rapid and sensitive detection of GAs remains a challenge. In this study, we designed a novel hapten scheme by analyzing the structure of GAs, which enabled the prepared mAb to simultaneously detect common GAs (GA 3 , GA 1 , GA 4 and GA 7) with high sensitivity and homogeneity. Subsequently, a colloidal gold immunochromatographic assay (GICA) for GAs detection was established by combining mAb with synthetic gold nanoparticles, which could simplify the sample pre-treatment step and the calculated limit of detection, visual limit of detection, cut-off values and linear ranges were 0.09 mg/kg, 0.2 mg/kg, 8 mg/kg, 0.13–1.36 mg/kg for rice and 0.11 mg/kg, 0.2 mg/kg, greater than 8 mg/kg, 0.13–2.45 mg/kg for tomatoes. The recovery assays of GA 3 -spiked samples ranged between 95.1% and 105.1%. The results indicate that our developed method can be used for the rapid, sensitive and efficient on-site detection of GAs in food. • A GA 3 -hapten was designed to produce a highly sensitive and versatile mAb. • A visual immuno-sensing platform was developed. • The results showed a visual LOD of 0.2 mg/kg in rice and tomato samples. • No significant difference in recovery rates were seen between GICA and ic-ELISA. [ABSTRACT FROM AUTHOR]

In this study, a high sensitivity and specificity monoclonal antibody (mAb) was developed based on the hydroxy and carboxy-termini of ochratoxin A (OTA). A fluorescent microsphere immunochromatographic test strip (FM-ICTS) was assembled for the rapid detection the OTA in rice flour. Some relevant parameters were optimized including the best concentration of coating antigen and optimal diluent buffer composition. Under optimal conditions, the strip assay had a visual limit of detection (LOD) of 2 ng/mL and a cut-off value of 16 ng/mL for OTA in rice flour samples. By means of a strip scan reader, we obtained a quantitative measurement for OTA with an LOD of 1.27 ng/mL. No significant difference in the strip test results was seen when compared to an ic-ELISA assay or LC–MS/MS. This also shows, therefore, that the FM-ICTS has potential application for rapid and accurate quantitative detection in the market place. [ABSTRACT FROM AUTHOR]

In this study, a monoclonal antibody with selectivity for clopidol was produced based on a new hapten. The 50% inhibition concentration (IC50) for the developed ic-ELISA was 0.275 ng/mL. Cross-reactivity tests showed that the monoclonal antibody had high specificity for clopidol. Using this antibody, a lateral-flow colloidal gold immunoassay (LCGA) was created for the rapid screening of clopidol in raw chicken samples. With the naked eye, the cut-off value of the strip assay was 5 μg/kg for clopidol in chicken samples. Therefore, this LCGA provides a sensitive and rapid method for on-site detection of clopidol in chicken samples. [ABSTRACT FROM AUTHOR]

In developing countries, pesticides such as triazophos (TZP) are widely used in agriculture. However, the misuse TZP poses a threat to human health and the environment due to its high chemical and photochemical stability. In this study, we developed a lateral flow assay to determine TZP in cucumber. We produced anti-TZP monoclonal antibody with half inhibitory concentration of 2.013 ng/mL according to ELISA. Under optimum conditions, the lateral flow assay had TZP cut-off values of 100 ng/mL in 0.01 M PBS and 250 ng/mL in cucumber, and the results could be visualised with the naked eye in 5 min. our findings revealed that lateral flow assay is a rapid and sensitive method for detect TZP in cucumber. [ABSTRACT FROM AUTHOR]

Citreoviridin (CTV) is a toxic secondary metabolite that can be found in mouldy cereals. In this study, a sensitive and ethanol-tolerant anti-CTV monoclonal antibody (6B2) was produced with a 50% inhibition concentration of 4.1 ng/mL and then labelled using gold nanoparticle (GNP). Based on competitive inhibition of the binding of CTV-COOH-BSA conjugate sprayed onto a membrane to limited GNP-labelled antibody by free CTV in the samples, an easy-to-operate immunochromatographic strip (ICS) was developed for the fast screening of CTV in rice. The results are seen as a colour change within 5-10 min. We used relatively safe ethanol instead of highly toxic methanol or chloroform as the extraction solution and found a visible detection limit of 100 μg/kg and cut-off value of 1000 μg/kg. The developed ICS assay worked well and represented a reliable, safe, fast and a highthroughput method for the detection of CTV residues in rice samples. [ABSTRACT FROM AUTHOR]

In this study, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and a gold immunochromatographic assay were developed to detect the furaltadone metabolite, 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ). The detection of AMOZ was based on the AMOZ derivative 3-([2-nitrophenyl] methyleneamino)-5-morpholinomethyl-2-oxazolidinone (2-NPAMOZ). The monoclonal anti-2-NPAMOZ antibody 4G11, was prepared and exhibited a 50%-inhibitory concentration (IC50) of 0.049 ng/mL. Its cross-reactivity with structurally related analogues was less than 3%. This immunochromatographic assay was assembled for the rapid screening of AMOZ in catfish samples. The strip assay had a cut-off value of 0.1 μg/kg and a limit of detection (LOD) of 0.009 μg/kg. Analysis of AMOZ in catfish indicated that the results from the strip assay were highly comparable to results obtained using ic-ELISA and LC-MS/MS. Therefore, the colloidal gold (CG) immunoassay is a sensitive screening method for the detection of AMOZ residues in catfish samples. [ABSTRACT FROM AUTHOR]

In this study, we developed a monoclonal antibody against picoxystrobin (PIC). After cell fusion, four cell lines (3C2, 4D1, 4G4 and 5D4) capable of producing monoclonal antibodies against oxystrobin were obtained. The monoclonal antibody produced by the cell line 3C2 was the most sensitive to PIC, and its IC50 value was 0.1 ng/ml. The monoclonal antibody was then used to prepare immunochromatographic strips, and its cut-off values in both phosphate-buffered saline solution and cucumber samples were 50 and 100 ng/ml, respectively. It was concluded that the ICS can sensitively and rapidly detect PIC in cucumber samples. [ABSTRACT FROM AUTHOR]

In this study we developed a rapid and simple assay to detect RFP in fish using an immunochromatographic assay. We produced a sensitive and selective monoclonal antibody against RFP with a half-maximal inhibitory concentration (IC50) of 10.7 ng/mL. Fish samples were extracted with ethyl acetate, then centrifuged at 8000 rpm for 10 min, and concentrated by drying over nitrogen. We found under optimal conditions, that the RFP cut-off limits for the test strip was 10 µg/mL in both 0.01 M phosphate buffered saline and fish samples, and each test could be completed within 5 min. Therefore, immunochromatographic test can be used as a reliable, rapid, and sensitive method for the detection of RFP in fish. [ABSTRACT FROM AUTHOR]

In this study, we produced a monoclonal antibody (mAb) 2F7 against cadmium (Cd) with IC50 of 0.20 ng/mL. The cross-reactivity of mAb 2F7 with other eight metals was < 1%. A fluorescent immunoassay strip was developed for the determination of Cd in rice. The cut-off value by visual inspection of the test strip was 50 μg/kg, and the quantitative detection range determined by the strip reader was 3.86–48.92 μg/kg. Both ic-ELISA and the fluorescent immunoassay strip can be used to detect Cd rice. Therefore, our developed fluorescent immunoassay strip may be an effective tool for detecting Cd in rice. [ABSTRACT FROM AUTHOR]

Lead (Pb) is a toxic metal that can accumulate in the body and negatively impact human health. In this study, we prepared a highly sensitive and specific monoclonal antibody, 2C3, that can recognize Pb(II) with an IC50 and linear range of 0.5 ng/mL and 0.08–1.86 ng/mL, respectively. Additionally, based on this antibody we developed a fluorescent test strip, which can be used for both qualitative and quantitative detection of Pb(II) in brown rice with a detection range of 4.67–47.8 ng/mL. Therefore, the method we developed has high sensitivity suitable for the detection of Pb(II) in brown rice. [ABSTRACT FROM AUTHOR]

In this study, we produced a specific monoclonal antibody (mAb) against triadimefon (TDF) and triadimenol (TDN). The half-maximal inhibitory concentration for TDF and TDN was 5.25 and 9.98 ng/mL, respectively, with a linear detection range (IC20–IC80) of 1.09–25.35 and 2.29–43.61 ng/mL, respectively. Subsequently, we developed a colloidal gold immunochromatography test strip for the analysis of TDF and TDN in tomato. The results obtained from the colloidal gold immunochromatography test strip were in accordance with those obtained from the indirect competitive enzyme-linked immunosorbent assay. The colloidal gold immunochromatography test strip is efficient and suitable for on-site detection of TDF and TDN. [ABSTRACT FROM AUTHOR]

A monoclonal antibody against carazolol (CRZ), 2F5, was generated for the construction of an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and an immunochromatographic strip for detection of CRZ in milk and pig kidney samples. The antibody had a half-maximal inhibitory concentration of 0.29 ng/mL; its limit of detection was 0.068 ng/mL, and its linear range of detection was 0.137–0.638 ng/mL. For CRZ in milk samples and porcine kidney samples, the detection limits for this strip were 0.25 and 2.5 ng/mL, respectively. Analysis of CRZ in milk samples showed that the results obtained by immunochromatographic strip were consistent with those obtained by ic-ELISA. Therefore, the CG immunoassay is a sensitive screening method for semi-quantitative and qualitative detection of residual CRZ in milk and porcine kidney samples. [ABSTRACT FROM AUTHOR]

Aminophylline (AMP), a bronchodilator drug, is a modified form of theophylline (the pharmacological active ingredient). AMP is often given to treat respiratory diseases, including bronchial asthma, blocked emphysema, panting bronchitis, and cardiogenic asthma. In this study, we developed a rapid and sensitive method to determine AMP concentration in mouse serum. A sensitive monoclonal antibody against AMP was produced by immunizing BALB/c mice with a well-characterized AMP2-keyhole limpet hemocyanin and coating antigen (hapten-AMP1-OVA). The coating antigen and goat anti-mouse IgG antibody were sprayed onto a nitrocellulose membrane representing the test and control lines, respectively. Under optimized conditions, the cut-off limits of the test strip were 50 ng/mL in 0.01 M phosphate buffered saline (pH 7.4) and 250 ng/mL in serum. The results were obtained within 10 min and revealed that this immunochromatographic strip test is a sensitive, rapid, and simple tool for the detection of AMP in serum. [ABSTRACT FROM AUTHOR]

Cyclopiazonic acid (CPA) is an indole‐tetramine mycotoxin commonly produced by Penicillium and Aspergillus and is widely found in agricultural products, fermented food, and feed. Food contaminated with CPA poses a substantial health risk to consumers. Therefore, eco‐friendly immunoassays, including an indirect competitive enzyme‐linked immunosorbent assay (ic‐ELISA) and a lateral flow immunochromatographic strip (LFICS), were developed to monitor CPA in maize and rice samples. For this purpose, a monoclonal antibody (3H12) posed highly resistant to pH (5.6 to 9.6) and ethanol (≤50%) was generated by mouse immunization. Negative maize and rice samples or samples spiked with CPA were extracted with ethanol/0.01 M sodium borate buffer (4/1, v/v, pH 8.4). For ic–ELISA analysis, the limits of detection (LODs) were 0.48 and 0.28 ng/g for maize and rice samples, respectively. The recovery for spiked maize was 76.9% to 83.5% with the highest variable coefficient (CVmax) being 9.32%. For spiked rice, the recovery was 85.3% to 105.1% with a CVmax of 8.56%. For LFICS analysis, the visible LODs were 2.5 and 1 ng/g and cutoff values were 5 and 2.5 ng/g for maize and rice samples, respectively. The LFICS method gave results within 5 to 10 min, providing an auxiliary analytical tool for the rapid, sensitive, and portable screening of the massive samples onsite. [ABSTRACT FROM AUTHOR]

In this study, a kitasamycin (KIT) hapten was prepared through the o-carboxymethoxylamine method and used to produce a monoclonal antibody against KIT and josamycin (JOS). The half inhibition concentration for an indirect competitive enzyme-linked immunosorbent assay was 1.49 and 2.67 ng/mL, respectively. Based on this antibody, a gold immunochromatographic assay (GICA) was developed for the detection of KIT and JOS residues in milk and egg samples. A hand-held strip scanner was used for quantitative analysis, with limits of detection for KIT and JOS of 1.51 and 1.91 μg/L in milk, and 3.0 and 2.72 μg/kg in eggs. The proposed GICA was validated by LC–MS/MS, which indicated that the GICA method would be a useful tool for the on-site detection of KIT and JOS residues in milk and egg samples. [ABSTRACT FROM AUTHOR]

Praziquantel (PZQ) is a broad-spectrum antiparasitic drug used in mammals and fish. In this study, we developed an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) for the detection of PZQ residues. The hapten PZQ-HS produced by introducing an amino group at a benzene ring synthesized the immunogen and the coating antigen with carrier proteins. Highly sensitive monoclonal antibodies (mAbs) were prepared following mouse immunization and cell fusion. Under optimum conditions, the half maximal inhibitory concentration of the cell line 4E9 was 7.4 ng/mL, and the working range was 2.4–22.8 ng/mL. Immunochromatographic strips (ICS) were developed for the rapid detection of PZQ residues in mackerel. The reliability of the ICS assay was verified with PZQ-negative mackerel and confirmed by HPLC/MS. The cutoff value for ICS was 50 ng/mL PZQ. Our findings revealed that ic-ELISA and ICS can be used for the rapid detection of PZQ in mackerel. [ABSTRACT FROM AUTHOR]

A monoclonal antibody (mAb), 2C9, selective for four eugenol compounds, was developed based on the eugenol derivatives (Eug-1). The semi-inhibitory concentrations (IC50) of this antibody against eugenol, isoeugenol, methyl eugenol, and methyl isoeugenol were 0.043, 0.302, 0.016, and 0.082 μg/mL, respectively, and the detection limits (LOD) were 0.012, 0.070, 0.004 and 0.024 μg/mL. With the exception of isoeugenol, which had cross-reactivity of less than 15%, the cross-reactivity of the other compounds was good, ranging from 52.4% to 269%. In the ic-ELISA recovery test, recovery was between 80% and 94%, indicating that the method was suitable for analysis of eugenol compounds in water. The cut-off values of the immunochromatographic strips for the four compounds in water were 5, 100, 100, and 100 μg/mL, respectively, indicating that the ic-ELISA and immunochromatographic strips we developed can be used to rapidly detect eugenol compounds in water. [ABSTRACT FROM AUTHOR]

In this study, we prepared a monoclonal antibody against pyrimethanil, for which we first derived its hapten according to the structural formula of pyrimethanil; we used indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) to screen positive mice for cell fusion; finally, we developed five cell lines (1A5, 1E7, 3A6, 3H12 and 5D4) that produced monoclonal antibodies to pyrimethanil. The monoclonal antibody produced by each cell was detected by ic-ELISA, and the monoclonal antibody produced by the 1E7 cell strain was found to be the most sensitive to pyrimethanil. The IC50 value of this antibody was 4 ng/ml. After using this monoclonal antibody, i.e. 1E7, to perform immunocolloidal gold strip treatment on cucumber samples, the PBS and the cucumber samples cutoff value of Immunochromatographic strips (ICS) was found to be 50 ng/ml; We conclude that ICS can rapidly detect pyrimethanil in cucumber samples. [ABSTRACT FROM AUTHOR]

A rapid, specific and sensitive method based an immunochromatographic strip test has been developed for the determination of sodium nifurstyrenate (NFS) residues in fish. Sample preparation procedure includes ultrasonic bath extraction with acetonitrile, sample centrifugation at 8000 rpm for 10 min, filtration through the 0.22 µm membrane filter, and drying over nitrogen (60°C) and res-suspension. The antigen (NFS-ovalbumin) and a goat anti-mouse IgG antibody were drawn onto a nitrocellulose membrane as the test line and control line, respectively. Under optimized conditions, the NFS cut-off limits for test strips was determined as 5 ng/mL in 0.01 M phosphate buffered saline and 10 ng/mL in fish. Results were obtained within 5 min. Our data suggests this immunochromatographic assay can be used for the sensitive, rapid, and specific on-site screening for NFS in fish. [ABSTRACT FROM AUTHOR]

A highly sensitive, specific, and rapid immunochromatographic assay for halofuginone (HFG) has been developed. A well-characterized immunogenic conjugate of HFG with bovine serum albumin was produced using the N,N″-Carbonyldiimidazole method. A sensitive monoclonal antibody specific for HFG was then generated by immunizing BALB/c mic with the HFG conjugate. The antigen, HFG-CDI-ovalbumin and goat anti-mouse IgG were attached to a nitrocellulose membrane as the test line and the control line, respectively to produce an immunochromatographic test strip for the rapid detection of HFG in milk. Under optimized conditions, the detection limits of the semi-quantitative test strip for HFG were as low as 50 ng/mL in 0.01 M PBS (pH 7.4) and 100 ng/mL in milk. All the results were obtained within 5 min. The newly developed immunochromatographic assay provides a sensitive, rapid, and specific procedure for on-site screening for HFG. [ABSTRACT FROM AUTHOR]

In this study, we prepared a highly sensitive monoclonal antibody (mAb) against Cyhalofop-butyl (Cyh) by indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). Based on this mAb, an immunochromatographic strip (ICA) was established to detect Cyh in corn and brown rice samples. Through screening different coating antigens and antibodies, the half-maximum inhibitory concentration (IC 50) of the highly specific Cyh mAb 1A3 was 2.2 ng/mL, and the detection linear range (IC 20 -IC 80) was 0.5–5.2 ng/mL. When Cyh in corn samples was detected by ICA, the detection limit of the T line elimination value was 100 μg/kg, and the detection limit for colorimetric value was 25 μg/kg. When the detection sample was brown rice, the detection limit of the T line elimination value was 100 μg/kg, and the detection limit for colorimetric value was 12 μg/kg. The results of recovery experiments for both ic-ELISA and LC-MS/MS were consistent with those of the test results when using the ICA. The ICA test strip met the requirements for on-site rapid detection of Cyh in corn and brown rice samples. Therefore, this method is suitable for real-time detection and monitoring of agricultural products as well as during plant growth, harvesting, transportation, storage, and sales, thereby guaranteeing the safety of consumers. [ABSTRACT FROM AUTHOR]

The problem of waste oil is a food safety issue that requires urgent resolution. In this study, a novel hapten was designed for the rapid detection of capsaicinoids, a marker of waste oil, and a monoclonal antibody (MAb) 5D7 was generated that is specific for three major capsaicinoids: capsaicin (CPC), dihydrocapsaicin (DCPC), and N-vanillylnonanamide (N-V). The half maximal inhibitory concentrations of MAb 5D7 for CPC, DCPC, and N-V were 1.12, 0.8, and 0.87 ng/mL, respectively. An immunochromatographic strip test based on MAb 5D7 was established for these three capsaicinoids, with visual inspection limits of <1.0 ng/mL, which satisfies the requirement for the rapid on-site inspection of waste oil. [ABSTRACT FROM AUTHOR]

Humans and animals are exposed to mycotoxins naturally present in foods. Ochratoxin A (OTA), one of the most abundant and toxic mycotoxins, is ubiquitous in nature and harmful to humans and animals. In this study, we developed a rapid, simple, specific, and sensitive lateral-flow immunochromatographic assay for detection of OTA in 0.01 M phosphate-buffered saline solution (PBS) (pH 7.4) and in red wine. We produced sensitive and selective monoclonal antibody against OTA. Under optimized conditions, the cut-off limit of the test strip was 10 ng/mL OTA in 0.01 M PBS (pH 7.4) and in red wine. The results were obtained within 10 min. Therefore, our developed method is useful for the detection of OTA in red wine. [ABSTRACT FROM AUTHOR]

In this paper, we describe the development of a rapid, simple, specific, and sensitive immunochromatographic strip test based on an antibody-antigen reaction for detection of tulathromycin (TULA) in samples of 0.01 M PBS pH 7.4, pure milk and honey. The monoclonal antibodies specifically recognized the corresponding antigens produced in our laboratory. Under optimized conditions, the cut-off limits of the test strips for TULA in 0.01 M PBS pH 7.4 was found to be 2.5 ng/mL. Meanwhile, with simple preparation for detection in pure milk and honey samples, the cut-off limits for TULA were found to be 5 and 10 ng/mL, respectively. Each test can be evaluated in 5 min. In summary, this lateral-flow device provides a sensitive, effective, specific, and rapid method for detection of TULA residues in food matrix. [ABSTRACT FROM AUTHOR]

The presence of pesticide residues in crops is a significant public concern. Due to the large number of samples and pesticides, a reliable, simple, cost-effective, and high-throughput analytic method is required. In this study, we developed a gold nanoparticle (GNP) immunochromatographic assay (ICA) for the rapid detection of 6-benzylaminopurine (6-BA) residues in bean sprouts. A monoclonal antibody against 6-BA, having a half-maximum inhibition concentration of 2.25 ng/mL, was labeled with GNPs and fixed onto a glass fiber membrane to create a conjugate pad. Coating antigen and goat anti-mouse antibody were sprayed onto a nitrocellulose membrane to form the test line and control line, respectively. The visual limit of detection and cutoff limit of ICA were 10 and 80 ng/g in bean sprouts, respectively. The results of ICA were obtained within 10 min with the naked eye. Therefore, ICA is a rapid tool for the on-site screening and detection of 6-BA in bean sprouts. [ABSTRACT FROM AUTHOR]

Procaine (PRC) is a local anaesthetic used in the treatment of several disease related to ageing, asthma, and arthritis. In this study, we describe a rapid, sensitive, simple, and accurate method for the determination of PRC in milk, using an immunochromatographic test strip. For the immunochromatographic test, antigen (PRC-bovine serum albumin) and goat anti-mouse IgG were drawn onto a nitrocellulose membrane representing the control line and test line. The test was developed with a sensitive monoclonal antibody specific for PRC, generated by immunizing BALB/c mice with a well-characterized PRC- Keyhole limpet hemocyanin conjugate, produced in our laboratory. Under optimized conditions, the semi-quantitative test strip was able to detect PRC at concentrations down to 1 ng/mL in both 0.01 M phosphate buffer saline (pH 7.4) and milk samples. All results were obtained within 5 min. Our data indicate that the immunochromatographic assay is capable of sensitive, rapid, and specific on-site screening of PRC. [ABSTRACT FROM AUTHOR]

Clonidine (CLO) preferentially stimulates central α-2-adrenoceptors and causes both desirable and undesirable effects. Undesirable effects include sedation and withdrawal reactions, which occur as a sudden rise in arterial pressure, nervousness, agitation, and increased heart rate. An immunochromatographic test strip was developed for the rapid simultaneous detection of CLO and its cross-reactivity with apraclonidine (ACLO) in pig urine. The antigen CLO-OVA and goat anti-mouse IgG were attached to a nitrocellulose membrane as control line and test line. The cut-off limits of the test strips for CLO and ACLO were found to be 2.5 ng/mL in both 0.01 M PBS (pH 7.4) and pig urine. All the results were obtained within 5 min. The results revealed that the developed method is a sensitive, rapid, and simple tool for the detection of CLO and ACLO. [ABSTRACT FROM AUTHOR]