Preparation and Characteristic Identification of Monoclonal Antibody Against Sulfamethazine

Two artificial antigens were synthesized successfully by diazotizing method, sulfamethazine（SM2）-human serum albumin （HSA） was used for the immunogen, and SM2-ovalbumin（OVA） was used for the coating antigen. The coupled reaction was successful by confirmation of the ultraviolet scanning spectrometer, and the conjugation ratio of SM2 with HSA and OVA was 9：1 and 15：1, respectively. Using cell-fusion and limiting dilution method to reclone 5 times to get 3 hybridoma strains, which could stably secret monoclonal antibody （Mab）, named CBT, BC4 and BB12. The subtype of BC4 Mab was IgG1 and chain, the molecular weight was 162 ku, the numbers of chromosomal were about 90, the affinity constant was 6.1 × 10^12 M^-1. No cross reactivity was seen between the Mab and the other 4 sulfonamides, as well as the 2 carries proteins. The Mab antibody had excellent stability.

Design and Synthesis of Novel 5-Sulfoxide-substituted Pyrazolo[5,1-d][1,2,3,5]tetrazin-4(3H)ones

A series of novel 5-sulfoxide-substituted pyrazolo[5,1-d] [1,2,3,5]tetrazin-4（3H）ones 4a-j were designed and efficiently synthesized via a diazotization of 5-amine-3-methylsulfinyl- 1H-pyrazole, followed by cycloaddition with aryl isocyanate. A possible reaction mechanism is outlined and discussed. These new compounds exhibit some biological activity as preliminary bioassay indicated. Their structures were confirmed with ^1H NMR, IR and elemental analysis.

Synthesis and Crystal Structure of 5-Diazo-4-ethoxycarbonyl-3-methylthio Pyrazol

The crystal of the title compound, 5-diazo-4-ethoxycarbonyl-3-methylthio pyrazole, has been prepared and determined by X-ray diffraction. The crystal belongs to the monoclinic system, space group C2/c with a = 29.174(8), b = 4.7592(12), c = 15.956(4) ? b = 117.632(4), C7H8N4O2S, Mr = 212.23, V = 1962.7(9) ?, Z = 8, Dx = 1.436 g/cm3, S = 1.000, m(MoKa) = 0.31 mm-1, T = 298(2) K, F(000) = 880, R = 0.0658 and wR = 0.1741 for 1091 independent reflections with I ≥ 2s(I). The crystal of the title compound is formed with p-p interactions through electrostatic attractions. Moreover, no HSO4- exists in the crystal structure. Therefore, only diazo pyrazole was obtained rather than either diazonium salt of the corresponding pyrazole or diazoaminopyrazole when 5-amino-4-ethoxycarbonyl-3-methylthio pyrazole was diazotized with sodium nitrite, catalyzed by sulfuric acid at 0 ℃.

An Efficient and Green Route to Synthesize Azo Compounds through Methyl Nitrite

A clean preparation of aryl diazonium ions using methyl nitrite is described. Further reaction of the aryl diazonium ions with substituted benzenamine, substituted phenol and nathphol in deferent kinds of diazotization has been developed. In order to improve the water-solubility of the products, azo coupling reactions of sodium sulfanilate hydrochloride diazonium ions were also performed. The procedures are easy operations, environmentally benign conditions and high yields of the products with potential use as azo-dyes and pigments. Furthermore, no nitrous acid is produced during the diazotization which avoided the formation of dark decomposition products of the corresponding aromatic amine. Proposed mechanism is presented according to our procedure.

Green-Emitting Carbon Dots as Fluorescent Probe for Nitrite Detection

Nitrite(NO_(2)_(-))is a well-known inorganic pollutant in food and environment that can trigger severe environmental and healthy problems.Consequently,establishing accurate NO_(2)_(-)detection method is very important for food security,environment monitoring and human health.In this work,green fluorescent carbon dots(CDs)with a high fluorescence quantum yield(QY)of 36.13%are prepared for NO_(2)_(-)detection.The CDs are prepared by one-pot hydrothermal carbonization and polymerization of acriflavine.After carbonization,the anti-photobleaching property of CDs significantly enhanced compared to acriflavine.Under acidic conditions,the added of NO_(2)_(-)selectively induces the aggregation and fluorescence quenching of CDs.A good fluorescence linearity response in the range of 50 nM to 10μM can be developed for NO_(2)_(-)quantitative analysis,with a detection limit of 11.6 nM.Owing to the diazotization reaction of NO_(2)_(-)and the phenylamine groups on the surface of CDs,this method shows excellent selectivity compared to common ions and amino acids.Furthermore,the proposed method shows favorable results in the detection of real water and Cantonese style sausage sample.This study provides a simple and e fficient method for NO_(2)_(-)detection in food and environment.