Bi/mZVI Combined with Citric Acid and Sodium Citrate to Mineralize Multiple Sulfa Antibiotics: Performance and Mechanism

The oxidative mineralization of sulfanilamide drugs (SAs) using micro-size zero-valent iron (mZVI) cooperated with a citric acid buffer solution was evaluated. In this study SM2, SMX, and SD could be removed at 66%, 89%, and 83%, respectively, in a 0.5% Bi/mZVI+CA+NaCA system within 2 h. Based on our analysis, the produced ·OH could be ascribed from the complexation between citrate iron (Fe(II)[Cit]−) and the generated H2O2 resulting from the activation of O2 on the mZVI surface in the Bi/mZVI+CA+NaCA system, further inducing the mineralization of antibiotics. The related possible degradation pathways were proposed. Two similar degradation pathways of SM2, SMX, and SD in the mixed liquid, including hydroxylation and SO2 extrusion, were solved. Meanwhile, there was an additional proposed degradation pathway for SMX to be degraded more effectively, as reflected in the opening of the N-O bond on the benzene ring. Therefore, this work provides an experimental basis and theoretical support for the efficient treatment of antibiotic wastewater in real industry by using an iron-based method.

Physicochemical Characterization and FTIR Spectroscopic Study of Pectin from Bombax ceiba (Bamta) Fruit

Pectin is a naturally occurring biopolymer which can be used for food and pharmaceutical applications. In this study the effect of temperature, time and pH on the yield, physicochemical characteristics of pectin extracted from Bombax ceiba fruits was investigated. The extraction of pectin was done using citric acid buffer followed by 96% alcohol precipitation. The optimum temperature, time and pH for the extraction of pectin were determined to be 85 °C, 90 min and 2.0, respectively. The yield of pectin under these optimum conditions was found to be 16.35%. The physicochemical properties determined under these optimum conditions were found to be; equivalent weight; 765.40 mg/mol, methoxyl content: 6.62%, anhydrouronic acid content; 65.25%, degree of esterification; 72.45%, moisture content; 1.30% and ashcontent; 0.60% for Bombax ceiba fruits extracted pectin, respectively. FTIR was also utilized for characterizing the pectins. Generally, the findings of the study showed that the pectin extracted from Bombax ceiba fruit can find industrial applications, especially in food processing and pharmaceutical industries.

Determination of Dipicolinic Acid in “Natto” by High-Performance Liquid Chromatography Coupled With Postcolumn Photoirradiation With Zinc Acetate

A system was developed for determining dipicolinic acid in “natto” using liquid chromatography with fluorometric detection. The compound was separated by reversed-phase chromatography using a mobile phase of 0.1 mol/L disodium hydrogen phosphate, 0.05 mol/L citric acid buffer (adjusted to pH 3.0) containing 3.0 mmol/L zinc acetate and 35 mmol/L perchloric acid. The compound in the column effluent was irradiated with ultraviolet light to produce fluorescence. This fluorescence was monitored at an excitation at 336 nm and an emission at 448 nm. The calibration curve for dipicolinic acid was observed to be linear in a range of 0.2 to 112 ng. The dipicolinic acid content of natto was 7.24 ± 0.54 mg/100 g (wet weight, mean ± standard deviation [SD], n = 6).

Determination of Aromatic Amines Released from Azo Dyes in Paper Packaging by Liquid Chromatography-Tandem Mass Spectrometry

An LC-tandem MS (LC–MS/MS) method for the determination of 21 kinds of carcinogenic aromatic amines released from azo dyes in food wrappers was used in this research. Sodium dithionite was added to a citric acid buffer medium to reduce and decompose possible azo dyes. The extract was analyzed after liquid–liquid extraction (LLE) and dispersive SPE (d-SPE). The conditions for chromatographic separation, mass spectrum, LLE, and d-SPE were optimized. Under optimal conditions, the LOD was in the range of 0.13–0.35 mg/kg and LOQ in the range of 0.38–1.05 mg/kg, with the addition of standard recoveries of most aromatic amines being ≥80% and RSDs ≤10%. The recoveries for 2,4-diaminotoluene and 2,4-diaminoanisole were significantly lower, being ≤40%. The method was successfully used to analyze 30 practical samples, and the results showed that it is user-friendly, with high sensitivity, rapid control, and low matrix interference.

An Immunonanosilver Surface-Enhnaced Resonance Raman Scattering Method for Determination of Human Chorionic Gonadotrophin

In pH 6.6 Na2HPO4-citric acid buffer solution and in the presence of KCl, the nanosilver-labeled rabbit anti-hCG (Ag-RAhCG) was aggregated un-specifically to the aggregations. Upon addition of rhodamine 6G (RhG) molecular probe, it adsorb on the surface of Ag-RAhCG aggregations that exhibited the strongest surface-enhnaced resonance Raman scattering (SERRS) peak at 613 cm-1. In the optimal condition, the decreased SERRS intensity responds linearly with the concentration of hCG over 0.05-1.75 µg/mL. Based on this, a new and simple SERRS method has been proposed for the determination of hCG in serum samples, with satisfactory results.

An Immunonanosilver Resonance Rayleigh Scattering Spectral Probe for Rapid Assay of Human Chorionic Gonadotrophin

In pH 6.6 Na2HPO4- citric acid buffer solution and in the presence of KCl, the immunoreaction between hCG and nanosilver-labeled anti-hCG took place, the immunonanosilver-complex was formed and deposited, caused the resonance Rayleigh scattering (RRS) intensity at 510 nm decreased. In the optimal condition, the decreased RRS intensity responds linearly with the concentration of hCG over 0.125-1.75 µg/mL. Based on this, a new and simple RRS method has been proposed for the determination of hCG in serum samples, with satisfactory results.

A New Resonance Rayleigh Scattering Assay for the Determination of Trace Hg(II) Using the Immunonanogold as Probe

Nanogold (NG) in size of 10 nm was prepared by the NaBH4 procedure. A new ligand 6-mercaptonicotinic acid (MNA) was used to couple both methylmercury chloride (CH3HgCl) and carrier protein to obtain an immunogen, it was immunized BALB/C mice, and the spleen cells of immunized mice were fused with myeloma cells. The monoclonal antibody (mAb) against mercury (II) ions was produced by the hybridoma technique. The mAb was labeled the NG to prepare an immunonanogold (ING) probe for Hg(II). In pH 5.4 Na2HPO4-citric acid buffer solution and under the condition of ultrasonic irradiation, the ING particles were aggregated un-specifically to form big particles that exhibited a strong resonance Rayleigh scattering (RRS) peak at 580 nm. When the Hg(II) was added, the specific immunoreaction of ING-Hg(II) take place, and the ING-Hg(II) immunocomplex dispersed in the solution that caused the RRS intensity decreasing linearly at 580 nm. The decreased intensity was linear to Hg(II) concentration in the range of 0.025-10 μmol/L, with a detection limit of 1.1 nmol/L Hg(II).