One of the powerful treatment processes for the removal of dyes from aqueous solutions is adsorption method. In this study, removal of Acid Fuchsin dye from aqueous solutions has been studied by using Red Mud (RM) waste material after its modification with laccase from Russulaceae (Lactariusvolemus). Laccase was purified by using saturated precipitate (NH4 )2 SO4 , DEAE-cellulose and immobilized on red mud. Batch adsorption experiments have been performed as a function of pH, contact time, temperature, and adsorbent dosage. The Freundlich equation was found to have the highest value of correlation coefficient compared with the Langmuir model. In addition, pseudo-first-order and pseudo-second order models were used to study the kinetics of Acid Fuchsin dye adsorption onto RM and laccase modified-RM. It was proved that adsorption process undergoes pseudo-second-order kinetic by the high value of correlation coefficient. Thermodynamic parameters including the Gibbs free energy, enthalpy and entropy changes indicated that the adsorption of Acid Fuchsin dye onto laccase modified-red mud was feasible, spontaneous and endothermic. The results show that the laccase modified red mud can be used for the treatment of aqueous solutions as an alternative low cost adsorbent.

A simple, precise and accurate reversed phase high performance liquid chromatography (RP-HPLC) method was developed and validated for identification and simultaneous estimation of calcium gluconate and calcium phospholactate in a tablet dosage form. Detection and quantitation were performed by a Shimadzu Nexera LC-30AD system. Separation of the two analytes was achieved within 5 minutes by using Inertsil C18-3 column (4.6 mm x 150 mm, 5µm) and isocratic elution of aqueous solution of 1% (v/v) phosphoric acid and methanol by (90: 10, v/v) ratio at a flow rate of 1.0 mL/min. Detection was monitored at 210 nm. The linearity for calcium gluconate was in the range of 1.92-2.88mg/ mL with correlation coefficient of 0.9982 and linearity for calcium phospholactate was in the range of 2-3mg/ mL, with correlation coefficient of 0.9981, respectively. Stability indicating capability was established by forced degradation experiments. The proposed method was validated for linearity, repeatability, accuracy, specificity, robustness, Limit of Detection (LOD) and Limit of Quantification (LOQ). The developed method was successfully applied in analysis of a tablet formula.

A simple High-Performance Liquid Chromatography (HPLC) method was developed and optimized for quantification of the two fat-soluble (D2 and D3) vitamins in milk matrix. The optimization procedure was developed through a Plackett-Burman design (PBD) and Small Composite Design (SCD) (Draper-Lin). The significant (p<0.05) factors found in PBD were HPLC-column temperature, flow rate, composition of mobile phases and percentage of Triton X-100, and these were optimized by means of a Draper–Lin design. The study revealed that optimal operating conditions were found to be 15ºC HPLC-column temperature, 100% methanol (MeOH) as mobile phases, 0.8 mL/min as flow rate, and 7.2% Triton X-100. The final HPLC analytical procedure was validated according to Horwitz function and from the AOAC Peer Verified Methods (PVM) program on the analyte level, exhibit good linearity (>0.99), sensitivity (0.56-2.54 μg/mL), precision (<10%), and accuracy (>90%). The method was developed in this study is suitable for the quantification of vitamins D2 and D3 in milk samples and can be used for quality control and may replace the present Mexican Normative methods that employ a large amount of solvent and that are aggressive in the sample treatment, with low recovery, precision, and sensitivity.

Peptides are most widely used in treating various life threatening diseases and peptide therapeutics are emerging in a fast pace in recent years. Recombinant peptides are in the sweet spot between small molecule drugs and large biotherapeutic proteins. Exenatide, a therapeutic synthetic peptide used in the treatment of Type 2 diabetes was originally developed by Amylin Pharmaceuticals and approved in April 2005, marketed in the name of “Byetta”. It is a 4.18 kDa peptide with an iso-electric point (pI) of 4.70, which was expressed in microbial system as a fusion protein with a molecular weight of 21.1 kDa. The fusion protein contains thioredoxin as a solubility tag in order to express in soluble form and His-tag as an affinity tag to ease in the purification process and also to reduce proteolytic effects. The recurrent problem faced with ion exchange chromatography was that the recombinant fusion protein typically eluted as an aggregate. Hence, an attempt was carried out to screen various mixed mode chromatography resins by taking advantage of its ability to bind through more than one type of interaction. This study outlines the purification of recombinant fusion protein using different mixed mode resins and also compares the purification efficiency in terms of purity with that of ion exchange and affinity chromatography. The main aim of the the study was to find an alternative to affinity chromatography capture step. The current screening study revealed that it is feasible to purify recombinant protein from E.coli using mixed mode chromatography as a comparable capture step. Mixed mode chromatograpy can be a powerful alternative to affinity chromatography in downstream processing of biotherapeutics.

A simple chromatographic experiment was performed using theoretically stable and inert bonded-phase silica gels and molecular interaction energy values were calculated using a molecular mechanics calculation to obtain a quantitative explanation of the Hydrophilic Interaction Liquid Chromatography (HILIC) retention mechanisms. We found that the polar groups of the analytes were in contact with the polar groups of bonded phases. The molecular interactions and the removable of the analytes from the bonded-phases depended on the properties of the eluent components used in the chromatographic experiment. The interactions can be quantitatively analyzed from the calculated hydrogen-bonding and electrostatic energy values.

In this work, we investigate the “click” nature of the reaction of hydrogen sulfide and methanethiol with ethyl propiolate, with the aim to investigate its potential for sampling of volatile thiols. The principal reaction products were stable Z-thioacrylates, while the reaction with methanethiol also gave a minor E-configured product, and the reaction with hydrogen sulfide Z,E- and Z,Z- dimers. The thioacrylates were separated using a narrow-bore C18-amide column and detected using a photodiode array detector at wavelengths around 300nm. When the sulphides were produced from their sodium-thiolate salts and flushed through a series of impingers, nearly 100% of the generated hydrogen sulfide reacted and was trapped in the first impinger, while approximately 70% of methanethiol was absorbed by reaction with ethyl-propiolate. Our data show that the reaction of thiols with propiolic acid derivatives has the potential for application in a device for sampling of airborne thiols.