M.Z.A. Rafiquee

Rapid and sensitive method for analysis of nitrate in meat samples using ultra performance liquid chromatography-mass spectrometry.

A sensitive and selective ultra performance liquid chromatography-mass spectrometric method has been developed for the quantitative analysis of nitrate in meat samples. Selected ion reaction (SIR) mode was adopted to identify and quantify the nitrate. Chromatographic analyses were performed on a BEH C-18 column with a mobile phase consisting of a surfactant (Cetylpyridinium chloride) and acetonitrile in equal ratio (50/50, v/v) at a flow rate of 0.4 mL min(-1). The limit of detection and limit of quantitation of the developed method was found to be 0.0599 and 0.1817 mg kg(-1), respectively. The linearity of the proposed method was checked in the concentration range of 0.5-10 mg kg(-1) with an excellent correlation coefficient (r) of 0.997. The recovery of the nitrate in the meat samples were in the range of 98.02-98.99%.

High-Throughput UPLC–MS Method for the Determination of N-Acetyl-l-Cysteine: Application in Tissue Distribution Study in Wistar Rats

N-Acetylcysteine (NAC) is the N-acetyl derivative of the amino acid l-cysteine and is extensively used as a medicine to treat a variety of diseases. High-throughput ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS) method has been developed for the quantitative assessment of N-acetyl-l-cysteine. The method was further applied to study the distribution of the intraperitoneal injected drug into different tissues and plasma of Wistar rats, including liver, kidney, heart, lungs and spleen. The drug was having highest concentration in plasma and liver followed by kidney, lungs, heart and spleen. Method validation studies suggested being linear in the range of 1-15 µg mL(-1) for liver, kidney, heart, lungs and spleen and 1-120 µg mL(-1) for the plasma. The limit of detection and limit of quantitation were found to be 0.20 and 0.66 µg mL(-1), respectively. The recovery studies suggested that in all the cases, the obtained recovery was in the range of 98.51-101.88%. Our analyses provide a validated UPLC-MS method for the determination of NAC and its successful application for the analysis in plasma and tissues obtained from Wistar rats.

Permanganate Oxidation of Sulfadiazine: Analytical Method Development and Kinetic Study

A multi-disciplinary approach has been made in this article where, the oxidation reaction of permanganate and sulfadiazine has been used to develop analytical method to quantitate the drug and the second part is the kinetic study of the oxidation reaction. The estimation of the drug is made at 602 nm. The developed method has been validated as per the international conference on harmonization (ICH) guidelines. The regression treatment of the linearity data yielded the linear regression equation A=0.00786+0.0184 C. Limit of detection and limit of quantitation was found to be 2.33 and 7.065, respectively. Since, the reaction proceeded such that the absorbance increased with increase in time, kinetic study of the reaction was performed. The kinetic parameters were performed at 602 nm. The reaction obeyed pseudo first-order kinetics in [alkaline KMnO4] and fractional order in [sulfadiazine]. The oxidation reaction was carried out at varied temperatures viz. 25, 30, 35, 40 and 45 (±0.1°C). On the basis of the observed results, mechanism of the reaction has been proposed. Activation parameters such as energy of activation, enthalpy, entropy and Gibbs free energy were determined and found to be 8.73 (kJ mol-1), 77.57 (kJ mol-1), 173 (JK-1 mol-1), 25.99 (kJ mol-1) respectively.

Alkaline hydrolysis of Co(Asn)2 (Asn = l-asparagine)

AbstractThe kinetics of alkaline hydrolysis of Co(Asn)2, yielding Co(OH)2, NH3 and aspartic acid, have been studied spectrophotometrically, and the effects of CoII and NaOH concentrations on the reaction rate determined. The rate increases with increasing [NaOH], whereas variation of [CoII] has no significant effect. The kinetics of NH3 evolution conform to the rate law:

INFLUENCE OF CATIONIC AND ANIONIC MICELLES ON THE REACTION OF NINHYDRIN WITH DIFFERENT AMINO ACIDS : A KINETIC STUDY

{\text{d[NH}}_{\text{3}} {\text{]/d}}t = k_1^\prime k_2^\prime [{\text{OH}}^ - ][{\text{Co(Asn)}}_{\text{2}} ]/(k_{ - 1}^\prime + k_2^\prime )

HIGH THROUGHPUT ULTRA PERFORMANCE LIQUID CHROMATOGRAPHY - MASS SPECTROMETRIC METHOD FOR DETERMINATION OF ADRENALINE AND CHARACTERIZATION OF ITS STRESS DEGRADATION PRODUCTS: A MECHANISTIC APPROACH

It is proposed that the reaction proceeds through formation of a dianionic tetrahedral intermediate.