This study was aimed at employing response surface methodology (RSM) for optimization of process variables and identifying optimal conditions for the adsorption of bromate (BrO3-) from contaminated water using multi-walled carbon nanotubes, based on iron hydr(oxide), Fe-CNTs nanocomposite. Fifteen experimental runs were conducted in batch mode to study the effect of individual as well as interactive process variables, i.e., pH, BrO3- initial concentration, and adsorbent dose, on the removal of BrO3- using Box-Behnken design (BBD) of RSM. The coefficient of determination (R²) at 98.34% indicated a good agreement between actual and predicted values. The main effect and contour plot were drawn to obtain the independent and interactive effect of operational variables on BrO3- uptake. A process optimization curve was drawn to determine the optimum operating conditions that lead to a desirable response. The optimum conditions for BrO3- adsorption using Fe-CNTs nanocomposite were found to be pH 2.0, initial BrO3- concentration of 10.0 mg/L, and adsorbent dose of 0.010 g per 50 mL solution.

ABSTRACT: Two analytical methods were developed, one utilizing sensitive UPLC-MS/MS method while other being the spectrophotometric method exploiting the Dushman reaction. Both methods were validated based on ICH guidelines and were successfully applied to quantitate the drug in marketed formulation. UPLC-MS/MS method responded linearly in the range of 1.6 µgmL-1-6.4 µgmL-1 while spectrophotometric procedure followed the Beer’s law in the concentration range of 30-100 µgmL-1. UPLC-MS/MS has been found to have a limit of quantitation of 0.97 µgmL-1 while spectrophotometric method was found to quantitate 14.00 µgmL-1 correctly with high precision. Both the methods showed an excellent recovery of 99.36%-100.91% (% RSD 1.05-1.73) and 98.64%-99.73% (%RSD 0.67-1.68) for UPLC-MS/MS and spectrophotometric, respectively.

ABSTRACT UPLC-MS analytical procedure has been established for the determination of adrenaline in marketed formulation and in the pure form. The detection of the adrenaline was executed considering positive electrospray ionization (ESI) and selected ion reaction (SIR) modes. Chromatographic separation was achieved using ACQUITY UPLC BEH C column (100 mm × 2.1 mm, 1.7 μm particles size) using a binary mobile phase mixture of methanol and water (50:50). The mobile phase was set to flow at the rate of 0.3 ml min−1. The run time time for adrenaline was as short as 1.5 minutes. Linearity was found to be over the concentration range of 1μg ml−1 – 6μg ml−1. An excellent recovery of 100.18 % – 100.68 % was achieved using this procedure. The standard deviation ranged from 0.014 – 0.118 in intra-day studies and 0.016 – 0.096 in case of inter-day studies. The procedure's quantitation limit was 0.76μg ml−1 and detection limit was 0.25 μg ml−1. The method was successfully applied to determine adrenaline in drug formulations. In order to get the information about the stability of adrenaline in various environments forced degradation studies were conducted and the characterization of the stressed samples were performed using mass spectrometry.

A rapid, simple, sensitive LC-MS/MS method involving a least pretreatment process has been proposed for the quantitative assessment of venlafaxine (VEN) and O-desmethyl venlafaxine (ODV) using cetirizine as an internal standard. The method was validated over the range of 1.03 ng/mL to 453.50 ng/mL (venlafaxine) and 1.32 ng/mL to 585.21 ng/mL (O-desmethyl venlafaxine). The lowest limit of quantification for venlafaxine and O-desmethyl venlafaxine was found to be 1.03 ng/mL and 1.32 ng/mL, respectively. The solid phase extraction procedure provided reliable and reproducible recoveries of the drug as well as its active metabolite with no interference at their retention time. The recovery for all analyzed drugs was found to be in the range of 72.55% to 74.75%. The result indicates that the developed procedure could be considered suitable for carry out simultaneous preclinical pharmacokinetics studies for VEN and ODV.