Ternary Metal (W-Ni-Sr) Oxide@Polypyrrole Nanotubes: A New Frontier in the Electrochemical Detection of Promethazine Hydrochloride (PMHC) Shilpa Purushothama, Sirisha Subbareddy, Santhosh Arehalli Shivamurthy, Sandeep Shadakshari, Shruthi Chinnakurli Dwarakanath, and Venkata Narayana Palakollu American Chemical Society (ACS) Promethazine hydrochloride (PMHC) is a vital drug that is used as an anticholinergic, antipsychotic, antihistaminic, analgesic, sedative, and neuroleptic. However, the overdosage of PMHC also causes reproductive variations, cardiac changes, hypotension, and endocrinal variations. Hence, the detection of PMHC is crucial. Therefore, in this work an electrochemical method for the detection of PMHC is reported. The fabrication for the modified electrode is built with tungsten (W), nickel (N), and strontium (S) ternary oxide (tWNSO). To the best of our knowledge, this tWNSO ternary oxide preparation is reported for the first time in the literature. The prepared ternary oxide is deposited on the polypyrrole nanotubes, and this nanocomposite that is formed is confirmed by various physical characterizations like XRD, SEM, TEM, UV-vis spectroscopy, FTIR spectroscopy, and also DFT studies for PMHC. Thus, the nanocomposite obtained is used as a working electrode for the detection of PMHC. The fabricated tWNSO/PPyNTs/GCE has an effective surface area of 0.0436 cm2. Also, no fouling was observed. The limit of detection of the analyte PMHC is 3.66 nM, the limit of quantification is 11.10 nM, and the sensitivity of the fabricated electrode in identifying the analyte is found to be 20.10 μA μM-1 cm-2. Thus, the modified working electrode effectively detects the analyte PMHC while demonstrating excellent stability and reproducibility.
The development of a GC-FID method for indirect quantification of chloroacetyl chloride, a potential genotoxic impurity, in chlordiazepoxide hydrochloride drug substance Srinivas Birudukota, Bhaskar Mangalapu, Ramesha Andagar Ramakrishn, Swagata Halder, and Venkata Narayana Palakollu Open Science Publishers LLP This study presents an innovative gas chromatographic-flame ionization detection (GC-FID) method, developed and validated in accordance with The International Council for Harmonisation (ICH) guidelines, for the quantitative analysis of chloroacetyl chloride, a potentially genotoxic impurity, in chlordiazepoxide hydrochloride active pharmaceutical ingredient. Due to the reactive and genotoxic nature of chloroacetyl chloride, precise quantification is imperative in the active pharmaceutical ingredient. The proposed method involves the conversion of chloroacetyl chloride into methyl 2-chloroacetate (MCA), enabling indirect quantification via a GC-FID approach employing a DB wax column. The validated GC-FID method displays exceptional features, such as remarkable linearity, ranging from 0.38 to 1.8 ppm with a correlation coefficient of 0.9998, as well as low detection and quantification limits of 0.19 and 0.38 ppm, and the method is specific without interference. The precision of the method expressed as the % RSD was 0.53%. The sample recovery ranging from 97.3% to 101.5%, confirms the method’s accuracy. Furthermore, three different batches of chlordiazepoxide hydrochloride underwent evaluation using this method. In conclusion, this method offers a highly sensitive approach for the precise quantification of chloroacetyl chloride in chlordiazepoxide hydrochloride drug substance, thereby ensuring compliance with the stringent safety standards of the pharmaceutical industry.
Electrochemical immunosensing of tumor markers Venkata Narayana Palakollu, Y. Veera Manohara Reddy, Mehdihasan I. Shekh, S.V. Prabhakar Vattikuti, Jaesool Shim, and Rajshekhar Karpoormath Elsevier BV
Tuning the Surface Functionality of Fe<inf>3</inf>O<inf>4</inf> for Sensitive and Selective Detection of Heavy Metal Ions Manjunatha Kumara K. S., D. H. Nagaraju, Zhoveta Yhobu, Nayan Kumar H. N., Srinivasa Budagumpi, Shubhankar Kumar Bose, Shivakumar P., and Venkata Narayana Palakollu MDPI AG The functionalization of materials for ultrasensitive detection of heavy metal ions (HMIs) in the environment is crucial. Herewith, we have functionalized inexpensive and environmentally friendly Fe3O4 nanoparticles with D-valine (Fe3O4–D–Val) by a simple co-precipitation synthetic approach characterized by XRD, FE-SEM, and FTIR spectroscopy. The Fe3O4–D–Val sensor was used for the ultrasensitive detection of Cd+2, Pb+2, and Cu+2 in water samples. This sensor shows a very low detection limit of 11.29, 4.59, and 20.07 nM for Cd+2, Pb+2, and Cu+2, respectively. The detection limits are much lower than the values suggested by the world health Organization. The real water samples were also analyzed using the developed sensor.
A versatile and ultrasensitive electrochemical sensing platform for detection of chlorpromazine based on nitrogen-doped carbon dots/cuprous oxide composite Venkata Narayana Palakollu, Rajshekhar Karpoormath, Lei Wang, Jiao-Ning Tang, and Chen Liu MDPI AG The excessive intake of chlorpromazine (CPZ) adversely affects human health profoundly, leading to a series of severe diseases such as hepatomegaly and dyskinesia. The rapid and precise detection of CPZ in real samples is of great significance for its effective surveillance. Herein, a versatile and sensitive electrochemical sensor was developed for the detection of antipsychotic drug CPZ based on a Nafion (Nf)-supported nitrogen-doped carbon dots/cuprous oxide (N-CDs/Cu2O) composite. The as-synthesized N-CDs/Cu2O composite was systematically characterized using various physicochemical techniques. The developed composite-based sensor displayed excellent performance towards CPZ determination in a dynamic linear range of 0.001–230 µM with the detection limit of 25 nM. Remarkably, the developed sensor displayed good performance in terms of sensitivity and selectivity. Furthermore, good anti-interference properties toward CPZ determination were attained despite the presence of highly concentrated interfering compounds. Therefore, this composite could be a notable potential modifier to enhance electrocatalytic activity onto the surface of the electrode. Finally, N-CDs/Cu2O/Nf-based sensor was effectively applied for quantification of CPZ in human urine and pharmaceutical formulation samples.
A Simple, Efficient and Ultrasensitive Gold Nanourchin Based Electrochemical Sensor for the Determination of an Antimalarial Drug: Mefloquine Tirivashe Elton Chiwunze, Neeta Bachheti Thapliyal, Venkata Narayana Palakollu, and Rajshekhar Karpoormath Wiley Mefloquine (MQ) is a quinoline based antimalarial drug, which is potent against multiple drug-resistant Plasmodium falciparum. It is widely prescribed for the prophylactic treatment of malaria. Due to extensive usage of MQ, constant monitoring of the drug level in human body is of paramount importancein order to ensure that optimum drug exposure is achieved. The present work describes a gold nanourchins (AuNUs) based electrochemical sensor for the determination of MQ.AuNUs were synthesized via seed-mediated method and characterized using ultraviolet-visible spectroscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy, zeta-sizer and electrochemical techniques (electrochemical impedance spectroscopy and cyclic voltammetry). Fabrication of the sensor was done by drop-coating the synthesized AuNUs onto a glassy carbon electrode. The fabricated sensor exhibited enhanced voltammetric response, which was attributed to the excellent conductivity and high surface area of AuNUs. Under optimum square wave voltammetric conditions, the sensor displayed two linear response ranges (from 2.0×10−9 to 1.0×10−6 M and from 1.0×10−6 to 1.0×10−3 M) with a detection limit of 1.4 nM. The electrode demonstrated good reproducibility, stability and selectivity over common interferents. The utility of the sensor was successfully assessed for quantification of the drug in pharmaceutical preparation and spiked human urine sample. Thus, the present study demonstrates a promising approach for determination of MQ with practical utility in quality control and clinical analysis.
Development, Characterization and Application of a Carbon-Based Nanomaterial Composite as an Electrochemical Sensor for Monitoring Natural Antioxidant (Gallic Acid) in Beverages Palla Gopal, Tukiakula Madhusudana Reddy, and Venkata Narayana Palakollu Wiley Gallic acid (GA) is an important organic acid, found in many natural plants and in food beverages. Here in, we have developed a chemical sensor for the monitoring of GA in wine, green tea and fruit juices. The oxidation of GA was found to be an irreversible process and the corresponding mechanism was proposed. The effect of pH on the oxidation behavior was studied and pH-6.0 was selected as an optimum pH. Based on the scan rate results a linear relation was observed between the square root of scan rate and peak currents for GA, confirming the oxidation of GA as a diffusion controlled process. The kinetic parameters such as diffusion coefficient, heterogeneous rate constant and charge transfer coefficient values were determined. The limit of detection (LOD) and quantification (LOQ) values were calculated as 4.39 × 10-7 M and 1.46 × 10-6 M. The repeatability, reproducibility and stability of the developed sensor were examined and the results confirmed that the developed sensor was in superior in condition. Finally, the practical application of the developed sensor was scrutinized for the quantitative estimation of GA in wine, green tea and fruit juices.