Browse Our Chemical Engineering Journals

Chemical engineering is an engineering branch that deals with the chemical production and manufacture of products that undergo chemical processes. This includes equipment design, creating systems and processes to refine raw material, as well as mixing, compounding, and processing chemicals to create products.

Chemistry and Chemical Engineering

You are looking at 1 - 10 of 33,916 items for

  • Refine by Access: All Content x
Clear All

Abstract

Monitoring medications in biological fluids is an essential aspect of patient care, particularly in cases of altered mental status where accurate diagnosis, effective treatment, and even forensic examinations are crucial. In this study, a new approach combining hydrophobic-deep-eutectic and solvent-bar-microextraction (HDE-SBME) followed by a high-performance liquid chromatography-diode array detector (HPLC-DAD) was developed for the simultaneous determination of desipramine, clomipramine, as antidepressant and carbamazepine as antiepileptic agents in untreated human urine and plasma samples. The HDE solvents, synthesized using various ratios of menthol and fatty acids, were utilized in the SBME setups. Computational methods were employed to predict the structure and modes of interaction between HDE and the chosen analytes. Central composite design methodology (CCD) was used for multivariate optimization of the effects of different parameters influencing the extraction efficiency of the proposed method. Under optimized experimental conditions, the calibration graph of the spiked selected drugs in urine and plasma samples demonstrated excellent linearity (R 2 ≥ 0.994), with limits of detection/quantification below 0.60/2.02 μg L−1. The extraction recoveries achieved were 88–97%, and the repeatability/reproducibility (RSD%, n = 5) was less than 6.12/7.57. The proposed method was successfully applied to determine selected drugs in patients' urine and plasma samples. The proposed method detects three drugs in patients' urine and plasma samples without using toxic volatile organic solvents. The proposed microextraction technique exhibited a confident sensitivity, feasible operation, and simplicity compared with other published methods. Thus, it can be considered a promising method for monitoring the therapeutic levels of specific antidepressant and antiepileptic drugs in urine and plasma samples.

Open access

Abstract

The primary objective of the present inquiry is to formulate a sustainable method employing Reverse Phase-High Performance Liquid Chromatography (RP-HPLC) for determination of Amlodipine (AM) and Irbesartan (IRB) simultaneously, compounds commonly prescribed for hypertension treatment. Existing literature underscores the absence of a comprehensive method in this regard. This research endeavors to align with the tenets of green chemistry by seamlessly integrating Analytical Quality by Design (AQbD) with RP-HPLC, replacing environmentally hazardous chemical modifiers with eco-friendly solvents. Identifying the critical variables as the 70% ethanol level and flow rate, a central composite design is applied for optimization. The separation is achieved utilizing a Phenomenex Luna column (C 18 , 250 mm × 4.6 mm i.d, 5 μm) with a mobile phase comprising ethanol and 0.1 % o-phosphoric acid in a 70:30 v/v ratio, flowing at 0.8 mL min−1, and detection wavelength of 242 nm. Green assessment methodologies are implemented to gauge the adherence of the proposed RP-HPLC method to eco-friendly principles while ensuring efficiency in chromatographic performance. The current developed method is rapid with retention time of 2.3 and 3.3 min for AM and IRB respectively and having a wide linear range from 55 to 130 μg mL−1, which makes the suitable for the accurate quantification of AM and IRB simultaneously in bulk and tablet dosage form, there by minimize environmental impact by providing a conscientious choice for the routine analysis which is achieved through the amalgamation of AQbD with a sustainable approach.

Open access

Abstract

SZJ-1207 is a natural product extracted from Stephanotis mucronata (Blanco) Merr which has significant antidepressant effects in various depression mouse models, without obvious acute toxicity or sedative-hypnotic side effects. The aim of this study was to preliminarily clarify the pharmacokinetic characteristics of SZJ-1207 in rats after a single intragastric and intravenous administration. In this study, sensitive and reliable UPLC-MS/MS quantification methods were established and then successfully applied to the pharmacokinetic study of SZJ-1207 in rats. The linear range of SZJ-1207 were 0.5–400 ng mL−1 in plasma, feaces, bile and 20–4,000 ng mL−1 in urine, respectively (r > 0.99). All methods met the requirements of ICH M10. The results of pharmaconetic study showed that Cmax, AUC(0-t) and AUC(0-∞) had linear relationships with the administered doses in the range of 0.5–4.5 mg kg−1. There was a significant gender difference in the AUC (0-t) of 0.5 and 1.5 mg kg−1 and Cmax of 1.5 mg kg−1 after ig (P < 0.05). The excretion rates of SZJ-1207 were 8.46 ± 4.82% in feces, 1.89 ± 1.08% in urine, and 0.179 ± 0.118% in bile. The oral absolute bioavailability of SZJ-1207 was calculated as 64.64%.

Open access
Acta Chromatographica
Authors:
Qing Jia
,
Ziyue Wang
,
Shuqian Wang
,
Shunjun Ma
,
Xueqi Qiao
,
Xueli Huang
,
Xianqin Wang
,
Congcong Wen
, and
Xia-yin Zhu

Abstract

Objective

The levels of fraxetin, fraxin, and dimethylfraxetin in rat plasma to be measured using an ultra-performance liquid chromatography tandem mass-spectrometry (UPLC–MS/MS) technique and applied to their pharmacokinetics and bioavailability.

Methods

The protein precipitation technique was applied to the plasma preparation using acetonitrile and methanol (9:1, v/v). At a flow rate of 0.4 mL min−1, the elution time was 6 min. The mobile phase consisted of acetonitrile-water with 0.1% formic acid, and the chromatographic column was UPLC HSS T3 (50 mm × 2.1 mm, 1.8 μm). Quantitative analysis was conducted using multiple reaction monitoring (MRM) mode and detection was performed using electrospray ionization (ESI) positive ion mode. In each group, six rats were treated with fraxetin, fraxin, and dimethylfraxetin either orally (5 mg kg−1) or intravenously (1 mg kg−1).

Results

The calibration curves showed good linearity in the range of 2–4,000 ng mL−1, where r was greater than 0.99. The bioavailability of dimethylfraxetin, fraxin, and fraxetin was determinated to be 19.7, 1.4, and 6.0%.

Conclusion

The established UPLC-MS/MS method for determining the levels of these three compounds in rat plasma was successfully applied to the pharmacokinetics of dimethylfraxetin, fraxin, and fraxetin, and the bioavailability was calculated.

Open access

Abstract

The article evaluates how well the goals of the European Green Deal are justified, especially considering the risks to energy and food security arising from the conflict between Russia and Ukraine. We agree with the objectives of the European Green Agreement as a whole, but whether some of the objectives which feature in the EASAC study can be achieved by 2030 is questionable, and the description of the tools necessary to achieve the objectives is incomplete. Among other things, there is hardly any mention of the role played by precision farming with digitalization, which is a revolutionary change from an ecological and economic point of view, in reducing the use of synthetic inputs, in regenerating the original state of the soil, in reducing GHG emissions, thus in increasing biodiversity, and at the same time in intensifying production, and finally in expanding the application of biotechnology. We examine these areas in our analysis. Some of the objectives of the EASAC study to be achieved by 2030 are subject to debate, and the description of the information and communication conditions necessary to achieve the objectives is incomplete. The IoT (Internet of Things) responds to global and local challenges: it integrates the precision technologies, WSNs (Wireless Sensor Networks), artificial intelligence, mobile field (Smart Small Robots) and remote data loggers (UAVs: Unmanned Air Vehicles and satellites), Big Data, and cloud computing. Consequently, decision support is increasingly developing into unmanned decision making. IoT (Internet of Things) is the basis of “Farm to Fork” and “Lab to Field” monitoring approaches.

This article evaluates the implementation of European Green Agreement objectives in light of energy and food security risks arising from the Russia-Ukraine conflict. While overall support for the agreement exists, the feasibility of certain EASAC study objectives by 2030 is called into question due to insufficient tools specifications. Notably absent is the emphasis on precision farming with digitalization, which is a transformative ecological and economic practice. Our analyses look into its function in reducing synthetic inputs, soil regeneration, GHG emission reduction, biodiversity enhancement, production intensification, and biotechnology development. Debates surround EASAC study objectives for 2030, despite limited information and communication restrictions. The Internet of Things (IoT) arises as a solution, combining precision technology, WSNs (wireless sensor networks), AI (artificial intelligence), smart small robots, UAVs (unmanned aerial vehicles), satellites, big data, and cloud computing. As a result, decision support turns toward unmanned decision-making, with IoT laying the groundwork for “Farm to Fork” and “Lab to Field” monitoring systems.

Open access

The use of organic fertilization is declining in Hungary due to the sharp fall of livestock stand since the middle of the 1980s. Most farmers are forced to use solely chemical crop enhancers. A bifactorial small plot experiment was carried out between 10 May 2023 and 19 October 2023 in Keszthely, in order to examine the effects of farmyard manure (M), green manure (GM) and stem residues (SR) on the nutrient uptake and nitrogen utilization efficiencies of maize at equidistantly increasing (0–70–140–210–280 kg N ha–1) nitrogen doses. The relationship between some vegetative traits (dry biomass weight, Leaf Area Index (LAI)) and yield, furthermore leaf relative water content (RWC) was also examined. According to the results, organic fertilizer substitution significantly increased the N content both in whole plant and grain samples of NPK+M and NPK+GM+SR treatments, compared to the chemically fertilized control (NPK). In case of P and K only slight differences were observed. Whole plant K contents of NPK+M were significantly higher than in the other treatments (P = 0.045; P = 0,005), furthermore P contents in grain samples were significantly higher in NPK+M (P = 0.004) and NPK+GM+SR (P = 0.05) than in control. Harvest index (HI [%]) of NPK+M and NPK+GM+SR were 1.06 and 1.05 times higher than in NPK. Depending on the treatment, P0023 maize hybrid absorbed 58.7–74.64% of total N uptake in the grain (HIN%), and the utilization of 1 kg N fertilizer for the extra yield above the yield of the individual control was 0.39–1.38 kg (AREN). Significant positive correlations were observed between dry biomass weight and yield (NPK: r = 0.937, P = 0.019; NPK+M: r = 0.971, P = 0.006; NPK+GM+SR: r = 0.88, P = 0.049), furthermore LAI and yield (NPK: r = 0.9, P = 0.037; NPK+M: r = 0.983, P = 0.003; NPK+GM+SR: r = 0.784, P = 0.117). Highest RWC values – which may be related to better soil aggregate stability – were measured in NPK+GM+SR treatment, therefore there may be a great potential in this treatment among drought conditions. The effect of organic amendments is particularly noticeable with smaller nitrogen doses so they should be used to reduce inorganic fertilizer application and the resulting environmental risks.

Open access

Abstract

A simple, fast and selective analytical method has been developed for the simultaneous determination of allantoin and D-panthenol in cosmetic products containing Aloe vera extracts. The proposed method depends on reversed-phase liquid chromatography with isocratic flow profile of the mobile phase composed of acetonitrile–10 mM phosphoric acid (pH 2.5) (85:15, v/v), with a C18 column at 30 °C. The analytes were detected with UV–vis. detector at 210 nm. The injection volume was 20 μL. The linearity ranges were found to be 0.2–20 and 0.1–10 μg mL−1 for allantoin and D-panthenol, respectively. LOD values were found to be 0.07 μg mL−1 and 0.03 μg mL−1, LOQ values were found to be 0.2 and 0.1 μg mL−1 for allantoin and D-panthenol, respectively. No interference was observed from concomitants. The developed method was applied to the analysis of 10 different type cosmetic products. It is foreseen that the method will be able to be used in order to carry out routine analysis, quality control and standardization in cosmetic products containing allantoin and D-panthenol.

Open access

Abstract

A simple, rapid, and green high-performance liquid chromatography-mass spectrometry (HPLC-MS) method was developed for determination of tauroursodeoxycholic acid (TUDCA), taurocholic acid (TCA), and taurochenodeoxycholic acid (TCDCA) in bio-transformed Jindanfen (BTJDF), which is obtained from chicken bile through a bioconversion process. The sample was prepared using water. The HPLC separation was operated on a poroshell 120 EC-C18 column with a 2.0 min gradient elution procedure. Detection was performed on a single quadrupole mass spectrometer in negative mode with selected ion monitoring mode (SIM). This developed HPLC-MS method presented good linearity (r > 0.997) and sensitivity (limit of quantification, 30.0–80.0 pg) for three analytes. The relative standard deviations (RSDs) for precision, repeatability, and stability were all below 3.00%. The matrix effects and average recoveries of three analytes were 91.2–97.9% (RSDs < 1.50%) and 95.4–103% (RSDs < 3.00%), respectively. The average contents of TUDCA, TCA, and TCDCA in ten batches of samples were 33.8, 13.2, and 20.5%, respectively. Finally, the greenness of the developed method was validated by Analytical Eco-Scale and Complex-GAPI. The developed method was proved to be an eco-friendly, effective, and reliable approach for assaying the three cholic acids in BTJDF, which is help to improve the quality evaluation level of the BTJDF industry.

Open access

Abstract

The current technologies for substandard and counterfeit drug detection are either too expensive for low-resource settings or only provide qualitative or semi-quantitative results. GPHF minilab™ is one of them based on thin layer chromatography(TLC) principles with a semi-quantitative capability by visual observation of the spot area and intensity for medicine quality analysis. Thus, its use as a quality control tool for pharmaceutical products has limitations as spot area and intensity visual observation by the naked eye highly varies from analyst to analyst. As such, in this study, the semi-quantitative technique has been transferred to a quantitative approach by capturing the developed TLC plate image using an Android-based mobile phone inside a simple carton box. Then, the spot area was quantified using justTLC software. The quantitative results were compared with the-high performance liquid chromatography (HPLC) method as the golden standard. Accordingly, linearity was observed in the assayed range (80–120% label claim), and the correlation coefficients found were (R 2 = 0.958, 0.997, 0.941, and 0.956 for Albendazole, Mebendazole, Artemether, and Lumefantrine, respectively.). The values are satisfactory. The %RSDs found were less than 2% for all drugs [intraday (n = 6) (RSD = 1.17, 1.61, 1.87, and 1.64), and interday (n = 18) (RSD = 1.16, 0.72, 1.12, and 1.18) for Artemether, Lumefantrine, Mebendazole, and Albendazole, respectively]. Moreover, comparisons of results obtained from the sophisticated CAMAG UV cabinet (R 2 =0.991, 0.971, 0.946, and 0.967) and the developed simple carton box (R 2 = 0.958, 0.997, 0.941, and 0.956) for Albendazole, Mebendazole, Artemether, and Lumefantrine, respectively. The values are comparable and reveal the accuracy of the method. Robustness testings' that were performed under different altered conditions revealed the robustness of the method (RSD less than 2% for all factors). Additionally the deviations from the golden HPLC results were on average −8.62% for albendazole, −3.79% for artemether, and −4.52% for lumefantrine samples. The developed method shows a satisfactory performance capability to utilize the GPHF minilab™ as a quantitative technique for medicine quality control purposes. It will be a very useful tool in a resource-limited setting. The target method profile, which encompasses a simple, low-cost, linear, precise, robust, accurate, and quantitative GPHF minilab™ system, was obtained for Albendazole, Mebendazole, and Arthemeter lumefantine combinations (Co-artem). The proposed method was successfully applied to analyze the content of the marketed medicines in the above mentioned tablets and offered acceptable deviations from the golden HPLC method. Automation of quantitative GPHF minilab™ was highly recommended to enhance the appropriateness and use of this system.

Open access