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Abstract

A rapid and simple ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) method was developed and validated for simultaneous determination of six analytes from the Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. leaves (ESL) in beagle dog plasma for the first time, including 3-O-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside-29-hydroxy oleanolic acid, 3-O-β-d-glucopyranosyl-(1→2)-α-l-arabinopyranoside-29-hydroxy oleanolic acid, 3-O-β-d-glucopyranosyl-(1→2)-α-l-arabinopyranosyl-30-norlean-12,20 (29) –dien-28-olic acid, ciwujianoside E, guaianin N, and eleutheroside K. The chromatographic separation was performed using an ACQUITY UPLC BEH C18 column (2.1 × 100 mm, 1.7 μm) using a gradient elution way with a mobile phase of acetonitrile-water containing 0.1% formic acid. Analytes were detected on a triple-quadrupole mass spectrometer equipped with an electrospray ionization (ESI) source with multiple reaction monitoring (MRM) mode. Calibration curves were all linear (r ≥ 0.9933) over the concentration range. The mean extraction recoveries and matrix effect of analytes and I.S. were ranged from 80.26% to 98.32% and from 91.27% to 111.67%, respectively. The intra-day and inter-day precision were ranged from 2.20% to 14.81%, and the accuracy range was 1.60–14.60%. The analytical method was successfully applied for the pharmacokinetic characteristics of the six analytes in beagle plasma after oral administration of ESL extracts. The T 1/2 of six analytes was more than 3.09 ± 0.78 h.

Open access

Abstract

Epilepsy is one of the most prevalent neurological conditions and antiepileptic drugs are the mainstay of epilepsy treatment. High variation in pharmacokinetic profiles of several antiepileptic drugs highlights the importance of therapeutic drug monitoring to estimate pharmacokinetic properties and consequently individualize drug posology. In this work, a simple, rapid and robust liquid chromatography-tandem mass spectrometry method was developed for simultaneous quantification of carbamazepine and its metabolite carbamazepine-10,11-epoxide, gabapentin, levetiracetam, lamotrigine, oxcarbazepine and its metabolite mono-hydroxy-derivative metabolite, phenytoin, topiramate, and valproic acid in human plasma for therapeutic drug monitoring. d 6-Levetiracetam, d 4-gabapentin and d 6-valproic acid were used as internal standards. After addition of internal standards along with two-step protein precipitation and dilution sample preparation, plasma samples were analyzed on a C18 column using a gradient elution in 5 min without interference. The calibration curves were linear over a 100-fold concentration range, with determination coefficients (r 2) greater than 0.99 for all analytes. The limit of quantification was 0.5 μg mL−1 (0.1 μg mL−1 for oxcarbazepine, 2 μg mL−1 for levetiracetam, and 10 μg mL−1 for valproic acid) with precision and accuracy ranging from 3% to 9% and from 94% to 112%, respectively. Intra- and inter-day precision and accuracy values were within 15% at low, medium and high quality control levels. No significant matrix effect was observed in the normal, hemolyzed, lipemic, and hyperbilirubin blood samples. This method was successfully used in the identification and quantitation of antiepileptic drugs in patients undergoing mono- or polytherapy for epilepsy.

Open access

Abstract

A rapid, selective, and precise high performance thin layer chromatographic method was developed and validated for the simultaneous analysis of paracetamol, caffeine, phenylephrine and chlorpheniramine in tablets. The chromatographic analysis was carried out on glass plates pre-coated with silica gel 60 F254 as a stationary phase. The optimized mobile phase was methanol : n-butanol : toluene : acetic acid (8:6:4:0.2 v/v). TLC chamber of 10 × 20 cm was used with saturation time of 15 min. The retardation factor (RF) for chlorpheniramine, phenylephrine, caffeine and paracetamol was found to be 0.15 ± 0.02, 0.29 ± 0.02, 0.50 ± 0.02, 0.68 ± 0.02 respectively. Detection was carried out at 212 nm. Validation study was done following ICH Q2 (R1) guideline. The regression data for the calibration plots showed good linear relationship with R 2 = 0.997 over the concentration range of 300–1,500 ng band−1 for caffeine, R 2 = 0.996 over the concentration range of 100–500 ng band−1 for phenylephrine, R 2 = 0.996 over the concentration range of 200–600 ng band−1 for chlorpheniramine, R 2 = 0.998 over the concentration range of 400–2,400 ng band−1 for paracetamol. The method was validated for precision, accuracy and recovery. Minimum detectable amounts were found to be 304.9 ng band−1, 87.88 ng band−1, 117.18 ng band−1 and 143.06 ng band−1 for caffeine, phenylephrine, chlorpheniramine, and paracetamol respectively while the limit of quantification was found to be 923.95 ng band−1, 266.32 ng band−1, 355.11 ng band−1, and 433.53 ng band−1 in the same order. The method was successfully applied to analyze two marketed tablets in a selective and reproducible manner.

Open access

Egy köles tájfajta műtrágya-reakciójának vizsgálata

Examination of the reaction to fertilization of regional millet variety

Agrokémia és Talajtan
Authors: Zsembeli Zsadány, Sinka Lúcia, Tüdősné Budai Júlia, Kovács Györgyi, Tuba Géza, and Zsembeli József

Kutatómunkák általános célja olyan kísérletek végzése, amelyek feltárják az adott régióban perspektivikusan termeszthető fajták, illetve tájfajták optimális műtrágyázási igényeit. Tanulmányunkban a Karcagon nemesített és fenntartott ’Maxi’ köles tájfajta tápanyagreakciójának vizsgálatából származó eredményeinket mutatjuk be a módosított Országos Műtrágyázási Tartamkísérlet (OMTK) 2017. évi és az annak figyelembevételével 2021-ben beállított Műtrágyázási Kísérleti Kert (MKK) adatai alapján. A kísérleteket Karcagon, a MATE Karcagi Kutatóintézetben, egy mélyben szolonyeces réti csernozjom talajon állítottuk be. 2017-ben a módosított OMTK kezelései 4 nitrogén (40, 80, 120, 160 kg ha 1), 4 foszfor (0, 40, 80, 100 kg ha 1) és 3 kálium (0, 60, 90 kg ha 1) dózis kombinációjából adódtak, illetve volt egy műtrágyázás nélküli abszolút kontroll. 2021-ben az MKK kezelései 3 nitrogén (40, 80, 120 kg ha 1), 3 foszfor (0, 40, 80 kg ha 1) és 2 kálium (0, 60 kg ha 1) dózis kombinációját foglalták magukba, illetve mindegyik parcella felére növénykondicionáló szert juttatunk ki. A termesztett növény mindkét évben a karcagi nemesítésű ’Maxi’ kölesfajta volt. A különböző kezeléscsoportok termésre gyakorolt hatásának statisztikai értékelését egytényezős varianciaanalízissel végeztük el. Mindkét vizsgálati évben a 80 kg ha 1 hatóanyag mennyiségben kijuttatott nitrogén műtrágyázás bizonyult a leginkább megfelelőnek. A magas foszfor dózisok a legtöbb esetben termésdepresszióhoz vezettek. Eredményeink alapján még a közepes – jó kálium ellátottságú karcagi talajokon is hasznos lehet a kálium kijuttatása, bár a káliumtrágyázás termésre gyakorolt hatását a varianciaanalízis nem igazolta. Az Algomel PUSH szerrel végzett növénykondicionálás statisztikailag is igazolhatóan, mintegy 10%-kal növelte a termés nagyságát. Kutatómunkánk folytatásával pontosabban meghatározható lesz számos tájfajta tápanyagreakciója és fajtaspecifikus, a helyi agroökológiai viszonyokat is figyelembe vevő tápanyag dózisok és kombinációk ajánlhatók a gazdálkodóknak.

The general objective of our research is to carry out experiments that are suitable to reveal the optimal fertilization demand of regionally bred or potentially producible crop varieties for a specific region. In our recent study, the results gained from the examination of the nutrient reaction of the regional millet variety ‘Maxi’ bred and maintained in Karcag are introduced based on the data originating from the modified Long-term National Fertilization Experiments (OMTK) in 2017 and from the Fertilization Experimental Garden (MKK) established at Karcag in 2021. Both experiments were set up in the MATE Research Institute of Karcag on a meadow chernozem soil salty in the deeper layers. In 2017, there were 4 nitrogen (40, 80, 120, 160 kg ha−1), 4 phosphorus (0, 40, 80, 100 kg ha−1), and 3 potassium (0, 60, 90 kg ha−1) dosage combinations applied and one unfertilized absolute control in the OMTK trial. In 2021, in the MKK experiment, treatments involved 3 nitrogen (40, 80, 120 kg ha−1), 3 phosphorus (0, 40, 80 kg ha−1), and 2 potassium (0, 60 kg ha−1) dosage combinations, furthermore, on half of the plots a plant conditioner was sprayed. Millet variety ‘Maxi’ bred at Karcag was the indicator crop in both years. For the statistical analysis of the effect of the various treatment groups on yields, One-way ANOVA tests were used. We considered the 80 kg ha−1 nitrogen substance dose the most suitable in both years. High dosage of phosphorus application resulted in yield depression in most of the cases. Based on our results, potassium fertilization can be effective even on the soils of Karcag with medium to good potassium supplies, though the analysis of variance did not justify the effect of K-fertilization on yields. The 10% yields increase due to plant conditioning with Algomel PUSH was statistically proven. By continuing or research, the reaction to fertilization of several regional crop varieties can be determined more precisely, and variety-specific nutrient doses and combinations can be determined and suggested to the local famers taking the regional agri-ecological conditions into consideration.

Open access
Acta Chromatographica
Authors: Hao-ran Dai, Ya-hui Hu, Jia-yi Long, Ying Xia, Hong-li Guo, Jing Xu, Xuan-sheng Ding, Jing Chen, Xiao-peng Lu, and Feng Chen

Abstract

Perampanel (PER) is the first clinically available selective antagonist of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor approved globally for the treatment of epilepsy. Studies have recently underlined the significant association between dose-exposure-effect-adverse events of PER in patients with epilepsy, so the therapeutic drug monitoring (TDM) of PER is critical in clinical practices, especially for pediatric patients with drug-resistant epilepsy. Due to several limits in previous published analytical methods, herein, we describe the development and validation of a novel liquid chromatography tandem mass spectrometry (LC-MS/MS) method for monitoring PER in human plasma samples. Protein precipitation method by acetonitrile containing PER-d5 as internal standard was applied for the sample clean-up. Formic acid (FA, 0.2 mM) in both aqueous water and acetonitrile were used as the mobile phases and the analyte was separated by an isocratic elution. Qualification and quantification were performed under positive electrospray ionization (ESI) mode using the m/z 350.3 → 219.1 and 355.3 → 220.0 ions pairs transitions for PER and PER-d5, respectively. Potential co-medicated anti-seizure medications (ASMs) have no interference to the analysis. Calibration curves were linear in the concentration range of 1.00–2,000 ng mL−1 for PER. The intra- and inter-batch precision, accuracy, recovery, dilution integrity, and stability of the method were all within the acceptable criteria and no matrix effect or carryover was found. This method was then successfully implemented on the TDM of PER in Chinese children with drug-resistant epilepsy. We firstly confirmed the apparent inter- and intra-individual PER concentration variabilities and potential drug-drug interactions between PER and several concomitant ASMs occurred in Chinese pediatric patients, which were also in line with previous studies in patients of other race.

Open access

Abstract

Gluten-free (GF) breads are often described with low quality, rapidly staling, dry mouthfeel and crumbling texture attributes. In lack of recent texture profile data on commercially available, preservative-free, freshly-baked GF bread, this study aimed to compare different types of GF products with their wheat-based counterparts during a 4-day-long storage test. Texture analysis data showed that GF loaves performed better than or comparable to the wheat-based ones in hardness, springiness and cohesiveness. Among sensorial properties mouth-feel, softness and aroma were evaluated as significantly better or similar for GF versus wheat-based products. GF cob had a saltier taste, which reduced the flavour experience. Both the texture results of the storage test and sensory data showed that the quality of GF bread products improved in recent years; they stayed comparable with their wheat-based counterparts even during a 4-day-long storage period.

Open access

The selectivity of the separation of five antihistamines has been investigated by TLC on silica gel 60 F254 and on aluminium oxide 60 F254 with a variety of mobile phases in horizontal chambers. The best separation selectivity and retention differences for the drugs on the two types of plate were obtained with the mobile phases chloroform–ethyl acetate, 1 + 1 (v/v), ethyl acetate, and butan-2-one–toluene, 7 + 3 (v/v).

The plates were visualized by illumination at l = 254 nm and by reaction with different reagents. The greatest detection sensitivity – 0.06 mg for cetirizine, 0.1 mg for chloropyramine, and 0.2 mg for antazoline, doxylamine, and ketotifene – was obtained by spraying with potassium iodoplatinate reagent.

Restricted access
JPC - Journal of Planar Chromatography - Modern TLC
Authors: Alka J.M. Horvat, Jasenka Živko-Babić, Danijela Ivanković, Sandra Babić, and Marija Kaštelan-Macan

Knowledge of the composition of an incorporated alloy is a precondition for avoiding polymetallism in subsequent prosthetic treatment, or detection of the cause of an allergic reaction attributed to a metallic component of the prosthesis restoration. The method proposed in this paper can be a very useful means of determining the presence of Ni–Cr or Co–Cr dental alloys, and, especially, beryllium in Ni–Cr alloys which, despite its toxicity, gives the alloy desirable properties. Nickel is also a well-known allergen. This paper reports an analytical procedure for detection and identification of cobalt-and nickel-based dental alloy components. The method involves anodic sampling, and separation and identification of the components by thin-layer chromatography on precoated microcrystalline cellulose layers. Computer-assisted optimization was used to choose the mobile-phase composition. Excellent detection and identification of nickel, chromium, cobalt, molybdenum, and beryllium, on the basis of different RF values and spot colors, was achieved after anodic sampling in-situ.

Microanodic dissolution of dental alloys enables intra-oral, in-situ, and almost non-destructive sampling of a permanent prosthesis restoration.

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The object of this study was determination of the content and composition of the essential oil of the fruits of three varieties of stalk celery – Helios, Zefir, and Orient. We also investigated hexane extracts obtained from the fruits of two varieties of stalk celery – Helios and Zefir. The essential oils and the extracts were examined by TLC and GC–MS.

Analysis showed the presence of terpene (mono- and sesquiterpene) and non-terpene (phthalide) fractions in the oils and extracts investigated. The combined amount of limonene, α- and β-pinene and myrcene in the monoterpene fraction of the essential oils ranged from 79.1 to 82.9%. The amount of the sesquiterpene fraction (α-and β-selinene) was from 15.7% to 18.8%. The phthalide fraction (3-n-butylphthalide, dehydrosedanolide, and sedanolide) was found in trace amounts. The amounts of these fractions in the hexane extracts ranged from 40.2 to 43.6% for the monoterpene fraction, from 19.4 to 20.7% for the sesquiterpene fraction, and from 35.7 to 37.7% for the phthalide fraction.

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The conditions used for TLC and HPTLC analysis of catechins have been optimized. Chemically modified stationary phases (HPTLC CN, HPTLC NH2, and HPTLC RP-18W) were used for qualitative examination of polyphenol fractions obtained by an SPE–RP 18 method from Uncaria tomentosa bark. Although the best separation of catechin from epicatechin was achieved on octadecyl plates, silica gel plates are good enough for preliminary investigations of crude plant extracts.

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