A new, rapid, and specific reversed phase high-performance liquid chromatographic (RP-HPLC) method involving precolumn derivatization with benzoyl chloride was developed and validated for the estimation of γ-aminobutyric acid (GABA) in rat brain tissue preparations. The derivatization product of GABA was identified by melting point, infrared, and proton nuclear magnetic resonance (1H NMR) spectroscopy to be n-benzoyl GABA. Various parameters which influenced derivatization and elusion were optimized. The chromatographic system consisted of C-18 column with ultraviolet (UV)—photodiode array detection ranging from 210 to 400 nm. Elution with an isocratic mobile phase consisting of 0.025 M disodium hydrogen phosphate buffer—methanol (65:35, v/v; pH 6) at a flow rate of 1 mL min−1 yielded sharp and specific peak of n-benzoyl GABA within 7 min. The method was validated with respect to the linearity, accuracy, precision, sensitivity, selectivity, and stability, wherein the benzoyl derivative of GABA showed stability for 2 months. The lower limit of detection was 0.5 nmol L−1. This novel derivatization procedure for the estimation of GABA with benzoyl chloride was also applied for rat brain tissue preparations that gave highly specific peak and good component recovery. The results show that the method for the determination of GABA by benzoylation using RP-HPLC has good linearity, accuracy, precision, sensitivity, and specificity and is simple and economical to perform.
, phenolic compounds were analyzed by a sensitive and selective ultra-performance liquid chromatography combined with photodiode-array detector–electrospray ion source–mass spectrometry (UPLC–PDA–ESI–MS) method in wheat varieties and their antioxidant
Instrumentation and Chromatographic Conditions
HPLC analyses were carried out on a Shimadzu Nexera UHPLC system comprising of a solvent delivery system of 2 pumps (LC-30 AD), an autoinjector (SIL-30 AC Auto Sampler), and a photo diode array (PDA
literature for simultaneous identification and quantification of LM, BM, and YM in fruit rinds of Garcinia species using a rapid ultra-high-performance liquid chromatography with photodiode array detection (UHPLC–PDA) method.
Earlier, Ji et al. [ 21
aim to develop validated ultra high-performance liquid chromatography coupled to PDA (UHPLC-PDA) with electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) method and implement it to quantify six major isoquinoline alkaloids in the roots
the above mention techniques, and was therefore used in the pharmacokinetic study of letrozole.
For determination of PLB, there are few validated reversed-phase HPLC with photodiode array detection (RP-HPLC–PDA) methods for determination of PLB
membrane syringe filter before injection into the UPLC system.
Identification of the chemical patterns and the analysis of the optimal experimental conditions was performed using a UPLC–photodiode array (PDA
The procedure involving water and water-methanol extraction, RP-HPLC-C18 column chromatography with PDA detection was developed for determination of cinnamic acid and benzoic acid derivatives in grapevine’s dietary supplements (LV, RW, VIN, VIC, and DK) available on the Polish market. Phenolic acids were analysed before and after acidic and basic hydrolysis and identified against standards. Totalamount of studied phenolic acids determined by HPLC-PDA was compared with total polyphenols content (TPC) by Folin-Ciocalteu method. The average content of studied phenolic acids (70.54±0.21; 122.95±0.49; 87.67±0.10; 132.21±0.24; 266.78 ±0.39, and 18.16±0.09 mg/100 g d.m. (dry mass) for LV, RW, VIN, VIC, DK, and WW, respectively) were higher than the TPC (1489.91±0.39, 1648.19±0.14, 1574.38±0.33, 1643.64±0.12, 1984.75±0.97, and 715.55±0.36 mg/100 g d.m. for LV, RW, VIN, VIC, DK, and WW, respectively). The new developed method was validated for specifi city, repeatability, and accuracy and can be suitable for routine quality and quantity analysis of dietary supplements containing grape vine (Vitis vinifera).
Rapid identification of known compounds, i.e., dereplication, has become a strategically important area for the natural-product chemists involved in bioprospecting of microbes for novel bioactive metabolites. Among microbial biodiversity, endophytic fungi represent an abundant and dependable source of structurally diverse bioactive metabolites. During the course of screening for antimicrobial secondary metabolites from endophytic fungi, an antimicrobial metabolite was identified from the ethyl acetate extract obtained from the culture broth of Xylaria sp., an endophytic fungus from Ficus pumila Linn. (Moraceae) that exhibited a broad spectrum of antimicrobial activity against human and phytopathogenic bacteria and fungi. Chemical investigation of the ethyl acetate fraction using thin-layer chromatography (TLC) bioautography and LC-hyphenated techniques led to the identification of a known benzoic acid derivative. Here, we describe the application of analytical strategies (TLC-bioautography) and hyphenated spectroscopic techniques (liquid chromatography-photodiode array detector-mass spectrometry [LC-PDA-MS]) for the dereplication of antimicrobial metabolites.
A simple, precise, rapid, and accurate liquid chromatography-mass spectrometry (LC-MS) compatible reversed phase high-performance liquid chromatography-photodiode array detection (RP-HPLC-PDA) method has been developed and validated for the estimation of oxcarbazepine (OXC) in bulk and tablet formulations. The chromatographic separation was achieved on Phenomenex C18 column (150 mm · 4.6 mm, 5.0 μm particle size) using the mobile phase comprising methanol-formic acid (0.02% v/v in water) in the ratio of 50:50 (v/v) at a flow rate of 1 mL min−1, and OXC was eluted at 6.4 min. Quantification and linearity were achieved at 229 nm over the concentration range of 10–50 μg mL−1, and the mean percentage of assay was found to be 100.03. The method was validated for specificity, linearity, accuracy, precision, limit of detection (LOD), limit of quantification (LOQ), stability, and robustness as per the International Conference on Harmonisation (ICH) guidelines and it is suitable to be employed in quality control.