Abstract
A precise, accurate, selective and sensitive capillary electrophoresis method using a diode array detector was developed for the first time for the determination of both scutellarein (SLN) ...and caffeic acid (CAA) in prepared Abelia triflora extract. Electrophoretic analysis was performed using a background electrolyte solution consisting of borax buffer (40 mM, pH 9.2) and a 200-nm detection wavelength. This method was fully validated according to The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines. The method was linear in the concentration range 2.5-100 μg/mL and it allowed the determination of both compounds with high degree of recovery (%Er < 2%) and intra-day and inter-day precision (relative standard deviation values <2%) and method robustness was also assessed by the low values of %RSD < 2% obtained after small deliberate changes in the method parameters. The contents of SLN and CAA were calculated using both the external standard and standard addition methods. Analysis of the ethyl acetate fraction of A. triflora revealed that SLN and CAA were found in concentrations of 0.46 mg/g and 2.10 mg/g, respectively, in the ethyl acetate fraction and 0.29 and 1.32 mg%, respectively, in the dry plant leaves.
Parabens are widely used as preservatives in thousands of consumer’s products including, cosmetics, pharmaceutical products, and foodstuffs. Concern in regards to the safety of parabens has been ...raised where parabens have been classified as “Endocrine disrupting compounds” with potential link to many tumor types. Despite their wide spread, the occurrence of parabens in foodstuffs available in the Saudi market has not been studied until now. In this work, an HPLC-PDA method was developed and validated for the screening of parabens’ residues in different categories of Ready-to-eat foodstuffs collected from the Saudi market. These categories include: cereals, meat, fish, dairy product, bean products, fruits, vegetables, cookies and snacks, beverages, condiments, and others. Chromatographic analysis of the selected parabens (Methyl paraben MeP, ethyl paraben EtP, propyl paraben PrP, butyl paraben BuP, and isobutyl paraben isoBuP) was performed on Symmetry® C-18 Colum (4.6 × 75 mm, 3.5 μm) with methanol/water (57:43, v/v) as the mobile phase and using simply methanol for sample preparation. The proposed method was fully validated with regards to linearity, limits of detection (LOD) and of quantitation (LOQ), accuracy and precision, extraction recovery, and specificity. Matrix-based calibration curves were linear in the range 0.025–500 μg/g (MeP, EtP), 0.05–500 μg/g (PrP), and 0.125–1250 μg/g (IsoBuP, BuP) with LOQ 0.025 μg/g for MeP, EtP, 0.05 μg/g for PrP, 0.125 μg/g for both BuP and isoBuP. The method was successfully applied for quantitative screening of the five parabens in different Ready-to-eat foodstuffs (n = 215) collected from the Saudi market. The total parabens content was determined and was related to the food category and to the packaging material. The highest paraben content was found in cereals and condiments. The type of the packaging material did not have a significant effect on the paraben content among all food categories. Moreover, the estimated daily intake of parabens among the Saudi adults was calculated and it was found to have an average of 2000 μg/kgbw/day.
In this work, an HPLC-DAD method was developed for the residual analysis of some estrogens such as estrone (E1), 17-β estradiol (E2), estriol (E3), natural estrogens, and 17-α ethinylestradiol (E4), ...an exoestrogen, in meat samples of different categories (chicken,
= 155, beef,
= 124, sheep,
= 122, and camels,
= 40), collected from the Saudi Market. Although banned, the use of E4 as a growth promoter in the black market is still encountered. Symmetry C18 column (3.5 µm, 4.6 mm × 150 mm) was used with a mobile phase consisting of 50% aqueous acetonitrile. Protein precipitation with acetonitrile was used for the sample preparation. The method was fully validated, as per the ICH guidelines, in the concentration ranges of 0.35–125 µg/g (E1, E2), 0.188–125 µg/g (E3), and 0.188–450 µg/g (E4). The method allowed the trace analysis of estrogens with LOD values of 0.094 (E3, E4) and 0.126 µg/g (E1, E2), and LOQ values of 0.188 (E3, E4) and 0.350 µg/g (E1, E2). The analyzed samples contained different levels of estrogens. Within the same category, processed products contained the highest levels of E4, while the internal organs contained the least estrogen content. Finally, the estimated daily intake, µg/kg bw/day, of estrogens through the consumption of meat-based food products was calculated.
Capillary electrophoresis with a diode array detector was employed for the determination of luteolin and apigenin in plant extracts. The experimental factors affecting the elution of the analytes ...were carefully optimized. The final analysis was achieved utilizing a fused silica capillary (58 cm effective length, 75 μm ID) and a background electrolyte solution consisting of borax buffer (20 mM, pH 10.0) and methanol (90: 10, v/v) with a 23 kV driving voltage and detection at 210 nm. The method was fully validated as per the guidelines of the International Conference on Harmonization for Analytical Procedures. The relationship between peak area and concentration was linear between 3 and 800 μg/mL for both compounds with detection limits of 1.05 for luteolin and 0.53 μg/mL for apigenin. The method was employed for the determination of the analytes in extracts of thyme and parsley. Both compounds were resolved from interfering peaks that were present in the extracts. Recovery studies were performed by fortifying the extracts with standards and demonstrated good accuracy with recovery values between 97.29 and 104.88% for luteolin and 96.89 and 105.18% for apigenin. Thyme and parsley were shown to contain high concentrations of luteolin and apigenin.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
A stability-indicating capillary electrophoresis method coupled to a diode array detector (DAD) was developed and validated for the simultaneous determination of emtricitabine (FTC) and tenofovir ...disoproxil fumarate (TDF) in combined tablets. This proposed method utilized a fused silica capillary (effective length, 62 cm; internal diameter ID, 75 microm) and a background electrolyte (BGE) consisting of phosphate solution (pH 9.5, 50 mM). The separation was achieved at a voltage of 25 kV and a temperature of 21 degreesC using paracetamol as an internal standard. The described method was linear over the range of 5-200 microg/mL for both drugs (r = 0.9992). Intra- and inter-day relative standard deviation (RSD) (n = 9) was 0.41%. The limits of detection for FTC and TDF were 1.25 and 1.00 microg/mL, respectively. The average percentage recoveries of FTC and TDF from their tablet formulations were 99.66 + or - 0.73 and 99.48 + or - 0.33, respectively. The two drugs were subjected to thermal, photolytic, hydrolytic, and oxidative stress conditions, and then the stressed samples were analyzed by the proposed method. Degradation products produced as a result of stress studies did not interfere with the detection of FTC and TDF. The assay can thus be considered stability indicating. Keywords: CE-DAD, stability indicating, emtricitabine, tenofovir disoproxil fumarate
Delonix elata (L.) Gamble (Fabaceae) is an important, traditionally used plant in Saudi Arabia. It is used to relieve rheumatic pain, flatulence and the seeds are employed as purgatives. The aim of ...the present study was to isolate chemical constituents of the n-butanol fraction (BF) of D. elata and to find out, by capillary electrophoresis (CE), percentage of rutin present in this BF. Three quercetin glycosides and one kaempferol rutinoside were isolated from the BF of aerial parts of D. elata; namely, Quercetin 3-O-rutinoside-7-O-glucoside (1), Quercetin 3,7-diglucoside (2), Quercetin 3-O-rutinoside (RUT) (3) and Kaempferol 3-O-rutinoside (4). Rutin, an active constituent has been reported to possess good pharmacological as well as therapeutic potentials. A sensitive and rapid procedure for quantitative determination of RUT by capillary electrophoresis was developed and its content was found to be 7.349 mg/gm, relative to n-butanol fraction and 18.373 mg%, relative to the dry powder of D. elata. The method could be recommended for approval and use in the pharmaceutical and food industries.
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