Performance Liquid Chromatography-diode Array Detection Research Articles

Bioaccessibility of Apple Polyphenols from Peel and Flesh during Oral Digestion.

Health benefits of apple polyphenols for different chronic diseases are postulated. To exert bioactive properties, absorption into the body is required (bioavailability), which is strongly influenced by matrix release (bioaccessibility). For seven apple varieties, in vitro experiments with simulated saliva fluid (SSF) and ex vivo digestion with centrifuged human saliva were conducted. Polyphenol characterization (high-performance liquid chromatography-tandem mass spectrometry) and quantification (high performance liquid chromatography-diode array detection) was related to an aqueous methanolic extraction. A polyphenol release of 63-82% from flesh and 42-58% from peel was estimated. While hydroxycinnamic acid derivatives were released in total, a significant retention was observed for flavanes and flavones. In particular, procyanidins were retained with increasing molecular weight. The data reveal a considerable polyphenol release during the oral digestion; however, differences among the varieties as well as flesh and peel were obvious. Due to negligible differences between both digestion media, the data supported the use of SSF instead of human saliva in further experiments.

Polystichum braunii ameliorates airway inflammation by attenuation of inflammatory and oxidative stress biomarkers, and pulmonary edema by elevation of aquaporins in ovalbumin-induced allergic asthmatic mice.

Asthma is a chronic inflammation of pulmonary airways associated with bronchial hyper-responsiveness. The study was aimed to validate the folkloric use of Polystichum braunii (PB) against ovalbumin (OVA)-induced asthmatic and chemical characterization OF both extracts. Allergic asthma was developed by intraperitoneal sensitization with an OVA on days 1 and 14 followed by intranasal challenge. Mice were treated with PB methanolic (PBME) and aqueous extract (PBAE) orally at 600, 300, and 150mg/kg and using dexamethasone (2mg/kg) as standard from day 15 to 26. High performance liquid chromatography-diode array detector analysis revealed the presence of various bioactive compounds such as catechin, vanillic acid, and quercetin. The PBME and PBAE profoundly (p < 0.0001-0.05) declined immunoglobulin E level, lungs wet/dry weight ratio, and total and differential leukocyte count in blood and bronchial alveolar lavage fluid of treated mice in contrast to disease control. Histopathological examination showed profoundly decreased inflammatory cell infiltration and goblet cell hyperplasia in treated groups. Both extracts caused significant (p < 0.0001-0.05) diminution of IL-4, IL-5, IL-13, IL-6, IL-1β, TNF-α, and NF-κB and upregulation of aquaporins (1 and 5), which have led to the amelioration of pulmonary inflammation and attenuation of lung edema in treated mice. Both extracts profoundly (p < 0.0001-0.05) restored the activities of SOD, CAT, GSH and reduced the level of MDA dose dependently. Both extracts possessed significant anti-asthmatic action mainly PBME 600mg/kg might be due to phenols and flavonoids and could be used as a potential therapeutic option in the management of allergic asthma.

Determination of Antioxidant Activity of Different Extracts From Bark of Pinus spp. grown in Giresun (Turkey) Province – Phenolic analysis by RP-HPLC-DAD

This study aimed to investigate the phenolic compounds, total phenolic content, and antioxidant activities of Pinus sylvestris L. var hamata Steven, Pinus pinaster Aiton subsp. pinaster, and Pinus pinea L. bark extracts prepared with hot water. The phenolic composition and total phenolic content (TPC) of extracts were determined by Reversed Phase-High Performance Liquid Chromatography-Diode Array Detector (RP-HPLC-DAD) and Folin–Ciocâlteu method, respectively. The antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging and ferric ion (III) reducing / antioxidant power (FRAP) assays. Besides, the highest total phenolic content was detected in P. pinea bark extract [984.46±4.08 μg mL-1 gallic acid equivalent (GAE) and 1163.33±4.04 μg mL-1 catechin equivalent (CE)] and the lowest result was detected in P. sylvestris bark extract (361.53±3.52 μg mL-1 GAE and 427.26±4.17 μg mL-1 CE). Among the tested materials, the most abundant phenolic compounds in P. pinea bark extract were catechin (3.586±0.114 mg g-1) and taxifolin (1.866±0.096 mg g-1). According to the antioxidant results, P. pinea bark extract exhibited remarkable antioxidant activity than standard BHT and Trolox [SC50: 1.64310±0.00003 µg mL-1 for DPPH and 1428.75±5.62 µM Trolox Equivalent Antioxidant Capacity (TEAC) for FRAP]. The obtained results indicated that pine bark extracts can be used as an easily obtainable natural source of antioxidants for the food and pharmaceutical industry.

Impacto do método de secagem como pré-tratamento para extração de compostos bioativos do jambolão (Syzygium cumini (L.) Skeels)

Abstract Jambolan (Syzygium cumini (L.) Skeels) is an under-explored fruit rich in polyphenols, which are associated with health benefits, such as increasing resistance to oxidative stress, inflammatory processes and cardiovascular, and platelet functions. These polyphenols can be obtained by extraction, but an efficient standard method remains a challenge. In this context, this work evaluated the impact of different pretreatments on jambolans to obtain bioactive compounds by aqueous extraction. An Air Circulation Oven (ACO) and Lyophilization (LYO) were used as pretreatments. In addition, the influence of mass, temperature, cycle, and time parameters were studied in the extraction methods used: Percolated Solid-Liquid (PSL), Conventional Solid-Liquid (CSL), and solid-liquid assisted by ultrasound (USL). The extraction yield was from 7.3% (ACO) to 46.3% (LYO), both using the PSL method. In addition, eleven phenolic compounds and six anthocyanins were detected by High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD), in expressive amounts of catechin and cyaniding in the LYO sample and, these extracts showed higher concentrations of bioactive compounds. The CSL method was more efficient on ACO samples and PSL on LYO samples. LYO extracts showed higher concentrations of bioactive compounds. Therefore, the use of a drying pretreatment results in extracts with a high antioxidant potential for application in the food, cosmetic, and pharmaceutical markets.

Simultaneous Determination of Carvedilol and its Impurities in Tablets by High Performance Liquid Chromatography

This study aimed to develop a simple and fast reverse-phase high performance liquid chromatographydiode array detection method for the simultaneous determination of carvedilol and five impurities (A, B, C, D, E) in tablets. The separation was carried out by Zorbax Eclipse XDB-C8 (150×4.6 mm; 5 μm) column. Isocratic elution was carried out using a mobile phase mixture of acetonitrile and phosphate buffer pH 2 (containing 1.5 mM 1-heptanesulfonic acid) in the ratio of 43:57 (v/v); while the flow rate was maintained at 0.7 ml/min. The impurity E was detected at 220 nm, carvedilol and other impurities were detected at 240 nm by a photodiode array detector. The good linearity was obtained with correlation coefficients (r2) greater than 0.995 in the range of 0.01-1500 μg/ml for carvedilol, 0.04-3.0 μg/ml for impurity A and 0.1- 3.0 μg/ml for impurities B, C, D, E. Inter-day and intra-day accuracy and precision data were within the acceptable limits. This new method has satisfactory applications in the quality control of pharmaceuticals containing carvedilol.

Nickel(II) interactions with chlorophylls in solution: impact to degradation induced by UV-irradiation

Chlorophylls and metal substituted complexes of chlorophylls with known photosensitizing abilities can be used in many types of biological and solar energy applications; thus, it is important to analyze their basic properties when they are treated by visible light and/or UV radiation. Nickel(II) can replace central magnesium from chlorophyll (Chl) molecule to form a metal substituted, “central” Ni-Chl complex. So, the possible formation of nickel-chlorophyll complexes in 95% ethanol at 40 °C was studied by UHPLC-DAD chromatography (UltraHigh Performance Liquid Chromatography–Diode Array Detector). Nickel(II)-chlorophylls interactions in the reaction solutions at 40 °C lead not only to the formation of the Ni-related Chls, Ni-Chl complexes but several oxidation and demetalation products of chlorophylls. On the other hand, the influence of nickel(II) – chlorophyll interactions on chlorophylls solutions stability under continual UV-A, -B, and -C irradiation in 95% ethanol, was followed by UV-Vis spectrophotometry. Chlorophylls as well as their reaction solutions with nickel(II) undergo photochemical degradation obeying first- order kinetics. In general, the degradation is “energy-dependent”, i.e. proportional to the UV photons energy input. Chlorophylls are less stable than their reaction solutions with nickel(II), probably due to the higher stability of Ni-chlorophylls complexes, to all three subranges of UV- irradiation.

Establishment of Holistic Quality Control Methods for Nelumbinis Folium Containing Alkaloids and Flavonoids with Simple HPLC Conditions.

In this study, a positive charged C18 column was used to explore its performance in analysis of herbal medicines containing alkaloids and flavonoids with Nelumbinis Folium (NF) as an example. A chromatographic fingerprint analysis method was established by high performance liquid chromatography-diode array detector with commonly used 0.1% formic acid as mobile phase additive and this method could simultaneously detect both alkaloids and flavonoids with good peak shape. It is noted that the HPLC conditions were directly applied in the HPLC-ESI-Orbitrap-MS/MS analysis, and 12 common peaks were identified. In the quantification method of nuciferine, compared with common C18 column, good performance was observed, including sharp and symmetric peak shape of nuciferine, and no obvious retention time shift in chromatogram. The fingerprint method and quantification method of nuciferine and quercetin-3-O-glucuronic acid could be readily utilized as quality control methods for NF and its related preparations.

Exploring sol–gel zwitterionic fabric phase sorptive extraction sorbent as a new multi-mode platform for the extraction and preconcentration of triazine herbicides from juice samples

Triazine herbicides are a class of common pesticides which are widely used to control the weeds in many agricultural crops. Although many studies have described methodologies for the determination of triazine herbicides in aqueous samples, the attention given to agricultural crops and their products is far more limited. In this study, a novel sol–gel zwitterionic multi-mode fabric phase sorptive extraction (FPSE) platform was developed for the matrix clean-up, extraction and preconcentration of five triazine herbicides from fruit juice samples prior to their determination by high performance liquid chromatography-diode array detection (HPLC-DAD). The novel zwitterionic multi-mode sorbent was characterized and its performance for fruit juice analysis was evaluated. Compared to other sol–gel sorbents, the novel zwitterionic sorbent helped cleaning all the acidic interferences from fruit juices. The herein reported FPSE protocol was optimized and validated. Under optimum conditions, the FPSE method showed good accuracy, precision and sensitivity. The limits of detection and limits of quantification for all analytes were 0.15 ng mL−1 and 0.50 ng mL−1, respectively. The enhancement factors of this method ranged between 36.7 and 51.8. The relative standard deviation for intra-day precision was below 5.6% and for inter-day precision was below 8.8%. Finally, the proposed FPSE-HPLC-DAD method was successfully employed for the analysis of various fruit juice samples.

Development and Validation of an Analytical Method for Betanine and Isobetanine in Processed Food Products Labeled with Beet Red

Red beet (Beta vulgaris L.) is a root vegetable and a popular functional food ingredient of dark red-purple appearance due largely to betacyanins, principally betanine (75-95%) and its isomer, isobetanine (15-45%). This study developed an analytical method for beet red in terms of betanine and isobetanine in processed food products labeled with beet red as a food additive. High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) was used with a C18 column. Linearity, limit of detection (LOD), limit of quantitation (LOQ), accuracy, precision and uncertainty in measurement were calculated for method validation. Matrix-matched calibration was applied to the candy, ice cream, and cocoa product, respectively, and R2 was ≥0.9998, showing a high level of linearity. The LOD and LOQ were 0.16 to 0.32 and 0.48 to 0.97 mg/L, respectively. As a result of repeated intra-day and interday experiments to validate the accuracy and precision of the analytical method, the recovery rates were 96.0-103.1% and 100.0-102.2%, respectively and the RSD% was 0.5-3.3% and 0.9-3.8%, respectively. Moreover, the measurement uncertainty was estimated to be 1.71-12.43% depending on the matrix and the measured concentration. In this study, betanine and isobetanine were quantified (8.4-3,823.4 mg/kg) by applying the developed analytical method to processed food products (n = 26; e.g., candy, ice cream, and other processed foods) labeled with beet red as a food additive.

Evaluation of the antioxidant potentials of extract and fractions of Vitex doniana fruit and identification of the bioactive metabolites using HPLC-DAD-MS analysis

Isoflavones and flavonoids in general found in fruits and vegetable act as natural antioxidants. This study was aimed at screening the isoflavone-rich fractions of Vitex doniana fruit extract for antioxidant activity using in vitro and in vivo models. The ethyl acetate and butanol fractions were screened for in vitro antioxidant activity by DPPH free radical scavenging and FRAP (Fe3+ Reducing Antioxidant Power) assays using ascorbic acid as standard. In vivo antioxidant activity was also tested against carbon tetrachloride-induced toxicity in mice using carbon tetrachloride (4 mL/kg) and silymarin (100 mg/kg) as standard. The ethyl acetate fraction and butanol Vacuum Liquid Chromatography (VLC) sub-fractions were subjected to High Performance Liquid Chromatography–Diode Array Detector (HPLC-DAD) and Liquid Chromatography-Mass Spectrometry (LC-MS) analyses. The ethyl acetate and butanol fractions inhibited DPPH radicals with an IC50 of 897 µg/mL and 2809.38 µg/mL respectively. Both fractions also showed mild FRAP result with EC50 of 1401 µg/mL and 7051 µg/mL respectively. The fractions produced significant decrease (P &lt; 0.05) in ALP levels only while ethyl acetate fraction caused a significant reduction in the value of only malondialdehyde. Both fractions also increased levels of superoxide dismutase (SOD). HPLC-DAD analysis led to the detection of cinnamic acid, protocatechuic acid and two isoflavones daidzein and genistein. Further LC-MS analysis confirmed the presence of the isoflavones tectorigenin, 5-O-methylgenistein, and 5-O-methyltectorigenin, among other flavonoids, peonidin, 5-methylpeonidin, methylmalvidin and kaempferol-3-O-(2''galloyl)-glucopyranoside. The detected isoflavones and other flavonoids may contribute to the observed mild in vitro and good in vivo antioxidant activity of V. doniana fruit extract and fractions.

Content determination of eight phenols in Ilex hainanensis harvested at different time by HPLC-DAD

This study intends to develop a high performance liquid chromatography-diode array detection(HPLC-DAD) method for simultaneous determination of chlorogenic acid, 2-hydroxymethyl-3-hydroxyl-1-butene-4-O-β-D-(6″-O-caffeoyl)-glucopyranoside, pubescenoside B, huazhongilexone-7-O-β-D-glucopyranoside, rutin, isochlorogenic acid B, isochlorogenic acid A, isochlorogenic acid C in Ilex hainanensis. The HPLC conditions are as follows: Waters XBridge C_(18 )column(4.6 mm×250 mm, 5 μm), mobile phase of 0.5% formic acid in water(A)-acetonitrile(B), gradient elution(0-8 min, 5%-12% B; 8-18 min, 12%-18% B; 18-30 min, 18%-25% B; 30-40 min, 25%-30% B; 40-42 min, 30%-80% B; 42-45 min, 80% B) at the flow rate of 0.8 mL·min~(-1), detection wavelengths of 282, 324, and 360 nm, column temperature of 25 ℃, and injection volume of 5 μL. The content of the 8 phenols in 8 samples was 0.30-6.29, 0.29-3.27, 0.15-10.4, 0.51-5.85, 0.49-9.02, 0.51-4.68, 1.93-13.4, and 0.87-5.95 mg·g~(-1), respectively. Moreover, the content of phenols in the samples collected in October was higher than that of samples harvested in other months. The established method is accurate and sensitive for the determination of phenols in I. hainanensis, which is useful for the quality improvement of this herbal medicine.

Determination of Chemical Compositions, Antioxidant and Enzyme Inhibitory Activities of Naturally Growing Chenopodium album subsp. iranicum Aellen

Chenopodium album has been used as folk medicine and nutrition for years by local people. This study aimed to investigate the phenolic compounds by Reversed Phase-High Performance Liquid Chromatography-Diode Array Detector (RP-HPLC-DAD), total phenolic content (TPC), and biological activities of the plant extracts prepared with three solvents (methanol, acetonitrile, and water) for the first time. Also, the chemical composition of essential oil and mineral content of the plant were determined by Gas Chromatography Mass-Spectrometry (GC-MS), and Inductively Coupled PlasmaOptical Emission Spectrometry (ICP-OES), respectively. The extracts of the plant were analyzed for the in vitro inhibitory activities against carbonic anhydrase (CA) and urease enzymes. The most abundant compound in methanol extract was catechin (157.666 mg L-1). Moreover, depending on the solvent used in the extracts, varied levels of phenolic acids such as gallic, protocatechuic, p-OH benzoic, ferulic, and syringic acids were identified. Thirty-four components were identified and methyl linolenate was found to be the main constituents of the essential oil (11.28 %). The methanol extract of the plant exhibited the best antioxidant value given as TPC 65.41±5.20 µg mL-1 GAE, FRAP 113.54±1.57 µM TEAC, DPPH• 191.1±3.55 µg mL-1 SC50, and ABTS•+ 74.7±1.55 µg mL-1 SC50, respectively. According to the mineral analyses, it was conducted that potassium and sodium were the most abundant minerals. The extracts were found as inactive against CA and showed a moderate urease inhibition effect (IC50:28.380±0.742 mg mL-1). The obtained results indicated that the plant extract could be used as an easily available natural antioxidants source for the food and pharmaceutical industry.

Secondary metabolic profiles and anticancer actions from fruit extracts of immature pomegranates.

Immature fruits from Punica granatum L. thinning are a neglected side product of pomegranate production with cumbersome disposal costs for farmers. To explore value potential of immature fruits from pomegranate ‘Wonderful’ cultivars, the compositional landscapes and antitumorigenic activities of pomegranate extracts from two different stages of maturation were assessed. Cancer cell proliferation and cytotoxicity was quantified in human lung H1299 and colon HCT116 adenocarcinomas by crystal violet staining, MTS assay and caspase-3 activity. High performance liquid chromatography—diode array detector (HPLC/DAD) and high performance liquid chromatography—electrospray ionization—mass spectrometry (HPLC/ESI-MS) analyses indicate that immature fruits are rich sources of gallotannins and ellagitannins, with the highest amounts contained in immature fruit peels. Biological investigations reveal a robust anticancer activity by those immature P. granatum fruit extracts, which reflected induction of tumor cytotoxicity and cell death mechanisms. Together, present observations suggest P. granatum byproducts from the thinning process may provide unexplored values for virtuous circular economy.

Air frying pretreatment and the recovery of lipophilic sinapates from the oil fraction of mustard samples.

Roasting of mustard seeds prior to oil extraction is a well-documented unit operation essential to produce canolol and other lipophilic sinapates. This study investigated the effectiveness of air frying as a seed roasting treatment operation for enhancing the recovery of lipophilic sinapates from various mustard samples and fractions/products. Air frying of seeds, powder, cake, bran, and flour from different mustard varieties was carried out at temperature-time combinations of 160, 170, and 180°C for 5, 10, 15, and 20min, respectively. Oil was extracted using the Soxtec method. Lipophilic sinapates were extracted from the oil using equal volumes of hexane to methanol 70% (v/v) and quantified by high performance liquid chromatography-diode array detection (HPLC-DAD). The total phenolic content (TPC) and antioxidant activity of the oils were also evaluated. The results showed a time-temperature dependency for the recovery of major oil-soluble sinapates in all mustard samples and fractions. The optimum air frying condition 180°C for 15min produced the maximum yield of canolol as well as other unidentified oil-soluble sinapates (retention time (RT)-7.7, RT-11.50, RT-14.95, and RT-16.24min). The oil from lower grade yellow mustard seeds (LGYMS) roasted at 180°C for 20 mins specifically had the highest TPC (3402.22± 58.79mg GAE/g oil), while LGYMS oils generally showed better antioxidant activities (2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric ion reducing antioxidant power (FRAP), and inhibition of linoleic acid oxidation) but were lower in metal ion chelating capacity. This information would be beneficial to the oil industry because air frying generated valuable canolol and other antioxidant lipophilic sinapates from mustard varieties and their fractions. PRACTICAL APPLICATION: A major limitation in the application of natural extracts in vegetable oils is the poor lipophilic nature of phenolic compounds. This study employed a new thermal treatment (air frying) in the recovery of canolol and other lipophilic antioxidants. Such treatments can enrich mustard-based ingredients with canolol and other lipophilic antioxidants for domestic and industrial applications.

Combination of cold induced HLLME with an effervescence-assisted DLLME based on deep eutectic solvent decomposition; application in extraction of some pyrethroid and carbamate pesticides from edible oils

ABSTRACT A cold-induced homogenous liquid–liquid microextraction method combined with solidification of floating organic droplets effervescent-assisted dispersive liquid–liquid microextraction has been developed for simultaneous extraction of several pyrethroid and carbamate pesticides from edible oils. The extracted analytes were determined by high performance liquid chromatography-diode array detector. For this purpose, 5 mL of edible oil sample was transferred into a glass test tube and it was mixed with 150 µL α-terpineol: acetic acid deep eutectic solvent. After vortexing (for 5 min), the mixture was placed into an ice: sodium chloride bath to adjust the solution temperature at −16℃. In this step, the oil sample was solidified, and the deep eutectic solvent was collected on top of the oil. Thus, it was collected and dispersed into 5.0 mL sodium carbonate solution at a concentration of 1.0 mol/L containing 2.5% w/v sodium chloride. In this step, the deep eutectic solvent was decomposed in the solution and α-terpineol dispersed in the sample solution. To obtain high extraction efficiency the effective parameters were optimised and under optimal conditions, the method showed broad linear ranges (2.6–500 ng/mL) with good coefficient of determinations ≥0.994. The extraction recoveries and enrichment factors of the method were in the ranges of 78–93% and 98–116%, respectively. The limits of detection and quantification were within the range of 0.2–0.8 and 0.6–2.6 ng/mL, respectively. The method was successfully used for the determination of the analytes in different edible oil samples.

Facile synthesis of uniform spherical covalent organic frameworks for determination of neonicotinoid insecticides

A uniform spherical structure covalent organic framework (TAPA-BPDA-COF) was prepared by a facile method at room temperature with tris(4-aminophenyl)amine (TAPA) and 4,4′-biphenyldicarboxaldehyde (BPDA) as building blocks. Based on the solid phase extraction with the TAPA-BPDA-COF as the sorbent and high performance liquid chromatography-diode array detection, a sensitive analytical method was established for the determination of four neonicotinoid insecticides from water and honey samples. Under the optimum conditions, good linear response for the quantification of the analytes was achieved in the range of 0.3–50.0 ng mL−1 for water samples and in the range of 8.0–500.0 ng g−1 for honey samples. The method recoveries fell in the range of 80.0–121.9% with RSDs less than 7.6%. The limits of detection at the signal to noise ratio of 3 were measured to be in the range of 0.08–0.12 ng mL−1 for water samples and 2.6–3.3 ng g−1 for honey samples, depending on compounds.

Designing a moderately hydrophobic sol-gel monolithic Carbowax 20 M sorbent for the capsule phase microextraction of triazine herbicides from water samples prior to HPLC analysis

The determination of triazine herbicides in water samples is of utmost importance, due to their persistence and excessive use. However, since the concentration of triazine pesticides in real samples is low, an extraction/preconcentration step is typically required. Capsule phase microextraction (CPME) is a recently introduced sample preparation technique in which highly efficient sol-gel sorbents are encapsulated in a tubular polymer membrane. This particular design integrates the filtration and stirring mechanism into one extraction device, enabling the application of CPME for in situ sampling. In this study, CPME coupled to high performance liquid chromatography-diode array detection (HPLC-DAD) was employed for the first time for the determination of six triazine herbicides (i.e., simazine, cyanazine, atrazine, prometryn, terbuthylazine and propazine) in water samples. Microextraction capsules containing a moderately hydrophobic sol‐gel Carbowax 20 M sorbent provided the highest extraction efficiency towards the examined pesticides. The main parameters affecting the adsorption and desorption steps of the CPME procedure were investigated and optimized. Under the selected conditions, limits of detection (signal/noise = 3.3) were 0.15 ng mL−1 for the target analytes. Moreover, the relative standard deviation for the within-day and between-days repeatability were less than 7.2% and 9.9%, respectively. The method was successfully applied to the analysis of mineral water, tap water, rainwater and lake water samples. The reported protocol could overcome the need for sample filtration prior to the sample preparation of the water samples, resulting in simplification of the overall sample handling, improved data quality with minimal loss of analytes and reduced sample preparation cost.

Development of a deep eutectic solvent-based ultrasound-assisted homogenous liquid-liquid microextraction method for simultaneous extraction of daclatasvir and sofosbuvir from urine samples

An ultrasound-assisted homogenous liquid–liquid microextraction method using a new deep eutectic solvent was proposed for the extraction of daclatasvir and sofosbuvir from urine. The analytes were determined by high performance liquid chromatography–diode array detector. The deep eutectic solvent was prepared by mixing p-aminophenol with tetrabutyl ammonium chloride. It was used in the extraction procedure as an extraction solvent. The amine group in structure of the prepared deep eutectic solvent led to its various solubility in different pHs. In this method, urine sample was placed in a glass test tube and then mixed with sodium chloride and its temperature adjusted at 50 °C. Then, the deep eutectic solvent was dissolved in the solution by manually shaking. In the following, an ammonia solution was added to the solution and the mixture was sonicated for 4 min. After centrifugation, an aliquat of the sedimented phase was injected into the determination system. Low limits of detection (daclatasvir 1.0 and sofosbuvir 1.3 μg/L) and quantification (daclatasvir 3.3 and sofosbuvir 4.0 μg/L), high enrichment factor (daclatasvir 96 and sofosbuvir 90) and extraction recovery (daclatasvir 96 and sofosbuvir 90 %), and good percision (relative standard deviation ≤9.3 %) were obtained. The introduced method was successfully applied in the determination of daclatasvir and sofosbuvir concentrations in urine samples.

Simultaneous quantifications of four purine derivatives biomarkers in cow milk by SPE HPLC-DAD

In this study, simultaneous quantification of allantoin, uric acid, xanthine, and hypoxanthine in cow milk by solid phase extraction (SPE) and high performance liquid chromatography-diode array detection (HPLC-DAD) method was perform. Five different SPE cartridges were tested in order to evaluate the isolation of purine derivatives (PD) from cow milk. Chromatography was carried out on ODS-2 Hypersil column and 0.05 M (NH&lt;sub&gt;4&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt; buffer solution (pH = 7.76) as mobile phase. The HPLC-DAD validated method showed a linearity with regression coefficients higher than 0.999 and the limits of detection and quantification with values in the range 0.09–0.74 µg mL&lt;sup&gt;–1&lt;/sup&gt; and 0.27–2.24 µg mL&lt;sup&gt;–1&lt;/sup&gt;, respectively. The method showed good precision with a relative standard deviation (RSD) below 4.48%, while the accuracy ranged from 95.34 to 104.47% for all analytes. The best recovery degree of PD by SPE were obtained on Strata SCX cartridge for xanthine (87.79%) and hypoxanthine (89.02%); on Strata NH&lt;sub&gt;2&lt;/sub&gt; for allantoin (35.09%) and on Strata C8 for uric acid (101.08%). Finally, the HPLC-DAD method with SPE on SCX cartridges was applied to quantify the PD in a batch of thirty cow milk samples.

Graphene oxide-functionalized mesoporous silica for online in-tube solid-phase microextraction of polycyclic aromatic hydrocarbons from honey and detection by high performance liquid chromatography-diode array detector

In order to develop an online detection method for polycyclic aromatic hydrocarbons (PAHs) in honey, graphene oxide-functionalized mesoporous silica was prepared and introduced as the coating in the field of in-tube solid-phase microextraction. An extraction tube was coupled to high performance liquid chromatography with diode array detector, and the online analytical system was constructed. After the main extraction and desorption conditions were optimized, a sensitive and online method based on matrix-matched calibration was established towards trace PAHs in honey. The method exhibited wide linear range from 0.8 ng g−1 to 250 ng g−1 and low detection limit of 0.25 ng g−1, and the enrichment effect reached 2719. The proposed method was validated and successfully applied to the analysis of six honey samples. The extraction tube showed good durability and acceptable chemical stability during the experiment.