Combination of temperature-assisted ternary phase homogenous liquid-liquid extraction with deep eutectic solvent-based dispersive liquid-liquid microextraction for the extraction of phytosterols from cow milk and cream samples.

A three-phase homogenous liquid-liquid extraction method followed by deep eutectic solvent-based dispersive liquid-liquid microextraction has been used for the extraction and preconcentration of some phytosterols from cow milk and cream samples. In this method, cow milk or melted cream was transferred into a glass test tube and a mixture of sodium hydroxide solution (as fatty acids saponification agent) and acetonitrile (as extraction/dispersive solvent) was added to the solution. The mixture was shaken manually and placed in a water bath. After dissolving sodium chloride and centrifugation, the obtained supernatant phase (acetonitrile) was removed and mixed with ethyl methyl ammonium chloride: phenyl acetic acid deep eutectic solvent at microliter level. Under optimum conditions, low limits of detection (1.6-4.1 µg/L) and quantification (5.3-13.1 µg/L), high enrichment factors (138-207), and extraction recoveries (55-83%), and good precision (relative standard deviations ≤ 6.8%) can be obtained. The method was done on different milk and cream samples and the results showed that total phytosterols level in all samples were in the permitted level established by the National Standard Organization Guidelines, except for three cream samples.

The effects of lemon balm (Melissa officinalis L.) on depression and anxiety in clinical trials: A systematic review and meta-analysis.

A systematic review and a meta-analytic approach were considered to investigate the effects of lemon balm as a medicinal herb on anxiety and depression in clinical trials and its side effects. All randomized clinical trials published up to October 30, 2020 that examined lemon balm in patients with symptoms of depression or anxiety, with acute or chronic manifestations, were searched in 12 online databases. Statistical analysis was performed using RevMan software. Continuous data were analyzed using standardized mean differences. Statistical heterogeneity was assessed using Chi2 , I2 , and p value tests. Based on meta-analysis results, lemon balm significantly improved mean anxiety and depression scores compared with the placebo (SMD: -0.98; 95% CI: -1.63 to -0.33; p = 0.003), (SMD: -0.47; 95% CI: -0.73 to -0.21; p = 0.0005) respectively, without serious side effects. Current evidence suggests that lemon balm may be effective in improving anxiety and depressive symptoms, particularly in the acute setting. Due to the high level of heterogeneity between studies, results should be interpreted with caution. The small number of clinical trials and differences between their methods were the limitations of the present study. Further high-quality studies are needed to firmly establish the clinical efficacy of the lemon balm.

Melissa officinalis L. hydro-alcoholic extract inhibits anxiety and depression through prevention of central oxidative stress and apoptosis.

NEW FINDINGS: What is the central question of this study? How does an extract of Melissa officinalis L. ameliorate anxiety- and depressive-like behaviour of mice? What is the main finding and its importance? An extract of Melissa officinalis L. possessed anxiolytic and anti-depressant effects, which could mainly be mediated through its antioxidant and anti-apoptotic properties. ABSTRACT: This study evaluated the effects of a hydro-alcoholic extract of Melissa officinalis (HAEMO) on anxiety- and depressive-like behaviours, oxidative stress and apoptosis markers in restraint stress-exposed mice. In order to induce a depression-like model, mice were subjected to restraint stress (3 h day-1 for 14 days) and received normal saline or HAEMO (50, 75 and 150 mg kg-1  day-1 ) for 14 days. The administered doses of HAEMO were designated based on the concentration of one of the main phenolic compounds present in the extract, rosmarinic acid (2.55 mg kg-1 at lowest dose); other phytochemical analyses including assays for antioxidant activity, total phenols and flavonoids were also carried out. The behavioural changes in an open field task, elevated plus maze, tail suspension and forced swimming tests were evaluated. Also, malondialdehyde (MDA) levels and enzyme activities of superoxide dismutase and glutathione peroxidase, and total antioxidant capacity were assessed in the prefrontal cortex and hippocampus. Moreover, levels of Bcl-2, Bax and caspase 3 in the brain as well as serum concentration of corticosterone were evaluated. HAEMO (75 and 150 mg kg-1 ) significantly reversed anxiety- and depressive-like behaviours. Also, HAEMO reduced MDA levels, enhanced enzymatic antioxidant activities and restored serum levels of corticosterone. An immunoblotting analysis also demonstrated that HAEMO decreased levels of pro-apoptotic markers and increased anti-apoptotic protein levels in the prefrontal cortex and hippocampus of restraint stress-exposed mice. Our findings suggested that HAEMO reduced inflammation and had anxiolytic and antidepressant effects in mice.

Medicinal Plants as Potential Hemostatic Agents.

PURPOSE: Medicinal plants with a variety of phytochemical ingredients remain a potential source for new drug discovery. The use of medicinal herbs in a wide range of diseases and symptoms, such as bleeding, is prevalent in traditional and ethno medicine worldwide. Thus, this work provides a comprehensive review of medicinal plants or their isolated compounds, with respect to their ethno-medicinal use, which have demonstrated the stimulating effect on the hemostasis process. METHODS: The relevant studies were withdrawn from electronic databases including Pubmed, EMBASE and Web of Science with a structured search methodology. RESULTS: The total of 17 medicinal plants with hemostatic activity were extracted. The most frequently studied plant families were Compositae, Lamiaceae, Fabaceae, and Asteraceae. Bioactive compounds exerting hemostatic activity included tannins, iridoid glycosides, glycoconjugate, lignan, saponins and phenolic compounds. The most attributed mechanisms include coagulation stimulation via increasing the factor XII activity and plasma fibrinogen levels, the fibrinolysis inhibition, vascular or smooth muscle constriction and platelet aggregation. The most important adverse effects of high dose extract or isolated compounds administration were hepatotoxicity and nephrotoxicity. CONCLUSION: This review provides a list of medicinal plants with hemostatic activity that could be used as valuable sources of new plant-based hemostatic agents. Furthermore, this could be practical in detecting possible interactions of plants with anticoagulant, antiplatelet, fibrinolytic and antifibrinolytic medications.

A three-phase solvent extraction system combined with deep eutectic solvent-based dispersive liquid-liquid microextraction for extraction of some organochlorine pesticides in cocoa samples prior to gas chromatography with electron capture detection.

A sample pretreatment method based on the combination of a three-phase solvent extraction system and deep eutectic solvent-based dispersive liquid-liquid microextraction has been introduced for the extraction of four organochlorine pesticides in cocoa samples before their determination by gas chromatography-electron capture detection. A mixture of sodium chloride, acetonitrile, and potassium hydroxide solution is added to cocoa bean or powder. After vortexing and centrifugation of the mixture, the collected upper phase (acetonitrile) is removed and mixed with a few microliters of N,N-diethanol ammonium chloride: pivalic acid deep eutectic solvent. Then it is rapidly injected into deionized water and a cloudy solution is obtained. Under optimum conditions, the limits of detection and quantification were found to be 0.011-0.031 and 0.036-0.104 ng/g, respectively. The obtained extraction recoveries varied between 74 and 92%. Also, intra- (n = 6) and interday (n = 4) precisions were less than or equal to 7.1% for the studied pesticides at a concentration of 0.3 ng/g of each analyte. The suggested method was applied to determine the studied organochlorine pesticide residues in various cocoa powders and beans gathered from groceries in Tabriz city (Iran) and aldrin and dichlobenil were found in some of them.

Synthesis and characterization of phosphocholine chloride-based three-component deep eutectic solvent: application in dispersive liquid-liquid microextraction for determination of organothiophosphate pesticides.

BACKGROUND: A new type of deep eutectic solvent based on three components using phosphate salts has been synthesized, characterized, and applied in the extraction of eight organothiophosphate pesticides from honey samples. In this study, the deep eutectic solvent was prepared from phosphocholine choline chloride as a hydrogen bond acceptor and dichloroacetic acid and decanoic acid as hydrogen bond donors. The method consisted of two steps in which initially the analytes were extracted from the samples into a water-miscible organic solvent. In the second step, the extracted phase was mixed with the prepared deep eutectic solvent and the mixture was used in the following dispersive liquid-liquid microextraction method. RESULTS: The method was validated under optimal conditions, and it was found that it has low limits of detection (0.05-0.10 ng g-1 ) and quantification (0.19-0.36 ng g-1 ), good linearity (r2 ≥ 0.994), broad linearity (0.36-1000 ng g-1 ), and satisfactory repeatability (relative standard deviation ≤10% for intra- (n = 6) and inter-day (n = 4) precisions at a concentration of 2 ng g-1 of each analyte). CONCLUSION: The proposed method was applied in different honey samples, and malathion was found at a concentration of 29 ng g-1 in one sample. © 2019 Society of Chemical Industry.

Deep eutectic solvent based homogeneous liquid-liquid extraction coupled with in-syringe dispersive liquid-liquid microextraction performed in narrow tube; application in extraction and preconcentration of some herbicides from tea.

A homogeneous liquid-liquid extraction performed in narrow tube coupled to in-syringe-dispersive liquid-liquid microextraction based on deep eutectic solvent has been developed for the extraction of six herbicides from tea samples. In this method, sodium chloride as a separation agent is filled into the narrow tube and the tea sample is placed on top of the salt. Then a mixture of deionized water and deep eutectic solvent (water miscible) is passed through the tube. In this procedure, the deep eutectic solvent is realized as tiny droplets in contact with salt. By passing the droplets from the tea layer placed on the salt layer, the analytes are extracted into them. After collecting the solvent as separated layer, it is mixed with another deep eutectic solvent (choline chloride/butyric acid) and the mixture is dispersed into deionized water placed in a syringe. After adding acetonitrile to break up the cloudy state, the collected organic phase is injected into gas chromatography-mass spectrometry. Under optimal conditions, limits of detection and quantification in the ranges of 2.6-8.4 and 9.7-29 ng/kg, respectively, were obtained. The extraction recoveries and enrichment factors in the ranges of 70-89% and 350-445 were obtained, respectively.

Identification and applications of neuroactive silk proteins: a narrative review.

In traditional medicine, natural silk is regarded as a cognitive enhancer and a cure for ameliorating the symptoms of heart disease, atherosclerosis, and metabolic disorders. In this review, general characteristics of both silk proteins, fibroin and sericin, extracted from silkworm Bombyx mori and their potential use in the neuronal disorders was discussed. Evidence shows that silk proteins exhibit neuroprotective effects in models of neurotoxicity. The antioxidant, neuroprotective, and acetylcholinesterase inhibitory mechanisms of silk proteins could prove promising in the treatment of neurodegenerative diseases. Owing to their excellent neurocompatibility and physicochemical properties, silk proteins have been used as scaffolds and drug delivery materials in the neuronal tissue engineering. These data support the potential of silk proteins as an effective complementary agent for central and peripheral neurological disorders.

The Effect of Extraction by Pressing at Different Temperatures on Sesame Oil Quality Characteristics.

Sesame oil has been widely used in the daily diet due to its high nutritional value. Sesame oil is extracted at industrial scales and also in small scale by cold pressing at different temperatures. In this research, sesame oil was extracted by pressing at four temperatures, namely, 30 (control sample), 60, 90 and 120 °C, to evaluate its effects on the quality of extracted oils. Oil extraction yields were increased from 38 to 51% by increasing the pressing temperature. The highest amount of peroxide and acid values were related to the oil extracted at 120 °C. Tocopherols and total phenol content were reduced by the increasing the pressing temperature, and the highest amounts of these bioactive components were related to the control sample. The results of the fatty acids profile showed that the composition of oils extracted at different temperatures did not differ significantly (p > 0.05). The results of the present study give a clear picture about the effects of different pressing temperatures on the sesame oil quality and extraction yield, and can be useful in the extraction unit optimization.

Changes in the quality of oil extracted by hot pressing from black cumin (Nigella sativa) seeds and by solvent from the obtained cake during refining.

In this study, oil was extracted from black cumin (Nigella sativa) seed (BCS) by press, and oil was extracted from the obtained cake with a solvent. The changes in the quality of both crude oils obtained by pressing and by solvent were investigated during refining. Findings revealed that the p-anisidin value (p-AV) and fatty acid profile did not change significantly, but there were significant differences (p < .05) in the peroxide value (PV), reflective index, pigment contents, free fatty acid content (FFA%), and antioxidant activity (total phenol content (TPC), thymoquinone, and DPPH inhibition) of BCS oils obtained by the two different methods. PV and FFA decreased to less than 15 meqO2/kg and 0.3%, respectively, in the refined oil. The TPC (65%), thymoquinone (45-97%), carotenoids (86-89%), and chlorophyll (75-85%) were removed from BCS oil, but the DPPH value was raised by about 33%. The current study gives a clear picture of the changes during refining in BCS oil, which can be a useful guide in food applications.

Quality improvement of oil extracted from flaxseeds (Linum usitatissimum L.) incorporated with olive leaves by cold press.

Flaxseed oil has a high amount of α-linolenic acid (an ω3 essential fatty acid), but it is very prone to oxidation. Therefore, olive leaves were used as a rich source of phenolic compounds with flaxseeds upon oil extraction by cold press to enhance the oxidative stability of extracted oils. Oil from flaxseeds with unblanched leaves and blanched leaves at level of (0 [control sample], 2.5, 5, 7.5, and 10% w/w) was extracted by cold press. Quality of extracted oils was evaluated for 90 days of storage at room condition. Incorporation of unblanched olive leaves could increase the acid value of the extracted oils up to 2.0 (mg KOH/g oil) compared to the other samples. Oxidation of the flaxseed oil could be delayed by the addition of blanched olive leaves up to 5%. Oil extracted from flaxseeds incorporated with blanched olive leaves had higher content of carotenoids (up to 33.7 mg/kg oil), chlorophylls (up to 35.7 mg/kg oil), and phenolic compounds (up to 200 mg/kg oil). Also, oxidative stability of extracted oils was higher up to 7.5% of blanched olive leaves (11.4 h) compared to control sample (7.2 h) and other oil samples. Polyunsaturated fatty acids of the oil samples were well preserved by the incorporation of blanched olive leaves. Based on the obtained results, incorporation of suitable amount of blanched olive leaves (up to 7.5%) with flaxseeds before oil extraction by press can be an appropriate procedure to produce oils with high content of bioactive components and suitable oxidative stability.

Designing and fabrication of colloidal nano-phytosomes with gamma-oryzanol and phosphatidylcholine for encapsulation and delivery of polyphenol-rich extract from pomegranate peel.

Nano-carriers are well-known delivery systems to encapsulate different bioactive compounds and extracts. Such nano-systems are used in various food and drug areas to protect active ingredients, increase bioavailability, control the release, and deliver bioactive substances. This study aimed to design and fabricate a stable colloidal nano-delivery system to better preserve the antioxidant properties of pomegranate peel extract (PPE) and protect its sustained release in a gastrointestinal model. To achieve this goal, a nano-phytosomal system was fabricated with plant-based, cost-effective, and food-grade compounds, i.e., phosphatidylcholine (PC) and gamma-oryzanol (GO) for encapsulation of PPE. To fabricate the nano-phytosomes, thin film hydration/sonication method was used. The parameters of particle size, zeta potential, polydispersity index (PDI), loading capacity (LC), and encapsulation efficiency (EE) were investigated to evaluate the efficiency of the produced nano-system. In summary, the size, zeta potential, PDI, LC, and EE of homogenous spherical PC-GO-PPE nano-phytosomes (NPs) in the ratio of 8:2:2 % w/w were achieved as 60.61 ± 0.81 nm, -32.24 ± 0.84 mV, 0.19 ± 0.01, 19.13 ± 0.30 %, and 95.66 ± 1.52 %, respectively. Also, the structure of NPs was approved by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). The optimized NPs were stable during one month of storage at 4 °C, and changes in the size of particles and PPE retention rate were insignificant (p > 0.05). The nano-encapsulation of PPE significantly decreased the loss of its antioxidant activity during one month of storage at 4 °C. The optimized NPs exhibited prolonged and sustained release of PPE in a gastrointestinal model, so that after 2 h in simulated gastric fluid (SGF) and 4 h in simulated intestinal fluid (SIF), 22.66 ± 2.51 % and 69.33 ± 4.50 % of initially loaded PPE was released, respectively. Optimized NPs had considerable cytotoxicity against the Michigan Cancer Foundation-7 cell line (MCF7) (IC50 = 103 µg/ml), but not against Human Foreskin Fibroblast cell line (HFF-2) (IC50 = 453 µg/ml). In conclusion, spherical PC-GO-PPE NPs were identified as a promising delivery system to efficiently encapsulate PPE, as well as protect and preserve its bioactivity, including antioxidant and cytotoxicity against cancer cell line.

Evaluation of the qualitative properties of the oil extracted from the mixture of Helianthus annuus and Nigella sativa seeds during heating.

The oil obtained from black cumin (Nigella sativa) seeds has many health-effective properties, which is used in food applications and in traditional medicine. One practical method to extract its oil is mixing with other seeds such as sunflower (Helianthus anuus) seeds before oil extraction by press. The effectiveness of the cold-press oil obtained from the mixture of black cumin seeds (BS) and sunflower seeds (SF) in different proportions 100:0, 95:5, 90:10, 85:15 and 0:100 (w/w) was studied to evaluate their qualitative properties including peroxide value (PV), acid value, p-anisidine value (AnV), pigments (carotenoid and chlorophyll) content, polyphenols, and profile of fatty acids during heating process (30-150 min at 180 °C). The results revealed that the acid and p-anisidine value of the all samples enhanced with the extension of the heating time, and the peroxide value increased at the beginning of the heating and then decreased with the prolongation of the heating time (p < .05). With the increase of temperature and heating time, the peroxide of sunflower oil increased with a higher slope and speed than that of black seed and blends oil. Changes in the PV and AnV were the fastest in sunflower oil. Blending and heating caused considerable changes in the fatty acid composition of oils, especially myristic, palmitic, and stearic acids. Moreover, the levels of certain unsaturated fatty acids, namely linoleic, oleic, and linolenic acids declined after heating. The carotenoids, chlorophyll and total phenol content decreased gradually during heating treatments. Among extracted oils, SF:BS (15%) had the good potential for stability, with total phenol content of 95.92 (Caffeic acid equivalents/100 g), PV of 2.16 (meq O2/kg), AV of 2.59 (mg KOH/g oil), and AnV of 8.08 after the heating. In conclusion, oil extracted from the mixture of SF and BS can be used as salad and cooking oils with a high content of bioactive components and positive nutritional properties.

Effects of Mild Thermal Processing and Storage Conditions on the Quality Attributes and Shelf Life of Truffles (Terfezia claveryi).

This study investigated the effects of two mild thermal processing (MTP) (63 °C, 40 °C, 3 min) methods, in a brine storage medium (7-16% (w/v) NaCl) and a vinegar solution (5% vinegar, 1% salt, and 0.5% sugar), on some physicochemical properties of truffles (Terfezia claveryi). Weight loss, phenolic compounds, firmness, ascorbic acid and microbial loads were evaluated during 160 days of storage. It was demonstrated that a 5% vinegar treatment with 63 °C MTP was effective to reduce the weight loss, microbial spoilage and increased firmness and of truffles during storage. However, phenolic compounds and ascorbic acid content were decreased by heating. Both MTPs inhibited the microbial load, but the 63 °C, 3 min MTP was most effective and resulted in an immediate (3.05-3.2 log CFU/g) reduction in the total aerobic bacteria (TAB) and remained at an acceptable level during storage, while the 40 °C, 3 min MTP reduced (1.12-2 log CFU/g) of the TAB. The results of this study suggest that the 63 °C MTP and immersion in 5% vinegar increased the shelf life of the truffles without perceptible losses in quality attributes.

An overview of effects of gamma radiation on the biological, physicochemical and nutritional parameters of oilseeds and oils.

PURPOSE: Gamma irradiation is a non-thermal method for prolonging the shelf-life of foods and it is a possible alternative technology for oilseeds. After harvest, the development of pests and microorganisms, as well as the reactions caused by enzymes reason numerous problems in the oilseeds. Gamma radiation is one of the methods that could inhibit undesired microorganisms, but it can also change the physicochemical and nutritive characteristics of oils. CONCLUSION: This paper is a brief review of recent publications on the effects of gamma radiation on the biological, physicochemical and nutritional parameters of oils. Overall, gamma radiation is a safe and environmentally friendly method that improves the quality, stability and safety characteristics of oilseeds and oils. In the future, there may also be many health reasons to produce oils using gamma radiation. Investigation of other radiation techniques such as x-rays and electron beams have a good potential once the specific doses that would free them from pests and contaminants have been identified while conserving the benefits without altering their sensory properties.

Spectroscopic aspects on the interaction of nisin with serum albumin: thermodynamic and kinetic studies.

Introduction: Nisin is a bacteriocin produced by Streptococcus and Lactococcus species and has antimicrobial activity against other bacteria. Nisin omits the need to use chemical preservatives in food due to its biological preserving properties. Methods: In the present in vitro study, we investigated nisin interaction with bovine serum albumin (BSA) using fluorescence spectroscopy and surface plasmon resonance (SPR) analysis to obtain information about the mechanisms of BSA complex formation with nisin. Results: The BSA fluorescence intensity values gradually diminished with rising nisin concentration. The BSA fluorescence quenching analysis indicated that a combined quenching mechanism plays the main role. Finally, the Kb values were reduced with increasing temperature, which is demonstrative of nisin-BSA complex stability decrease at high temperatures. The negative values of ΔH° and ΔS° showed that hydrogen bonds and van der Waals forces are the foremost binding force between BSA and nisin. Meanwhile, the negative values of ΔG° demonstrated the exothermic and random nature of the reaction process. The results of the SPR verified the gained results through the fluorescence spectroscopy investigation, which denoted that the BSA affinity to nisin diminished upon increasing temperature. Conclusion: Overall, fluorescence spectroscopy and SPR results showed that the BSA interaction with nisin decreased with rising temperatures.

Ultrasonication/dynamic maceration-assisted extraction method as a novel combined approach for recovery of phenolic compounds from pomegranate peel.

According to recent studies, pomegranate peel (PP) has the potential to be inverted from environmental pollutant waste to wealth due to possessing valuable phenolic compounds at a higher amount compared to edible parts. So far, different types of biological activities such as antimutagenic, antiproliferative, anti-inflammatory, and chemo-preventive properties were stated for pomegranate peel extract (PPE) according to chemical composition. In the present research, the probable intensifying effects of two extraction methods and optimum conditions for novel combined method of ultrasonication and dynamic maceration-assisted extraction of PPE using response surface methodology (RSM) were determined. A Box-Behnken Design (BBD) was employed to optimize three extraction variables, including sonication time (X1), sonication temperature (X2), and stirring speed (X3) for the achievement of high extraction yield of the phenolic compounds and antioxidant activity. The optimized conditions to obtain maximum extraction efficiency were determined as X1 = 70 min, X2 = 61.8°C, and X3 = 1000 rpm. The experimental values were in line with the values anticipated by RSM models, which indicates the appropriateness of the applied quadratic model and the accomplishment of RSM in optimizing the extraction conditions. The results suggest that the extraction of PPE by mix of ultrasonication as a modern method and dynamic maceration as a conventional method could improve its bioactive extractability and the obtained values were higher than any of the methods used. In other words, these two methods together have intensifying effects in increasing extraction efficiency which could further be utilized in food and agricultural industry.

Effect of Refined Edible Oils on Neurodegenerative Disorders.

Neurodegenerative diseases are comprise a prominent class of neurological diseases. Generally, neurodegenerative diseases cannot be cured, and the available treatments can only regulate the symptoms or delay the disease progression. Among the several factors which could clarify the possible pathogenesis of neurodegenerative diseases, next to aging as the main risk, the dietary related diseases are the most important. Vegetable oils, which are composed of triacyclglycerols as the main components and several other components in a trace amount, are the main part of our diet. This review aims to study the effect of refined or unrefined vegetable oil consumption as a preventive or aiding strategy to slow or halt the progression of neurodegenerative diseases. In the refining process, owing to the chemical materials or severe temperatures of the refining process, removal of the desirable minor components is sometimes unavoidable and thus a worrisome issue affecting physical and neurological health.

Development of an Ion-Pair Dispersive Liquid-Liquid Microextraction Method Based on a Ternary Deep Eutectic Solvent for Determination of Some Herbicide Residues in Edible Oil Samples.

An ion-pair deep eutectic solvent (DES)-based dispersive liquid-liquid microextraction method was introduced and applied for the extraction of some acidic herbicides from edible oil samples prior to their determination by high performance liquid chromatography. First, a ternary DES composed of decanoic acid, dichloroacetic acid, and phosphocholine chloride is prepared under mild conditions. Then, the analytes are extracted into an alkaline solution from the oil samples by deprotonation of the herbicides. Afterward, the deprotonated analytes are extracted into the prepared DES with the aid of tri-butyl amine (as an ion-pair agent) in the presence of acetic acid (as a pH adjustment agent and dispersive solvent). The validation parameters indicated that the method has low limits of detection (0.09-0.72 ng mL-1) and quantification (0.30-2.3 ng mL-1), an acceptable percision (relative standard deviation ≤  9.0%) and high extraction recoveries (85-94%), and enrichment factors (566-626). The method was used in the analysis of 35 edible oil samples to assessment the studied analytes and the presence of haloxyfop was confirmed in three corn oils.

Aptasensing of ciprofloxacin residue using graphene oxide modified with gold nanoparticles and branched polyethyleneimine.

Precise monitoring of antibiotic residues in aqueous solution is of vital significance for safeguarding the environment and food resources. Herein, a convenient platform was fabricated for the electrochemical assay of ciprofloxacin (CFX) in real milk samples using aminated aptamer and graphene oxide nanogold-functionalized branched polyethyleneimine (GO-PEI-AuNPs) nanocomposite. For the first time, a gold electrode was modified with GO-PEI-AuNPs. The modified surface endowed excellent electrochemical substrates with large surface areas, excellent electron transfer rates, and suitable capabilities to firmly attach high amounts of aptamer. After further modification of substrate with CFX specific aptamer a recognition probe enabling selective and sensitive determination of CFX was realized. All of the aptasensor fabrication steps were surveyed via cyclic voltammetry techniques. The construction and morphology of the GO-PEI-AuNPs composite were evaluated by UV-Vis spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy. Under optimal conditions, the suggested scaffold can offer an acceptable linear range of 0.001 to 100 µM and a low limit of quantification of 0.001 µM for selective and sensitive monitoring of CFX in real samples. The effectiveness of the apta-assay was confirmed by detection of CFX in pasteurized and local milk samples for which suitable analytical results were achieved. It is expected that the developed substrate can be facilely extended to other aptamer-based multiplex screening platforms in actual food and environmental samples.