High-performance Liquid Chromatography-diode Array Detection Research Articles

Oxidative Stability of Novel Peptides (Linusorbs) in Flaxseed Meal-Fortified Gluten-Free Bread

Flaxseed meal, rich in water-soluble gums, improves the texture of gluten-free (GF) products. Bioactive antioxidant peptides from flaxseed, known as linusorbs (LOs) or cyclolinopeptides, may provide health benefits. However, the stability of flaxseed-derived LOs during dough preparation, baking, and storage remains unclear. To investigate this, GF bread dough and bread were prepared with flaxseed meal, and the LO content was determined in the flaxseed meal, the bread flour with the flaxseed meal, the dough, and the bread. The LO levels were also monitored during storage at various temperatures (−18 °C, 4 °C, and 22–23 °C) for 0, 1, 2, and 4 weeks using high-performance liquid chromatography–diode array detection (HPLC-DAD). The levels of oxidized LOs, such as [1–9-NαC],[1-(Rs,Ss)-MetO]-linusorb B2 (LO14), remained relatively stable in the flaxseed meal and the flour derived from it across under all conditions for up to 4 weeks. Due to microbial contamination, the dough could not be stored at either 4 or 21 °C, and the bread could only be stored at 21 °C for one week. However, the bread and dough could be stored for up to 4 weeks at −18 °C, and the bread at 4 °C, without a significant loss of LOs. The main changes in LOs occurred during processing rather than storage. Reduced LOs were found in higher concentrations in the flour and meal compared to the dough and bread, without a corresponding increase in oxidized LOs. The flaxseed meal-fortified bread maintained oxidative stability when stored at low temperatures. This is the first study to investigate the effect of baking conditions on LO content and antioxidant properties.

Construction of novel hyper-crosslinked polymers with adjustable hydrophilicity for efficient extraction of nitroimidazoles.

To effectively control food safety risks caused by nitroimidazoles (NDZs), a sensitive detection method was established on the basis of a newly-developed solid-phase extraction (SPE) sorbent named as Phl-TBM that is a porous polymer prepared by crosslinking natural phloretin with (2,4,6-tris(bromomethyl)mesitylene. The Phl-TBM presented outstanding NDZs adsorption capacity, which can be ascribed to its well-developed porosity and multiple hydrogen bonding sites. With Phl-TBM as SPE sorbent, NDZs were successfully isolated and enriched from lake water, Basa fish, and beef before being assayed by high-performance liquid chromatography-diode array detector. This Phl-TBM based method has a detection limit of 0.02-0.06 ng mL-1 in lake water, 0.60-1.50 ng g-1 in Basa fish, and 0.70-1.20 ng g-1 in beef. The method recoveries are 80.0-120 % with relative standard deviations less than 8.1 %. This study presents an effective and feasible approach for detection of NDZs residues at trace level.

UiO-66 with missing cluster defects for high-efficient extraction and enrichment of benzoylurea insecticides.

The creation of defects in crystalline structures can tune metal-organic frameworks (MOFs) properties, such as improving their adsorptive and catalytic performance with producing more porosity and active sites. In this work, the bimetallic UiO-66 containing Zn and Zr was prepared. And then UiO-66 with missing cluster defects (UiO-66-1/3) were obtained by acid washing to remove the Zn nodes. UiO-66-1/3 was used as sorbent of dispersive solid-phase extraction (dSPE) to extract and enrich (BUs). Combination with high-performance liquid chromatography-diode array detector (HPLC-DAD) was developed to detect trace BUs in soil samples. Adsorption equilibrium can be reached in 3 min. The method possesses high enrichment factor (202-325), low detection limit (0.005-0.04 ng·mL-1), and wide linear range (0.02-200 ng·mL-1). In addition, the recovery rate of UiO-66-1/3 as an adsorbent was still higher than 95% after reused for 16 times. This work provides a new material for the enrichment and detection of benzoylurea insecticides in the environment.

Fe3O4@SiO2/GO/HKUST-1 nanocomposite for quercetin extraction and preconcentration followed by its determination using HPLC.

Quercetin, a key flavonoid found in many fruits and vegetables, offers notable health benefits, including antioxidant, antiviral, and antitumor properties. Yet, isolating it from complex plant materials is challenging. This research aimed to develop a selective and efficient sorbent to clean up real sample matrices and pre-concentrate quercetin, enhancing its detection using high-performance liquid chromatography (HPLC). Several metal organic frameworks (MOFs) were synthesized and initially, their abilities to sorption of quercetin from aqueous and alcohol media were examined. Among them, HKUST-1 showed the best performance. To improve the efficiency of this MOF, its composite with graphene oxide (GO) was prepared (Fe3O4@SiO2/GO/HKUST-1) and was employed for quercetin extraction through magnetic dispersive micro solid-phase extraction. The effect of different parameters was examined and the kinetic, thermodynamic, and isotherm of the sorption process was studied. The related results showed the system followed the pseudo-second-order kinetic model, with the Temkin and Langmuir isotherm models applicable in aqueous and methanol solutions, respectively. The method enabled rapid preconcentration and clean up within 20 min, with a 99.6% adsorption efficiency using just 5mg of sorbent. The nanocomposite demonstrated an adsorption capacity of 29.3mg/g and effectively extracted quercetin from red onion samples, achieving recovery rates between 75% and 98% for HPLC-diode array detector analysis. PRACTICAL APPLICATION: Quercetin is a common polyphenolic compound, which is widely found in plant materials such as onions. Owing to its medicinal effects including anti-inflammatory, anti-oxidant, anti-cancer, cardioprotective, anti-bacterial, anti-viral, and anti-allergic features, it has widespread usage in pharmacology and preparation of food preservers. In this study, Fe3O4@SiO2/GO/HKUST-1 nanocomposite was synthesized for extraction and preconcentration of quercetin from an onion sample. Very low amounts of this sorbent indicated high adsorption percentage and adsorption capacity for quercetin. This method was simple, fast, cost-effective, precise, and accurate, which exhibited a potential for extraction of quercetin in a large scale.

Development and Application of a Robust Imine-Based Covalent Organic Framework for Stir Bar Sorptive Extraction of Estrogens in Environmental Water.

A covalent organic framework (COF) based on imine was synthesized using 2,5-dihexoxyterephthalaldehyde (DHT) and 1,3,5-tris(4-aminophenyl) benzene (TAPB) as starting materials. The TAPB-DHT-COF exhibited satisfactory chemical stability, making it a promising adsorbing material for stir bar sorptive extraction (SBSE) of four estrogens, including estrone (E1), β-estradiol (E2), hexestrol (HES), and mestranol (MeEE2), in ambient water samples. The extracted analytes were subsequently analyzed using a high-performance liquid chromatography-diode array detector (HPLC-DAD). A series of parameters affecting the SBSE process, such as solution pH, ionic strength, extraction time, and desorption solvent, were investigated by the controlled variable method. Under optimal conditions, the limit of detection (LODs) for the four targeted estrogens ranged from 0.06 to 0.15 µg/L, with a linear range from 0.2 to 100 µg/L. The observed enrichment factor (EF) ranged from 39 to 49, while the theoretical EF was estimated to be 50-fold. This methodology can be applied to the identification of estrogens in three environmental water samples.

Application of deep eutectic solvent based dispersive liquid–liquid microextraction method followed by HPLC-DAD for quantification of selected neonicotinoid pesticides in vegetable oils

The use of deep eutectic solvents (DES) as alternative green solvents in various analytical chemistry fields has garnered attention of researchers globally. Therefore, this study presents environmentally friendly DES for extraction of selected neonicotinoids (acetamiprid, imidacloprid, thiacloprid and thiamethoxam) prior to their determination using high-performance liquid chromatography- diode array detector (HPLC-DAD). The DES mixture that resulted in the highest extraction recoveries of neonicotinoids (NEOs) was choline chloride with ethylene glycol (CCl:EG) and nuclear magnetic resonance and Fourier transform infrared confirmed the successful synthesized CCl:EG. Thereafter, the CCl:EG was applied in dispersive liquid–liquid microextraction (DLLME) for the preconcentration and extraction of acetamiprid, imidacloprid, thiacloprid and thiamethoxam. The optimum factors affecting extraction efficiency of the DES-DLLME procedure were 0.8 mL (DES volume), 4.5 min (extraction time), 0.5 mL (eluent volume), 7 pH and 75 s (eluent time). The optimized DES-DLLME achieved limit of detection (LOD) and quantification (LOD) range of 0.4–4.95 ng.µL−1 and 1.43–9.70 ng.µL−1 respectively. Additionally, the extraction method achieved good accuracy (79.0–119.6 %), preconcentration factors (39.3–118), interday (0.61–1.62 %) and intraday (0.1–0.98 %) precisions. The greenness assessment of the proposed DES-DLLME method using AGREE, NEMI and AES tools revealed that the method was green. Finally, the developed DES-DLLME method was applied to real vegetable oils and the concentrations were below detection limits.

Development of a Rapid UPLC Method for Analysis of Carotenoids in Goji Berry Extract and Evaluation of Their Transformation Affected by Saponification.

Goji berry (Lycium barbarum L.), also known as wolfberry, is a traditional Chinese medicinal herb widely utilized as a functional food ingredient throughout East Asia. In this study, we developed a rapid high performance liquid chromatography-diode array detection (HPLC-DAD) method for the simultaneous separation of carotenoids in goji berries. This method successfully separates 17 carotenoids and their esters within 21 min using a Sunrise C30 column, with detection at 450 nm, a flow rate of 1.3 mL/min, and a column temperature of 25 °C. Method validation showed intra-day precision ranging from 0.97% to 6.21% and inter-day precision from 0.99% to 7.01%, demonstrating this method effectively minimizes analysis time while providing high separation efficiency and sensitivity. Goji berries extracted with a mixture of n-hexane/ethanol/acetone (1:1:1, v/v/v) and then saponified with a 40% potassium hydroxide methanol solution can completely convert carotenoid esters into free monomer forms. The highest carotenoid content in goji berry was all-trans-zeaxanthin (1721.94 ± 81.01 μg/g), followed by 9- or 9'-cis-zeaxanthin (79.53 ± 3.92 μg/g), 15- or 15'-cis-zeaxanthin (43.71 ± 2.17 μg/g), 9- or 9'-cis-zeaxanthin (36.51 ± 1.81 μg/g), all-trans-β-cryptoxanthin (25.76 ± 1.55 μg/g), all-trans-β-carotene (5.71 ± 0.83 μg/g), and 13- or 13'-cis-β-carotene (0.86 ± 0.13 μg/g).

Matrix Effect on a New Dispersive Liquid–Liquid Microextraction‐High‐Performance Liquid Chromatography–Diode Array Detection Method for the Determination of Efavirenz in Human Plasma

ABSTRACTA high‐performance liquid chromatography–diode array detection (HPLC‐DAD) method was developed and validated for the determination of efavirenz in human blood plasma samples from patients taking the antiretroviral drug. Results were compared with those previously obtained using gas chromatography/mass spectrometry (GC/MS) on the same sample extracts using dispersive liquid‐liquid microextraction. Validation of the HPLC‐DAD method yielded the United States Food and Drug Administration guidelines acceptable values. However, when validated, the accuracy using the HPLC‐DAD method was poor in contrast to GC/MS at the lower limit of quantification (LLOQ) level. The linearity of the HPLC‐DAD method was good with a coefficient of determination (R2) of 0.9922. The linear range of the calibration curve was 0.05–0.5 µg/mL. The LLOQ was 0.03 µg/mL at which spike level the accuracy was 8.9% (n = 3) and the precision was 8.3% (n = 3). Statistical analysis of the data showed that there were no systematic errors introduced in the HPLC‐DAD method but that there was a matrix effect that suppressed the signals and led to random error and subsequently impacted the accuracy of the results.

Effervescent-assisted Liquid-phase Microextraction Employing Switchable Hydrophilicity Solvent for the Determination of Cortisol and Testosterone in Oral Fluid by High-Performance Liquid Chromatography-Diode Array Detection.

Cortisol and testosterone are important biomarkers for diagnosing complex disorders, including polycystic ovary syndrome and Cushing's syndrome, where symptomatology usually overlaps with other prevalent disorders. This work proposes, for the first time, an analytical method based on a switchable hydrophilicity solvent as an extraction phase for the determination of cortisol and testosterone in oral fluid (OF) by high-performance liquid chromatography with diode-array detection. The optimized extraction conditions consisted of 1000µL of OF, 100µL of decanoic acid solution (65mg/mL), 170µL of Na2CO3, 900µL of H2SO4 and 150µL of acetonitrile for dilution. The method was validated, and coefficients of determination higher than 0.9926, the limit of detection of 4.55ng/mL and the limit of quantification of 15.00ng/mL were obtained. Intra-day precision varied from 5.6% to 11.9%, inter-day precision ranged from 6.1% to 13.5%, and relative recoveries ranged from 98.9% to 104.6% for cortisol, and 89.1% to 103.9% for testosterone. This methodology was successfully applied to five OF samples from volunteers. Moreover, the greenness of this methodology was evaluated based on the sample preparation metric of sustainability achieving a global score of 7.37 which can be considered sustainable.

Application of Fabric Phase Sorptive Extraction as a Green Method for the Analysis of 10 Anti-Diabetic Drugs in Environmental Water Samples

Due to the increased prevalence of diabetes, the consumption of anti-diabetic drugs for its treatment has likewise increased. Metformin is an anti-diabetic drug that is commonly prescribed for patients with type 2 diabetes and has been frequently detected in surface water and wastewaters, thus representing an emerging contaminant. Metformin can be prescribed in combination with other classes of anti-diabetic drugs; however, these drugs are not sufficiently investigated in environmental samples. Fabric phase sorptive extraction (FPSE) has emerged as a simple and green method for the extraction of analytes in environmental samples. In this study, FPSE coupled with a high-performance liquid chromatography diode array detector (HPLC-DAD) was employed for the simultaneous analysis of different classes of anti-diabetic drugs (metformin, dapagliflozin, liraglutide, pioglitazone, gliclazide, glimepiride, glargine, repaglinide, sitagliptin, and vildagliptin) in environmental water samples. Four different fabric membranes were synthesized but the microfiber glass filter coated with sol-gel polyethylene glycol (PEG 300) was observed to be the best FPSE membrane. The parameters affecting the FPSE process were optimized using a combination of one-factor-at-a-time processes and the design of experiments. The FPSE was evaluated as a green extraction method, based on green sample preparation criteria. The FPSE-HPLC-DAD method achieved acceptable validation results and was applied for the simultaneous analysis of anti-diabetic drugs in surface and wastewater samples. Glimepiride was detected below the quantification limit in both lake and river water samples. Dapagliflozin, liraglutide, and glimepiride were detected at 69.0 ± 1.0 μg·L−1, 71.9 ± 0.4 μg·L−1, and 93.9 ± 1.3 μg·L−1, respectively, in the city wastewater influent. Dapagliflozin and glimepiride were still detected below the quantification limit in city wastewater effluent. For the hospital wastewater influent, metformin and glimepiride were detected at 1158 ± 21 μg·L−1 and 28 ± 0.8 μg·L−1, respectively, while only metformin (392.6 ± 7.7 μg·L−1) was detected in hospital wastewater effluent.

Geographical origin identification of cinnamon using HPLC-DAD fingerprints and chemometrics

The commercial value of cinnamon depends largely on its geographical origin. This study proposed high-performance liquid chromatography-diode array detection (HPLC-DAD) fingerprints combined with chemometrics to identify geographical origins of cinnamons. Alternating trilinear decomposition (ATLD) algorithm was applied to extract meaningful chemical information from the HPLC fingerprint data. Then, non-targeted HPLC fingerprints and chemical component information were used as chemical descriptors to distinguish geographical origins using principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA)/N-way partial least squares-discriminant analysis (NPLS-DA). Satisfactory classification results were acquired for each discriminant model and the correct classification rates (CCRs) of training and test sets were 100%. Moreover, four characteristic variables were screened by variable importance in projection (VIP) method, three of which were reasonably identified as cinnamic acid, cinnamaldehyde and 2-methoxycinnamaldehyde, which can be regarded as potential markers to distinguish cinnamon from different geographical origins. The results indicated that HPLC-DAD fingerprints combined with chemometrics can be a promising means to identify the geographical origins and screen potential markers of cinnamon samples, especially in the absence of high-cost and sophisticated analytical instrumentals (e.g., high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy). This work can help to prevent cinnamon fraud practices and maintain the normal order of the cinnamon market.

Assessment of Veterinary Antibiotic Use and Occurrence of Veterinary Antibiotics in Livestock Manure from Farms in Rongai Sub-County, Kenya

Veterinary antibiotics are commonly used in livestock rearing to prevent diseases and stimulate growth. The release of antibiotics into the environment has become a significant environmental and public health concern. This research evaluated antibiotic use, livestock treatment, manure utilization, livestock waste treatment methods and antibiotic residues in livestock manure. Questionnaires were administered to 170 farmers rearing both cattle and poultry. Subsequently, 28 livestock manure samples from 15 cattle and 13 poultry rearing farms were collected from various farms to assess concentrations of tetracyclines (Tetracycline, Oxytetracycline) and sulfonamides (Sulfadiazine, Sulfamethoxazole) residues. Residues analysis was done using High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD). Veterinarians were the most preferred in treating both cattle and poultry in farms. Tetracyclines and sulfonamides were the most consumed class of antibiotics among both poultry and cattle rearing farmers. Compost manure and Biogas were the most preferred use of animal waste within farms. Antibiotic presence in samples was detected in 80% and 93% of cattle and poultry manure respectively. Maximum antibiotic concentrations of 16.24 and 15.18 (mg/kg) were recorded in poultry and cattle manure, respectively. There was a statistically significant difference in antibiotic concentrations in poultry and cattle manure (P<0.05). The results of this research are important in monitoring rising concerns about veterinary antibiotics on environmental and public health.

Cyanide profiling in stone fruit syrups: A comparative study of distillation techniques, a novel derivatization method, and cyanide composition in Maesil (Prunus Mume) syrup

Cyanide ion was derivatized with o-phthalaldehyde and 3-mercaptopropionic acid for high-performance liquid chromatography-diode array detector analysis. The structure was elucidated using nuclear magnetic resonance spectroscopy and ultra-high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry. Method validation was conducted for three distillation methods to analyze cyanogenic glycosides, cyanohydrins, and free cyanide in fruit syrup. Acid-aided distillation only detected free cyanide, while direct distillation detected both free cyanide and cyanohydrins, and enzyme-aided distillation reflected all three types. These approaches were applied to stone fruit syrups in South Korean markets and households. Among tested, maesil (Prunus mume) syrup contained the highest amount of total cyanide, reaching a maximum of 21.9 mg/kg (cyanide ion equivalent), compared to other syrups. Investigation of cyanide composition changes during maesil syrup production revealed that free cyanide occupies the lowest proportion. Cyanogenic glycosides degraded gradually during aging, while cyanohydrins remained the majority after 12 months aging.

A new approach for determination of urinary 8-hydroxy-2′-deoxyguanosine in cancer patients using reinforced solid/liquid phase microextraction combined with HPLC-DAD

AbstractThe concentration level of urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG), an oxidative stress biomarker for various diseases especially cancer, has been attracted as a pathway suitable for diagnostic purposes. Determination of urinary 8-OHdG is challenging due to its low level within a complex matrix. In this study, a new approach of solid/liquid phase microextraction technique prior to high-performance liquid chromatography diode-array detection (HPLC-DAD) analysis was developed for the determination of trace levels of 8-OHdG in urine samples. The solid/liquid phase microextraction device was constructed by reinforcement of multi-walled carbon nanotubes into the pores of a short segment 2.5 cm of hollow fiber microtube with two ends heat sealed. Based on the optimized procedure, the selected analyte was extracted from an acidic sample solution (10 mL adjusted at pH = 5) into the five extraction devices. After the extraction period (30 min), the 8-OHdG was eluted from the extraction device using methanol (350 µL) under ultrasonication for 5 min. The analytical performance of the method in synthetic urine samples showed good linearity (R2 > 0.999) with the limits of detection of 0.85 ng mL−1, and extraction recovery > 92.36%. The developed microextraction technique exhibited a confident sensitivity, feasible operation, and simplicity in comparison with other published methods and was valid to determinate trace 8-OHdG in urine cancer patients' samples by using a cheap and commonly available HPLC-DAD instrument.

Development of analytical method for determination of 1,3-dimethylamylamine in sports nutrition and bodybuilding supplements using pH-switchable deep eutectic solvents followed by high-performance liquid chromatography-diode array detector.

In this work, an easy, safe, simple, and efficient pH-switchable deep eutectic solvents (DESs)-based liquid phase microextraction followed by high-performance liquid chromatography-diode array detector analysis was developed for the determination of 1,3-dimethylamylamine (DMAA). The switchability of the obtained DESs was investigated by changing the pH. Then the best-selected DES was characterized and the application of the selected DES in the extraction of DMAA from sports nutrition and bodybuilding supplements was investigated. The DES synthesized from l-menthol: oleic acid in a molar ratio of 1:2 had the highest efficiency in the extraction of the target compound. Under the optimum conditions, (50µL of DES, 100µL of 4mol/L KOH, 100µL of 4mol/L HCl, extraction time of 40 s and without salt addition) the calibration graph was linear in the range of 0.05-100µg/kg and limit of detection was 0.02µg/kg. The relative standard deviations including intra-day and inter-day for 10.0µg/kg of DMAA in real samples were 2.7% (n=7) and 5.3% (n=7), respectively. The enrichment factor and percentage extraction recovery of the method were 283 and 85%, respectively. The relative recoveries for DMAA in different samples were in the range of 90%-109%.

Rapid mitragynine quantification and fingerprinting of products from Mitragyna speciosa Korth. leaf (Kratom) using high-performance thin-layer chromatography.

Kratom (leaves from Mitragyna speciosa Korth.; Rubiaceae) is a herbal medicine known for its analgesic properties and psychoactive effects. Kratom in Thailand is currently legal; however, it is prohibited in some countries and considered a narcotic plant. Our aim was to establish a reliable, simple, and rapid method for quantifying mitragynine in Kratom leaves and related products through a combination of high-performance thin-layer chromatography (HPTLC) and densitometry. A densitometric HPTLC method was developed and validated in terms of specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, and robustness. The fingerprints of kratom leaves, Mitragyna spp., and related products were constructed. For HPTLC, samples were applied to silica gel 60 F254 plates, and the mobile phase comprised n-hexane, ethyl acetate, and triethylamine (1:1:0.15, v/v/v). Densitometric detection was carried out under ultraviolet light at a wavelength of 226 nm. The validated method exhibited a range of 14.31-143.10 μg/mL, yielding a correlation coefficient of 0.9993. Spiked recovery rates were within a range of 98.3%-100.9%, and the LOD and LOQ were 3.80 and 11.53 μg/mL, respectively. Kratom samples were analyzed with the developed method, and the correlation coefficient was 0.9641, compared to the high-performance liquid chromatography-diode-array detection (HPLC-DAD) method. The HPTLC fingerprints displayed a distinctive pattern, facilitating discrimination among different plant parts and Mitragyna spp. The established method offers the advantages of simplicity, ease of use, and speed of analysis, serving as a practical alternative for mitragynine quantification in kratom leaf and its related products.

Adsorptive removal of organophosphate pesticides from aqueous solution using electrospun carbon nanofibers.

Organophosphate pesticides (OPPs) are widely prevalent in the environment primarily due to their low cost and extensive use in agricultural lands. However, it is estimated that only about 5% of these applied pesticides reach their intended target organisms. The remaining 95% residue linger in the environment as contaminants, posing significant ecological and health risks. This underscores the need for materials capable of effectively removing, recovering, and recycling these contaminants through adsorption processes. In this research, adsorbent materials composed of electro-spun carbon nanofibers (ECNFs) derived from polyacrylonitrile was developed. The materials were characterized through several techniques, including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) analysis, and contact angle measurements. SEM analysis revealed details of the structural properties and inter-fiber spacing variations of the carbon nanofibers. The results revealed that ECNFs possess remarkable uniformity, active surface areas, and high efficiency for adsorption processes. The adsorption studies were conducted using batch experiments with ethion pesticide in aqueous solution. High-Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) was utilized to quantify the concentrations of the OPP. Various parameters, including adsorbent dosage, pH, contact time, and initial ethion concentration, were investigated to understand their impact on the adsorption process. The adsorption isotherm was best described by the Freundlich model, while the kinetics of adsorption followed a non-integer-order kinetics model. The adsorption capacity of the ECNFs for OPP removal highlights a significant advancement in materials designed for environmental remediation applications. This study demonstrates the potential of ECNFs to serve as effective adsorbents, contributing to the mitigation of pesticide contamination in agricultural environments.

Dispersive solid phase extraction of some sulfonamide antibiotics from milk combined with dispersive liquid-liquid microextraction

A covalent organic framework based dispersive solid phase extraction was developed for extraction of several antibiotics from raw cow's milk samples. For this purpose, first, the milk proteins were precipitated by zinc sulfate and after centrifugation, the analytes were extracted by the sorbent. Then, the analytes were desorbed by a proper eluent and were more concentrated by a microextraction procedure. The extractant was used for the analysis of the analytes by high-performance liquid chromatography-diode array detector. Based on the results, acceptable extraction recoveries (62–71 %) and sensitive limits of detection and quantification in the ranges of 0.11–0.19 and 0.37–0.63 ng mL−1, respectively, were obtained. The method can analyze the analytes in broad concentration range. The introduced approach was used in the analysis of fifteen raw cow's milk samples. The obtained data showed that all samples were free of the analytes. According to these results, the method can be considered an efficient procedure for extracting the analytes from raw milk samples.

Phenolic profiles of Australian monofloral Eucalyptus, Corymbia, Macadamia and Lophostemon honeys via HPLC-DAD analysis

Australian honey samples from four botanical genera (Lophostemon, Eucalyptus, Macadamia and Corymbia) were investigated for their phenolic content. An improved phenolic extraction and high-performance liquid chromatography-diode array detection (HPLC-DAD) analysis method allowed for the rapid and reliable identification of phenolic compounds. A concentrated liquid-liquid extraction method with an acidified aqueous solution and acetonitrile was optimised to isolate phenolic compounds from the honey matrix. The concentrated extraction method improved sensitivity and permitted the identification of phenolics present at low concentrations (LOD: 0.012–0.25 mg/kg and LOQ: 0.040–2.99 mg/kg). The optimised HPLC-DAD chromatographic conditions gave stable retention times, improved peak separation and allowed for the inexpensive detection of each of the 109 phenolic compounds at their maximum absorbance wavelength. Out of the 109 phenolic compounds included in this study, 49 were identified in the Australian honeys tested. Furthermore, 25 of the 49 compounds were determined to be markers specific to honey floral origin.

Exploring Conventional and Green Extraction Methods for Enhancing the Polyphenol Yield and Antioxidant Activity of Hyssopus officinalis Extracts.

Hyssopus officinalis L. (HO) is, as one of the most prevalently utilized plants, used in traditional medicine to cure various diseases as well as the in food and cosmetic industries. Moreover, HO is a rich source of polyphenols with potent antioxidant properties. However, the studies on the extraction of such compounds from HO are scanty and sparse. This study aims to optimize the extraction of polyphenols and maximize the antioxidant activity in HO extracts. A comprehensive experimental design was employed, encompassing varied extraction parameters to determine the most effective ones. Alongside conventional stirring (ST), two green approaches, the ultrasonic treatment (US) and the pulsed electric field (PEF), were explored, either alone or in combination. The extracted polyphenolic compounds were identified with a high-performance liquid chromatography-diode array detector (HPLC-DAD). According to the results, the employment of ST along with an ethanolic solvent at 80 °C for 150 min seems beneficial in maximizing the extraction of polyphenols from HO, resulting in extracts with enhanced antioxidant activity. The total polyphenol was noted at 70.65 ± 2.76 mg gallic acid equivalents (GAE)/g dry weight (dw) using the aforementioned techniques, and the antioxidant activity was noted as 582.23 ± 16.88 μmol ascorbic acid equivalents (AAE)/g dw (with FRAP method) and 343.75 ± 15.61 μmol AAE/g dw (with the DPPH method). The as-prepared extracts can be utilized in the food and cosmetics industries to bestow or enhance the antioxidant properties of commercial products.