Novel Binary Solvents-Dispersive Liquid—Liquid Microextraction (BS-DLLME) Method for Determination of Patulin in Apple Juice Using High-Performance Liquid Chromatography

Effects of Pretreatments on Patulin Removal from Apple Juices Using Lactobacilli: Binding Stability in Simulated Gastrointestinal Condition and Modeling

Recently, researchers have reported the presence of patulin as a mycotoxin in commercial apple products, especially apple juices. The aim of this study was to assess adsorption of patulin from artificially contaminated apple juice using two lactic acid bacteria (LAB) strains of Lactobacillus acidophilus ATCC 4356 and Lactobacillus plantarum ATCC 8014. Furthermore, effects of five physical and chemical pretreatments on the patulin adsorption were investigated. Results demonstrated that patulin adsorption abilities of both strains increased with NaOH pretreatment but decreased after autoclaving. The NaOH-treated L. plantarum ATCC 8014 showed the best removal rate (59.74%) after 48 h of refrigerated storage, compared with the NaOH-treated L. acidophilus ATCC 4356 (52.36%). Moreover, stability of the LAB-patulin complex was assessed in simulated gastrointestinal tract conditions and a low quantity of patulin was released into the solution. The patulin adsorption process by NaOH-treated L. plantarum ATCC 8014 followed Freundlich isotherm model and pseudo-second-order kinetic model. Fourier transform infrared spectroscopy showed that polysaccharide and protein components of the L. plantarum ATCC 8014 cell wall played key roles in patulin adsorption. The major functional groups of the cell wall that were involved in adsorbing patulin included -OH/-NH, -CH₂, C=O, and C-O groups. The current results suggest that NaOH-treated L. plantarum ATCC 8014 cells include the potential to detoxify patulin-contaminated apple juices.

A miniaturized spray-assisted fine-droplet-formation-based liquid-phase microextraction method for the simultaneous determination of fenpiclonil, nitrofen and fenoxaprop-ethyl as pesticides in soil samples

RATIONALE

Pesticides are a group of micropollutants that persist for a long time in the environment and pose threats to life. Much effort has been devoted to developing pre-concentration methods capable of producing samples suitable for the detection of pesticides. However, better methods are still required to detect these compounds when they are present in trace concentrations in soils.

METHOD

Spray-assisted fine-droplet-formation-based liquid-phase microextraction was used to prepare soil samples containing three different pesticides, fenpiclonil, nitrofen and fenoxaprop-ethyl, for subsequent analysis by gas chromatography/mass spectrometry (GC/MS). A spraying apparatus was used for the dispersion of the extraction solvent into the sample/standard solution to improve the extraction efficiency. Optimization studies were performed to lower the detection limits of these analytes and the results obtained by the application of the newly developed system were compared with those obtained using the conventional GC/MS method.

RESULTS

A calibration curve over the range 5.0-100 μg L^-1 was obtained under the optimal conditions. The limits of detection and quantification were 1.56-1.80 μg L^-1 and 5.21-5.98 μg L^-1 , respectively. The enhancements in detection ability over the conventional method for the three tested pesticides were 188.01, 176.96 and 517.14 for fenpiclonil, nitrofen and fenoxaprop-ethyl, respectively Recovery studies performed in soil samples were satisfactory reflecting accurate applicability of the developed method.

CONCLUSIONS

The developed microextraction method is a time-saving and simple version of the traditional dispersive liquid-liquid microextraction method that also reduces the use of dispersive solvents.

The ability of Lactobacillus rhamnosus to bind patulin and its application in apple juice

The purpose of this study was to evaluate the ability of Lactobacillus rhamnosus to bind patulin (PAT) in the buffer solution and apple juice. The binding of L. rhamnosus to PAT was reversible, which improved the stability of the bacterial complex. The ability to bind PAT can be enhanced with the inactivation of the strain by high temperature and acid treatment. Acid-treated bacteria had the highest PAT binding rate of 72.73±1.05%. The binding rates of acid and high temperature (121 °C) treatments were increased by 21.37% and 19.15%, respectively. L. rhamnosus showed the best detoxification ability to PAT at 37 °C, where the binding rate reached 50.9±1.03%. When the dose of inactivated bacteria powder was 0.02 g ml−1, the minimum concentration of PAT in apple juice was 0.37 µg ml−1. The addition of the L. rhamnosus inactivated powder did not affect the quality of the juice product and effectively bound the PAT in apple juice.

Binary Dispersive Liquid-Liquid Microextraction Strategy for Accurate and Precise Determination of Micropollutants in Lake, Well and Wastewater Matrices

In this study, a binary mixture in dispersive liquid-liquid microextraction was used for the preconcentration and determination of selected pesticides, pharmaceutical and hormone by GC-MS. A Box-Behnken experimental design was used to optimize the amounts of binary mixture, dispersive solvent and salt. The optimum parameters obtained were dichloromethane/1,2-dichloroethane binary mixture (200 µL), ethanol (2.0 mL) and potassium nitrate (1.0 g). Analytical performance of each analyte was determined under the optimum conditions and the lowest and highest detection limits calculated were 0.43 and 5.9 ng/mL. Low relative standard deviations were obtained even in the lowest concentrations in linear calibration plots, signifying high precision for the sample preparation procedure and instrumental measurement. Accuracy of the developed method and applicability to real samples was tested on well, lake, hospital and municipal wastewater. The percent recoveries acquired at different spiked concentrations were satisfactory (89%-108%), validating the accuracy of the method for the quantification of the analytes in the selected matrices.

Rapid extraction of copper ions in water, tea, milk and apple juice by solvent-terminated dispersive liquid-liquid microextraction using p-sulfonatocalix (4) arene: optimization by artificial neural networks coupled bat inspired algorithm and response surface methodology

A bat inspired algorithm with the aid of artificial neural networks (ANN-BA) has been used for the first time in chemistry and food sciences to optimize solvent-terminated dispersive liquid-liquid microextraction (ST-DLLME) as a green, fast and low cost technique for determination of Cu²⁺ ions in water and food samples using p-sulfonatocalix (4) arene as a complexing reagent. For this purpose, the influence of four important factors four factors which was influenced on the extraction efficiency such as salt addition, solution pH and disperser and extraction solvent volumes were investigated. Central composite design (CCD) as a comparative technique was employed for optimization of ST-DLLME efficiency. The ANN-BA optimization technique was regarded as a superior model due to its higher value of extraction efficiency (about 7.21%) compared to CCD method. Under ANN-BA optimal conditions, the limit of quantitation (S/N = 10), limit of detection (S/N = 3) and linear range were 0.35, 0.12 and 0.35-1000 µg L^-1, respectively. In these circumstances, the percentage recoveries for drinking tea, apple juice, milk, bottled drinking water, river and well water spiked with 0.05, 0.1 and 0.2 mg L^-1 of Cu²⁺ ions were in the acceptable range (91.4-107.1%). In comparison to other methods, the developed ST-DLLME method showed the lowest solvent and sample consumption, shortest value of extraction time, most suitable determination and detection limits and linear range with simple and low cost apparatus. Additionally, the use of bat inspired algorithm as a powerful metaheuristic algorithm with the aid of artificial networks is another advantage of the present work.

Simultaneous extraction of Cu2+ and Cd2+ ions in water, wastewater, and food samples using solvent-terminated dispersive liquid-liquid microextraction: optimization by multiobjective evolutionary algorithm based on decomposition

Solvent-terminated dispersive liquid-liquid microextraction (ST-DLLME) as a simple, fast, and low-cost technique was developed for simultaneous extraction of Cd²⁺ and Cu²⁺ ions in aqueous solutions. Multiobjective evolutionary algorithm based on decomposition with the aid of artificial neural networks (ANN-MOEA/D) was used for the first time in chemistry, environment, and food sciences to optimize several independent variables affecting the extraction efficiency, including disperser volume and extraction solvent volume, pH, and salt addition. To perform the ST-DLLME operations, xylene, methanol, and dithizone were utilized as an extraction solvent, disperser solvent, and chelating agent, respectively. Non-dominated sorting genetic algorithm versions II and III (NSGA II and NSGA III) as multiobjective metaheuristic algorithms and in addition central composite design (CCD) were studied as comparable optimization methods. A comparison of results from these techniques revealed that ANN-MOEA/D model was the best optimization technique owing to its highest efficiency (97.6% for Cd²⁺ and 98.3% for Cu²⁺). Under optimal conditions obtained by ANN-MOEAD, the detection limit (S/N = 3), the quantitation limit(S/N = 10), and the linear range for Cu²⁺ were 0.05, 0.15, and 0.15-1000 μg L^-1, respectively, and for Cd²⁺ were 0.07, 0.21, and 0.21-750 μg L^-1, respectively. The real sample recoveries at a spiking level of 0.05, 0.1, and 0.3 mg L^-1 of Cu²⁺ and Cd²⁺ ions under the optimal conditions obtained by ANN-MOEA/D ranged from 94.8 to 105%.

Dispersive liquid-liquid microextraction for rapid and inexpensive determination of tetramethylpyrazine in vinegar

The concentration of tetramethylpyrazine (TMP) in vinegar is an active indicator of vinegar quality. Dispersive liquid-liquid microextraction (DLLME) was first applied to vinegar as a clean-up pre-treatment for the rapid (5 min) determination of TMP by high-pressure liquid chromatography with ultraviolet detection (HPLC-UV), and may serve as an alternative to solid-phase extraction (SPE) or solid-phase microextraction (SPME). High sensitivity of HPLC for TMP determination was obtained using the DLLME pretreatment, with a limit of detection (LOD) of 0.001 mg L^-1 and limit of quantification (LOQ) of 0.005 mg L^-1. The developed method exhibited excellent linearity in the concentration range of 0.050-80.000 mg L^-1, with a correlation coefficient R² > 0.999. Furthermore, the percentage recovery of TMP in vinegar using the developed method was within the range 97.97-105.24%. Therefore, DLLME coupled with HPLC-UV is a sensitive and promising method for vinegar clean-up and TMP assay.

Synthesis of Fe3O4@CuS@Ni2P-CNTs magnetic nanocomposite for sonochemical-assisted sorption and pre-concentration of trace Allura Red from aqueous samples prior to HPLC-UV detection: CCD-RSM design

A simple procedure based on ultrasound-assisted (UA) dispersive micro solid phase extraction (D-μ-SPE) was applied for sorption of trace amount Allura Red (AR) in fruit juice and water samples. After loading process by UA-D-μ-SPE, the concentrated AR was eluted and monitored using high-performance liquid chromatography-ultraviolet -visible detector (HPLC-UV). The best operational conditions were obtained as follows: pH = 3.0, 8 mg of the sorbent, sonication time of 4.5 min and 0.16 mL of THF as elution solvent. Under the optimum operational conditions, the present method was acceptable for AR quantification in the range of 1.0-5000 ng mL^-1. The repeatability based on RSD with the amount of 1.67-3.18%, low LOD (0.198 ng mL^-1) and LOQ (0.659 ng mL^-1) were obtained. The UA-D-μ-SPE-HPLC-UV method was successfully applied for trace quantification of AR from water and commercial fruit juice samples supplied from local supermarkets, and acceptable relative recoveries over the range of 97.7-105.4% with RSDs ≤5.50% were obtained.

Optimization of Solvent Terminated Dispersive Liquid-Liquid Microextraction of Copper Ions in Water and Food Samples Using Artificial Neural Networks Coupled Bees Algorithm

A multivariate method based on solvent terminated dispersive liquid-liquid microextraction was developed for the determination of Cu²⁺ ions in aqueous samples. In the proposed approach, di-2-ethylhexylphosphoric acid, xylene and acetone were used as chelating agent, dispersive and extraction solvents, respectively. The effects of various factors on the extraction efficiency such as extraction and dispersive solvent volumes, salt addition and pH were studied using central composite design (CCD) and artificial neural networks coupled bees algorithm (ANN-BA). Upon comparison of these techniques, ANN-BA model was considered to be better optimization method due to its higher percentage relative recovery (about 5%) as compared to the CCD approach. The linear range and the limits of detection (S/N = 3) and quantitation (S/N = 10) were 0.22-140, 0.08 and 0.22 µg L^-1, respectively. Under the optimal conditions, the recoveries for real samples spiked with 0.1 and 0.3 mg L^-1 were in the range of 85-98%.

Patulin contamination in apple products marketed in Shiraz, Southern Iran

Background and Purpose:

Patulin is one of the important mycotoxins, produced by a wide range of molds, including Penicillium, Aspergillus, and Bysochlamys. Patulin is mainly found in the rotten parts of fruits and vegetables, such as apples, pears, peach, apricots, and grapes. Currently, the Codex Alimentarius and Food and Drug Administration have recommended a maximum level of 50 µg/L patulin for apple products. The purpose of this study was to investigate patulin contamination of apple juice and cans in 75 samples collected from 15 manufacturers in Shiraz, southern Iran.

Materials and Methods:

The detection of patulin was accomplished using a high-performance liquid chromatography with an ultraviolet detector.

Results:

A total of 38 apple juice samples (53%) and 17 apple cans (45%) were contaminated with patulin. Overall 50% and 3% of the apple juice and apple cans samples had a patulin level of > 3 µg/L.

Conclusion:

Although the maximum level of patulin in our samples was considerably lower than the permitted level established by the European Union (i.e., 50 µg/L), the high incidence of this mycotoxin in our samples should be lessen by improving their good manufacturing practice.

Determination of trace patulin in apple-based food matrices

Patulin is a toxic metabolite of a number of fungi; its toxicity is serious and its contamination in food is a worldwide problem, especially in apple-based food. Effective control of patulin contamination strongly depends on reliable analytical methods. In this review, various analytical methods, especially those that have appeared in the last ten years, are summarized, including the highly reproducible chromatography and mass-spectrometry-based methods, highly selective sensor-based methods and indirect quantitative PCR methods. This review also summarizes the promising features of novel materials in sample preparation for patulin determination.

Analysis of chlorpheniramine in human urine samples using dispersive liquid-liquid microextraction combined with high-performance liquid chromatography

A simple and environmentally friendly microextraction technique was used for determination of chlorpheniramine (CPM), an antihistamine drug, in human urine samples using dispersive liquid-liquid microextraction (DLLME) followed by high performance liquid chromatography with diode array detection (HPLC-DAD). In this extraction technique, an appropriate mixture of acetonitrile (disperser solvent) and carbon tetrachloride (extraction solvent) was rapidly injected into the urine sample containing the target analyte. Tiny droplets of extractant were formed and dispersed into the sample solution and then sedimented at the bottom of the conical test tube by centrifugation. Under optimal conditions, the calibration curve was linear in the range of 0.055-5.5 µg mL-1, with a detection limit of 16.5 ng mL-1. This proposed method was successfully applied to the analysis of real urine samples. Low consumption of toxic organic solvents, simplicity of operation, low cost and acceptable figures of merit are the main advantages of the proposed technique.

Binary Solvents Dispersive Liquid-Liquid Microextraction (BS-DLLME) Method for Determination of Tramadol in Urine Using High-Performance Liquid Chromatography

BACKGROUND

Tramadol is an opioid, synthetic analog of codeine and has been used for the treatment of acute or chronic pain may be abused. In this work, a developed Dispersive liquid liquid microextraction (DLLME) as binary solvents-based dispersive liquid-liquid microextraction (BS-DLLME) combined with high performance liquid chromatography (HPLC) with fluorescence detection (FD) was employed for determination of tramadol in the urine samples. This procedure involves the use of an appropriate mixture of binary extraction solvents (70 μL CHCl3 and 30 μL ethyl acetate) and disperser solvent (600 μL acetone) for the formation of cloudy solution in 5 ml urine sample comprising tramadol and NaCl (7.5%, w/v). After centrifuging, the small droplets of extraction solvents were precipitated. In the final step, the HPLC with fluorescence detection was used for determination of tramadol in the precipitated phase.

RESULTS

Various factors on the efficiency of the proposed procedure were investigated and optimized. The detection limit (S/N = 3) and quantification limit (S/N = 10) were found 0.2 and 0.9 μg/L, respectively. The relative standard deviations (RSD) for the extraction of 30 μg L of tramadol was found 4.1% (n = 6). The relative recoveries of tramadol from urine samples at spiking levels of 10, 30 and 60 μg/L were in the range of 95.6 - 99.6%.

CONCLUSIONS

Compared with other methods, this method provides good figures of merit such as good repeatability, high extraction efficiency, short analysis time, simple procedure and can be used as microextraction technique for routine analysis in clinical laboratories.

Developments in mycotoxin analysis: an update for 2012-2013

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2012 and mid-2013. It covers the major mycotoxins: aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone. A wide range of analytical methods for mycotoxin determination in food and feed were developed last year, in particular immunochemical methods and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS)-based methods. After a section on sampling and sample preparation, due to the rapid spread and developments in the field of LC-MS/MS multimycotoxin methods, a separate section has been devoted to this area of research. It is followed by a section on mycotoxins in botanicals and spices, before continuing with the format of previous reviews in this series with dedicated sections on method developments for the individual mycotoxins.

A validated dispersive liquid-liquid microextraction method for extraction of ochratoxin A from raisin samples

A method based on dispersive liquid-liquid microextraction (DLLME) was developed for the quantitative extraction of Ochratoxin A (OTA) from raisin samples. The influence of various parameters on the recovery of OTA such as type and volume of DLLME extractant, centrifuging and sonication time, also volume of deionized water was investigated. Recovery values under the optimum conditions were between 68.6 and 85.2 %, the inner and intra-day precision expressed as relative standard deviation (RSD%, n = 3), were less than 15 % at spiking levels of 2.5-30 μg kg(-1). Linearity was studied from 0.5 to 30 μg L(-1), and the limits of detection (LOD) and quantification (LOQ) were 0.7 and 2.0 μg kg(-1), respectively. Real samples were analyzed by DLLME method and compared with confirmative immunoaffinity Column Chromatography (IAC) clean-up. Low cost, simplicity of operation, speed and minimum consumption of organic solvent were the main advantages of proposed method. The mean contamination of samples was 0.88 μg kg(-1) that was lower than European Legal Limit.