SWIEET-a salt-free alternative to QuEChERS.

The efficient extraction of various analytes from a wide spectrum of matrices with organic solvents is still a great challenge in analytical chemistry. Especially polar and charged compounds are hard to extract in combination with neutral analytes of intermediate to low polarity. The QuEChERS method is often chosen and has been adapted not only to the analysis of food samples, but also to environmental matrices (soil, wastewater) or biota. In this study, we overcome major drawbacks of QuEChERS such as low recoveries of charged analytes and impairment of downstream analysis by high salt loads. The new extraction method, applicable to liquid and solid samples, is called SWIEET (sugar water isopropanol ethyl nitrile extraction technique). Phase separation of the otherwise miscible extraction solvents water and acetonitrile is achieved by sugaring-out instead of salting-out. Extraction efficiencies were greatly improved by adding isopropanol to the acetonitrile phase. The concentrations of the additives glucose and isopropanol, as well as temperature, were optimized by a design of experiment. Further improvement was achieved through electro- or double-extractions. For all sample types tested (surface water, wastewater treatment plant effluent, tomato, soil, and oats), recoveries and precision were higher with SWIEET than with the established QuEChERS method. From wastewater treatment plant effluent, 75% recovery on average were achieved with our SWIEET method compared to 37% with QuEChERS for a model analyte mixture with polarities of logDpH7 = - 5.7 - 3.5. Higher recoveries and lower standard deviations compared to QuEChERS were achieved especially for polar and charged analytes such as metformin. Handling proved to be easy, since there was no additional solid phase and no tedious weighing of salts.

Determination of bisphenols in beeswax based on sugaring out-assisted liquid-liquid extraction: Method development and application in survey, recycling and degradation studies.

The methodology of sugaring out-assisted liquid-liquid extraction (SULLE) coupled with high-performance liquid chromatography-fluorescence detection was devised for quantifying bisphenol A (BPA) and bisphenol B (BPB) in beeswax. The effectiveness of SULLE was methodically explored and proved superior to the salting out-assisted liquid-liquid extraction approach for beeswax sample preparation. The analytical performance underwent comprehensive validation, revealing detection limits of 10 µg/kg for BPA and 20 µg/kg for BPB. The method developed was employed to analyse commercial beeswax (n = 15), beeswax foundation (n = 15) and wild-build comb wax (n = 26) samples. The analysis revealed BPA presence in four commercial beeswax samples and three beeswax foundation samples, with the highest detected residue content being 88 ± 7 µg/kg. For BPB, two beeswax foundation samples were positive, with concentrations below the limits of quantification and 85 ± 4 µg/kg, respectively. No bisphenols were detected in wild-build comb wax. Furthermore, the bisphenol removal efficacy of two recycling methods-boiling in water and methanol extraction-was assessed. The findings indicated that after four recycling cycles using water boiling, 9.6% of BPA and 29.2% of BPB remained in the beeswax. Whereas methanol extraction resulted in approximately 7% residual after one recycling process. A long-term study over 210 days revealed the slow degradation of bisphenols in comb beeswax. This degradation fitted well with a first-order model, indicating half-lives (DT50) of 139 days for BPA and 151 days for BPB, respectively. This research provides the first report on bisphenol contamination in beeswax. The low removal rate during the recycling process and the gradual degradation in beeswax underscore the significance of bisphenol contamination and migration in bee hives along with their potential risk to pollinators warranting concern. Furthermore, the developed SULLE method shows promise in preparing beeswax samples to analyse other analytes.

Homogeneous liquid-liquid microextraction coupled with HPLC/DAD for determination of nirmatrelvir and ritonavir as COVID-19 combination therapy in human plasma.

The study reports the development of a high-performance liquid chromatography/diode array detection method to measure the levels of nirmatrelvir and ritonavir in human plasma. These two antiviral medications are used for the treatment of COVID-19 and are marketed as Paxlovid®. The method employed sugaring-out induced homogeneous liquid-liquid microextraction to improve sensitivity. Optimization of the method was performed using the one variable at a time approach by adjusting several factors such as type of sugar, extractant, amount of sugar, volume of extractant, and pH of the aqueous sample to achieve the highest efficiency. The developed method was validated according to the Food and Drug Administration guidelines and demonstrated good linearity, accuracy, and precision. The range of linearity was from 1000 to 20,000 ng/mL for nirmatrelvir and 200 to 20,000 ng/mL for ritonavir with correlation coefficient values of 0.998 and 0.996, respectively. Selectivity studies revealed that no others peaks appeared in the retention times of the studied drugs. The stability of nirmatrelvir and ritonavir were also investigated through short term and three cycles of freeze-thaw, and both drugs were found stable. This analytical method could be useful for monitoring drug concentrations in patients undergoing treatment with these medications for COVID-19. In this work, for the first time, SULLME was used for the sensitive determination of nirmatrelvir and ritonavir in biological fluids. The developed method was able to determine both drugs in therapeutic levels with no need to sophisticated techniques like LC-MS. In addition to that, SULLME is considered a simple and green sample preparation in comparison with conventional sample preparation methods.

A Simple High-Throughput Field Sample Preparation Method Based on Matrix-Induced Sugaring-Out for the Simultaneous Determination of 5-Hydroxymethylfurfural and Phenolic Compounds in Honey.

In the present work, a high-throughput field sample preparation method was reported for the simultaneous determination of 5-hydroxymethylfurfural and phenolic compounds in honey. Combining a simple and green homogenous liquid−liquid extraction, matrix-induced sugaring-out, with the use of a 96-deepwell plate and multichannel pipette, the proposed method showed its merits in instrument-free and high-throughput preparation. Due to the high-throughput property, the parameters of the method were rapidly and systematically studied using a constructed 4 × 2 × 4 × 3 array (sample amount × ratio of ACN:H2O × standing time × replicates) in a 96-deepwell plate. Analytical performance was fully validated, and the limits of detection and limits of quantification were in the range of 0.17−1.35 µg/g and 0.51−4.14 µg/g, respectively. Recoveries were between 83.98 and 117.11%, and all the precisions were <5%. Furthermore, the developed method was successfully applied in the outdoor preparation of commercial honey samples and the in-field preparation of raw honey samples in apiary. The current work presented a simple, rapid, and high-throughput method for the field sample preparation of honey and provides a valuable strategy for the design of field and on-site sample preparation.

Determination of favipiravir in human plasma using homogeneous liquid-liquid microextraction followed by HPLC/UV.

Background: Favipiravir is an antiviral drug that was recently approved for the management of COVID-19 infection. Aim: This work aimed to develop a new method, using sugaring-out induced homogeneous liquid-liquid microextraction followed by HPLC/UV for the determination of favipiravir in human plasma. Materials & methods: The optimum extraction conditions were attained using 500 µl of tetrahydrofuran as an extractant and 1400 mg of fructose as a phase-separating agent. Results: The developed method was validated according to the US FDA bioanalytical guidelines and was found linear in the range of 25-80,000 ng/ml with a correlation coefficient of 0.999. Conclusion: These results showed that the developed method was simple, easy, valid and adequately sensitive for determination of favipiravir in plasma for bioequivalence studies.

Homogeneous liquid-liquid extraction as an alternative sample preparation technique for biomedical analysis.

Liquid-liquid extraction is a widely used technique of sample preparation in biomedical analysis. In spite of the high pre-concentration capacities of liquid-liquid extraction, it suffers from a number of limitations including time and effort consumption, large organic solvent utilization, and poor performance in highly polar analytes. Homogeneous liquid-liquid extraction is an alternative sample preparation technique that overcomes some drawbacks of conventional liquid-liquid extraction, and allows employing greener organic solvents in sample treatment. In homogeneous liquid-liquid extraction, a homogeneous phase is formed between the aqueous sample and the water-miscible extractant, followed by chemically or physically induced phase separation. To form the homogeneous phase, aqueous samples are mixed with water-miscible organic solvents, water-immiscible solvents/cosolvents, surfactants, or smart polymers. Then, phase separation is induced chemically (adding salt, sugar, or buffer) or physically (changing temperature or pH). This mode is rapid, sustainable, and cost-effective in comparison with other sample preparation techniques. Moreover, homogeneous liquid-liquid extraction is more suitable for the extraction of delicate macromolecules such as enzymes, hormones, and proteins and it is more compatible with liquid chromatography with tandem mass spectrometry, which is a vital technique in metabolomics and proteomics. In this review, the principle, types, applications, automation, and technical aspects of homogeneous liquid-liquid extraction are discussed.

Dispersive liquid-liquid microextraction method combined with sugaring-out homogeneous liquid-liquid extraction for the determination of some pesticides in molasses samples.

In this study, a sensitive analytical method was developed to determine some pesticides (cyprodinil, trifloxystrobin, prometryn, propachlor, fenitrothion, chlorpyrifos, profenofos, and phosalone) in molasses samples. Pesticides were extracted from samples by dispersive liquid-liquid microextraction method combined with sugaring-out homogeneous liquid-liquid extraction and determined by gas chromatography-mass spectrometry analysis. In this method, pesticides in molasses samples were first extracted using a water-miscible solvent (acetonitrile) in the sugaring-out homogeneous liquid-liquid extraction stage. The sugar in the ratio of 84-88% naturally contained in the molasses sample enabled phase separation in the acetonitrile-water homogeneous mixture. Then acetonitrile phase containing pesticides was used as dispersing solvent in the second step of the process. Under the specified optimum conditions, the limit of detection was calculated between 0.8-6.1 ng/g and the limit of quantification was in the range of 2.5-20 ng/g. The relative standard deviation values of molasses samples containing 150 ng/g of each analyte were found to be lower than 4.9% intra-day and 5.6% for inter-day. This validated method has been successfully applied to different types of molasses.

Sugaring-out induced homogeneous liquid-liquid microextraction as an alternative mode for biological sample preparation: A comparative study.

Miniaturization of liquid-liquid extraction is a growing field of sample preparation to reduce solvent consumption, protect the environment, and preserve operators' health. In this work, four different modes of liquid-liquid microextraction have been compared including dispersive liquid-liquid microextraction, binary and ternary salting-out, and sugaring-out induced liquid-liquid microextraction. The extraction efficiency was evaluated by the enrichment factors of 14 different drugs from three pharmacological classes. Compared with the other modes, sugaring-out induced liquid-liquid microextraction was found to be the most efficient and, thus, it was applied for sample preparation of the antivirals in human plasma. Method optimization was performed using response surface methodology for the sugar type and amount (in mg), the sample pH, the equilibration time (in min), and the extractant volume (in µL). The method was then validated and found linear in the concentration range of 0.10-10 µg/mL for daclatasvir, 0.05-10 µg/mL for velpatasvir, and 0.20-10 µg/mL for ledipasvir, with correlation coefficients in the range 0.996-0.999. These results shows that sugaring-out induced liquid-liquid microextraction could be a more efficient microextraction mode for preparation of biological samples. Compared with other types of microextraction, sugaring-out induced liquid-liquid microextraction is greener, simpler, and cost-effective, with less tendency to affect the sample pH.

Sugaring-out extraction of erythromycin from fermentation broth.

This study reports the sugaring-out extraction of erythromycin from fermentation broth using acetonitrile (ACN) as solvent and glucose as a mass separating agent. Different process parameters-glucose concentration, temperature, ACN/water ratio and pH-were optimized to achieve maximum extraction of erythromycin. 88% (w/w) of erythromycin was extracted from the model system with following optimized conditions: glucose 156.3 g/L; temperature 4 °C; ACN/water ratio 1 and pH 8.3. Further, the effect of typical fermentation media components (starch, soybean flour, CaCO3, NaCl and (NH4)2SO4) on sugaring out extraction of erythromycin was also investigated. Starch, soybean flour and CaCO3 were observed to affect erythromycin extraction only at higher concentration. Removal of suspended solids from simulated as well as real broth prior to extraction enhanced the extraction efficiency (from 72% to 87%). Sugaring out extraction of erythromycin was found to be more effective than salting out extraction. Also, higher partition coefficient was achieved in the present work than other reported methods using carbohydrates as mass separating agent. Further, it was found that the antimicrobial activity of erythromycin was preserved during sugaring out extraction of erythromycin.

Ionic liquid-based multi-stage sugaring-out extraction of lactic acid from simulated broth and actual lignocellulosic fermentation broth.

In this study, ionic liquid-based sugaring-out extraction was developed to separate lactic acid from the synthetic solution and actual lignocellulosic fermentation broth. Except for [EOHmim]BF4, the ILs with BF4- and OTF- anion can form aqueous two-phase system (ATPS) with the aid of saccharides. With the same kind of saccharides, the ATPS formation ability of ILs could be promoted by increasing the side-chain length of ILs in the order of [Hmim]BF4 ≈ [Bmim]BF4 ˃ [Emim]BF4 due to the decrease in ILs' kosmotropicity. On the other hand, for the same type of ILs, an ATPS was formed more easily with glucose than with xylose. When IL concentration varied from 35% (w/w) to 40% (w/w) at a low glucose concentration of 15% (w/w), an interesting phase reversal was observed. When lactic acid was undissociated at pH 2.0, 51.8% LA and 92.3% [Bmim]BF4 were partitioned to the top phase, and 97.0% glucose to the bottom phase using an ATPS consisting of 25% (w/w) glucose and 45% (w/w) IL. The total recovery of LA would increase to 89.0% in three-stage sugaring-out extraction from synthetic solution. In three-stage sugaring-out extraction from the filtered and unfiltered fermentation broth obtained via simultaneous saccharification and co-fermentation (SSCF) of acid-pretreated corn stover by the microbial consortium, the total recovery of LA was 89.5% and 89.8%, respectively. Furthermore, the total removal ratio of cells and pigments from the unfiltered broth was 68.4% and 65.4%, respectively. The results support IL-based sugaring-out extraction as a potential method for the recovery of lactic acid from actual fermentation broth.

An analytical strategy based on the combination of ultrasound assisted flat membrane liquid phase microextraction and a smartphone reader for trace determination of malondialdehyde.

In the present work, a new cleanup process entitled ultrasonic assisted flat membrane liquid phase microextraction (UA-FM-LPME) was introduced. The UA-FM-LPME procedure in two phase format was applied for the extraction-preconcentration of malondialdehyde (MDA) as an analyte model from the biological samples after a derivatization reaction. In the designed extraction setup, the simultaneous use of two flat sheet membranes and the application of ultrasonic radiation provided the efficient mass transfer of MDA into the acceptor phase in a short extraction time (2 min). The collected organic phase was then analyzed through Red-Green-Blue (RGB) image analysis and high-performance liquid chromatography coupled with ultraviolet-visible spectroscopy (HPLC-UV/Vis) as detection methods. The key parameters affecting the extraction process were studied and optimized in detail. The effect of the sugaring out on the partition of MDA into the extraction phase was examined for the first time. Under optimal conditions, linearity was observed in the concentration range of 8-1000 ng mL-1 for HPLC, and 10-1000 ng mL-1 for RGB analysis, with the coefficient of determination (R2) values higher than 0.9973. The introduced method also offered satisfactory relative standard deviations (RSDs) less than 4.0%. In order to examine the reliability of the technique in complicated matrices, three different biological samples (urine, saliva and blood plasma) were analyzed and the acceptable results in terms of relative recoveries (89.7-102.4%) were obtained. The designed setup in combination with RGB analysis will provide a low-cost alternative technique for rapid determination of MDA in clinical diagnosis or biochemical analysis without the need to complex, time consuming and expensive analytical instruments.

Matrix-Induced Sugaring-Out: A Simple and Rapid Sample Preparation Method for the Determination of Neonicotinoid Pesticides in Honey.

In the present work, we developed a simple and rapid sample preparation method for the determination of neonicotinoid pesticides in honey based on the matrix-induced sugaring-out. Since there is a high concentration of sugars in the honey matrix, the honey samples were mixed directly with acetonitrile (ACN)-water mixture to trigger the phase separation. Analytes were extracted into the upper ACN phase without additional phase separation agents and injected into the HPLC system for the analysis. Parameters of this matrix-induced sugaring-out method were systematically investigated. The optimal protocol involves 2 g honey mixed with 4 mL ACN-water mixture (v/v, 60:40). In addition, this simple sample preparation method was compared with two other ACN-water-based homogenous liquid-liquid extraction methods, including salting-out assisted liquid-liquid extraction and subzero-temperature assisted liquid-liquid extraction. The present method was fully validated, the obtained limits of detection (LODs) and limits of quantification (LOQs) were from 21 to 27 and 70 to 90 µg/kg, respectively. Average recoveries at three spiked levels were in the range of 91.49% to 97.73%. Precision expressed as relative standard deviations (RSDs) in the inter-day and intra-day analysis were all lower than 5%. Finally, the developed method was applied for the analysis of eight honey samples, results showed that none of the target neonicotinoid residues were detected.

Sugaring-out assisted electromembrane extraction of basic drugs from biological fluids: Improving the efficiency and stability of extraction system.

In the current study, for the first time, the sugaring-out effect was assessed in a conventional electromembrane extraction (EME) system. Utilizing the sugars in the donor solution as green additives can result in production of a pioneering and influential EME mode. Sugaring-out assisted electromembrane extraction was combined with high-performance liquid chromatography (HPLC) to enhance the extraction of four basic model drugs (pseudoephedrine, lidocaine, propranolol, and ketoconazole). In this mode of EME, not only the transfer of analytes through the supported liquid membrane (SLM) was improved, but also the whole extraction system became more stable than the conventional one in the same voltage. The type and concentration of sugars were optimized in addition to the common experimental parameters influencing the EME, and figures of merit were also studied. Under the optimum conditions, repeatability (RSD%) was obtained in the range of 2.8-6.9% in the water, while RSD value was obtained in the range of 8.2-11.8% (n = 3) for conventional EME with the same state. The linearity range was also in the interval of 5.0-1000.0 ng mL-1 and limits of quantification and detection were in the ranges of 5.0-10.0 ng mL-1 and 1.5-3.0 ng mL-1, respectively, in the introduced EME. Extraction recoveries in the range of 41.2 and 80.8% were obtained resulting in enrichment factors in the range of 96-189. In light of such factor, new suggested EME mode was assessed in the real biological samples including human plasma and urine in order to prove the sugaring-out efficiency in EME systems.

Sugaring-out assisted liquid-liquid extraction coupled with high performance liquid chromatography-electrochemical detection for the determination of 17 phenolic compounds in honey.

In this work, a simple sugaring-out assisted liquid-liquid extraction (SULLE) method coupled with high performance liquid chromatography-electrochemical detection (HPLC-ECD) has been developed for rapid and sensitive determination of 17 phenolic compounds in honey. To achieve the maximum extraction efficiency of target analytes, several parameters, such as pH, ionic strength, extraction times and the volume of extracting solvent were optimized. Chromatographic separation was performed on a C18 column with a gradient methanol/aqueous formic acid elution, and the ECD was set at 1.0 V in oxidative mode. Under the optimal conditions, good linearity was obtained for 17 phenolic compounds with the coefficients of determination (R2) higher than 0.9986 in the range of 0.05-20 µg mL-1. The limits of detection (LODs, S/N = 3) for the 17 phenolic compounds were in the range of 0.20-1.26 µg kg-1 by ECD, 9-83 times lower than those obtained with UV detection. Satisfactory recoveries between 79.8% and 105.7% were obtained for spiked honey samples with relative standard deviations (RSD) less than 5.1%. Compared with conventional LLE method, the proposed SULLE method provided higher extraction efficiency and had advantages of rapidity, ease of operation, much less consumption of organic solvents and samples. The proposed HPLC-ECD method featuring excellent sensitivity and selectivity has been applied to the quantification of phenolic compounds in honey samples of different floral origin.

Comparison of the Partition Efficiencies of Multiple Phenolic Compounds Contained in Propolis in Different Modes of Acetonitrile⁻Water-Based Homogenous Liquid⁻Liquid Extraction.

Homogeneous liquid⁻liquid extraction (HLLE) has attracted considerable interest in the sample preparation of multi-analyte analysis. In this study, HLLEs of multiple phenolic compounds in propolis, a polyphenol-enriched resinous substance collected by honeybees, were performed for improving the understanding of the differences in partition efficiencies in four acetonitrile⁻water-based HLLE methods, including salting-out assisted liquid⁻liquid extraction (SALLE), sugaring-out assisted liquid⁻liquid extraction (SULLE), hydrophobic-solvent assisted liquid⁻liquid extraction (HSLLE), and subzero-temperature assisted liquid⁻liquid extraction (STLLE). Phenolic compounds were separated in reversed-phase HPLC, and the partition efficiencies in different experimental conditions were evaluated. Results showed that less-polar phenolic compounds (kaempferol and caffeic acid phenethyl ester) were highly efficiently partitioned into the upper acetonitrile (ACN) phase in all four HLLE methods. For more-polar phenolic compounds (caffeic acid, p-coumaric acid, isoferulic acid, dimethoxycinnamic acid, and cinnamic acid), increasing the concentration of ACN in the ACN⁻H2O mixture could dramatically improve the partition efficiency. Moreover, results indicated that NaCl-based SALLE, HSLLE, and STLLE with ACN concentrations of 50:50 (ACN:H2O, v/v) could be used for the selective extraction of low-polarity phenolic compounds. MgSO4-based SALLE in the 50:50 ACN⁻H2O mixture (ACN:H2O, v/v) and the NaCl-based SALLE, SULLE, and STLLE with ACN concentrations of 70:30 (ACN:H2O, v/v) could be used as general extraction methods for multiple phenolic compounds.

Optimization of protein extraction from Chlorella Vulgaris via novel sugaring-out assisted liquid biphasic electric flotation system.

Microalgae biomass has been consumed as animal feed, fish feed and in human diet due to its high nutritional value. In this experiment, microalgae specie of Chlorella Vulgaris FSP-E was utilized for protein extraction via simple sugaring-out assisted liquid biphasic electric flotation system. The external electric force provided to the two-phase system assists in disruption of rigid microalgae cell wall and releases the contents of microalgae cell. This experiment manipulates various parameters to optimize the set-up. The liquid biphasic electric flotation set-up is compared with a control liquid biphasic flotation experiment without the electric field supply. The optimized separation efficiency of the liquid biphasic electric flotation system was 73.999 ± 0.739% and protein recovery of 69.665 ± 0.862% compared with liquid biphasic flotation, the separation efficiency was 61.584 ± 0.360% and protein recovery was 48.779 ± 0.480%. The separation efficiency and protein recovery for 5 × time scaled-up system was observed at 52.871 ± 1.236% and 73.294 ± 0.701%. The integration of simultaneous cell-disruption and protein extraction ensures high yield of protein from microalgae. This integrated method for protein extraction from microalgae demonstrated its potential and further research can lead this technology to commercialization.

Extraction of proteins from microalgae using integrated method of sugaring-out assisted liquid biphasic flotation (LBF) and ultrasound.

In this study, a simple sugaring-out supported by liquid biphasic flotation technique combined with ultrasonication was introduced for the extraction of proteins from microalgae. Sugaring-out as a phase separation method is novel and has been used in the extraction of metal ions, biomolecules and drugs. But, its functioning in protein separation from microalgae is still unknown. In this work, the feasibility of sugaring-out coupled with ultrasound for the extraction of protein was investigated. Primary studies were carried out to examine the effect of sonication on the microalgae cell as well as the separation efficiency of the integrated method. Effect of various operating parameters such as the concentration of microalgae biomass, the location of sonication probe, sonication time, ultrasonic pulse mode (includes varying ON and OFF duration of sonication), concentration of glucose, types of sugar, concentration of acetonitrile and the flow rate in the flotation system for achieving a higher separation efficiency and yield of protein were assessed. Besides, a large-scale study of the integration method was conducted to verify the consistency of the followed technique. A maximum efficiency (86.38%) and yield (93.33%) were attained at the following optimized conditions: 0.6% biomass concentration, 200 g/L of glucose concentration, 100% acetonitrile concentration with 5 min of 5 s ON/10 s OFF pulse mode and at a flow rate of 100 cc/min. The results obtained for large scale were 85.25% and 92.24% for efficiency and yield respectively. The proposed liquid biphasic flotation assisted with ultrasound for protein separation employing sugaring-out demonstrates a high production and separation efficiency and is a cost-effective solution. More importantly, this method provides the possibility of extending its application for the extraction of other important biomolecules.

Comparison of salting-out and sugaring-out liquid-liquid extraction methods for the partition of 10-hydroxy-2-decenoic acid in royal jelly and their co-extracted protein content.

Homogeneous liquid-liquid extraction (h-LLE) has been receiving considerable attention as a sample preparation method due to its simple and fast partition of compounds with a wide range of polarities. To better understand the differences between the two h-LLE extraction approaches, salting-out assisted liquid-liquid extraction (SALLE) and sugaring-out assisted liquid-liquid extraction (SULLE), have been compared for the partition of 10-hydroxy-2-decenoic acid (10-HDA) from royal jelly, and for the co-extraction of proteins. Effects of the amount of phase partition agents and the concentration of acetonitrile (ACN) on the h-LLE were discussed. Results showed that partition efficiency of 10-HDA depends on the phase ratio in both SALLE and SULLE. Though the partition triggered by NaCl and glucose is less efficient than MgSO4 in the 50% (v/v) ACN-water mixture, their extraction yields can be improved to be similar with that in MgSO4 SALLE by increasing the initial concentration of ACN in the ACN-water mixture. The content of co-extracted protein was correlated with water concentration in the obtained upper phase. MgSO4 showed the largest protein co-extraction at the low concentration of salt. Glucose exhibited a large protein co-extraction in the high phase ratio condition. Furthermore, NaCl with high initial ACN concentration is recommended because it produced high extraction yield for 10-HDA and the lowest amount of co-extracted protein. These observations would be valuable for the sample preparation of royal jelly.

Automated sugaring-out liquid-liquid extraction based on flow system coupled with HPLC-UV for the determination of procainamide in urine.

A fully automated sugaring-out assisted liquid-liquid extraction procedure was suggested. The procedure was based on the separation of the acetonitrile phase, containing a target analyte from the homogeneous sample solution after injection of sugaring-out reagent (glucose) into a mixing chamber of the flow system. Air bubbling was used to promote the extraction process and phase separation. After the fast phase separation in the mixing chamber, the acetonitrile phase containing the target analyte was transferred to an HPLC-UV system. Under the optimal conditions, the detector response of procainamide was linear in the concentration range of 6×10-7-4×10-5molL-1. The limit of detection, calculated from a blank test based on 3σ, was 2×10-7molL-1. The proposed method was successfully applied for the determination of procainamide in human urine samples and the analytical results agreed fairly well with the results obtained by reference CE method.

On-line in-syringe sugaring-out liquid-liquid extraction coupled with HPLC-MS/MS for the determination of pesticides in fruit and berry juices.

A fully automated method for the determination of pesticides (malathion, diazinon, imidacloprid and triadimefon) in fruit and berry juices has been developed. In the current study, the on-line in-syringe sugaring-out liquid-liquid extraction was successfully combined with a HPLC-MS/MS system for the first time. The procedure assumes the liquid-liquid extraction of analytes in water-miscible organic solvent acetonitrile followed by phase separation using glucose as sugaring-out reagent. After the phase separation in a syringe of a flow system, the extract containing pesticides was injected into the HPLC-MS/MS system. The proposed automated sample preparation procedure is rapid, simple, relatively inexpensive, and allows to avoid shortcomings of conventional liquid-liquid extraction, such as necessity to use nonpolar organic solvents, which are not always suitable for the HPLC-MS/MS detection. The conditions of pesticides' extraction such as ratio of acetonitrile/water, type and concentration of sugaring-out reagent, volume of sample and effect of pH have been studied and optimized. Under optimal experimental conditions the linear detection ranges were found to be 10-2-10mgL-1 for malathion and triadimefon, 10-3-10mgL-1 for diazinon, and 10-1-10mgL-1 for imidacloprid. The LODs, calculated from a blank test, based on 3σ, found to be 3·10-3mg L-1 for malathion and triadimefon, 3·10-4mg L-1 for diazinon and 3·10-2mgL-1 for imidacloprid. The application of the method has been demonstrated in the determination of these four pesticides in commercial samples of five fruit and berry juices. As an outcome, the analytical results agreed fairly well with the results obtained by a reference GC-FID method.