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This study pioneers a comparison of the application of biomimetic techniques, immobilised artificial membrane liquid chromatography (IAM LC) and liposome electrokinetic capillary chromatography (LEKC), for the prediction of pulmonary drug permeability. The pulmonary absorption profiles of 26 structurally unrelated drug-like molecules were evaluated using their IAM hydrophobicity index (CHI IAM) measured in IAM LC, and the logarithm of distribution constants (log KLEKC) derived from the LEKC experiments. Lipophilicity (phospholipids) parameters obtained from IAM LC and most LEKC analyses were linearly related to the n-octanol/water partitioning coefficients of the neutral forms (i.e., log Po/w values) to a moderate extent. However, the relationship with distribution coefficients at the experimental pH (7.4) (i.e., log D7.4) were weaker overall for IAM LC data and sigmoidal for some liposome compositions (phosphatidyl choline (PC): phosphatidyl inositol (PI) 85:15 mol% and 90:10 mol%) and concentrations (4 mM) in LEKC. This suggests that phospholipid partitioning supports both hydrophobic and electrostatic interactions occurring between ionised drugs and charged phospholipid moieties. The latter interactions are original when compared to those taking place in the more established n-octanol/water partitioning systems. A stronger correlation (R2 > 0.65) was identified between the LEKC retention parameters, and the experimental apparent lung permeability (i.e., log Papp values) as opposed to the values obtained by IAM LC. Therefore, LEKC offers unprecedented advantages over IAM LC in simulating cell membrane partitioning processes in the pulmonary delivery of drugs. Although LEKC has the advantage of more effectively simulating the electrostatic and hydrophobic forces in drug/pulmonary membrane interactions in vitro, the technique is unsuitable for analysing highly hydrophilic neutral or anionic compounds at the experimental pH. Conversely, IAM LC is useful for analysing compounds spanning a wider range of lipophilicity. Its simpler and more robust implementation, and propensity for high-throughput automation make it a favourable choice for researchers in drug development and pharmacological studies.

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Genetic factors, diet, lifestyle, and other factors lead to various complications in the body, such as obesity and other chronic diseases. The inflammatory state caused by excessive accumulation of body fat affects the pathways related to the control of glycemic homeostasis, leading to a high demand for insulin, to subsequent failure of stressed ß cells, and development of type 2 diabetes mellitus (T2DM). The study of new endocrine signalers, such as bile acids (BAs), becomes necessary as it allows the development of alternatives for T2DM treatment. In this work, a methodology was developed to quantify tauroursodeoxycholic BA (TUDCA) in liver cells of the HepG2 strain treated in hyperlipidic medium. This BA helps to improve insulin clearance by increasing the expression of the insulin-degrading enzyme, restoring sensitivity to this hormone, and making it viable for treating T2DM. Herein, a targeted metabolomic method for TUDCA determination in extracellular medium of hepatocyte matrices by micellar electrokinetic chromatography-UV was optimized, validated, and applied. The optimized background electrolyte was composed of 40 mmol/L sodium cholate and 30 mmol/L sodium tetraborate at pH 9.0. The following figures of merit were evaluated: linearity, limit of quantification, limit of detection, accuracy, and precision. Data obtained with the validated electrophoretic method showed a self-stimulation of TUDCA production in media supplemented only with BA. On the other hand, TUDCA concentration was reduced in the hyperlipidic medium. This suggests that, in these media, the effect of TUDCA is reduced, such as self-stimulated production and consequent regulation of glycemic homeostasis. Therefore, the results reinforce the need for investigating TUDCA as a potential T2DM biomarker as well as its use to treat several comorbidities, such as obesity and diabetes mellitus.

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The degradation of the diphenyl-ether herbicides aclonifen (ACL) and bifenox (BF) in water samples has been studied under different laboratory conditions, using in-tube solid-phase microextraction (IT-SPME) coupled to capillary liquid chromatography (capLC). The working conditions were selected in order to detect also bifenox acid (BFA), a compound formed as a result of the hydroxylation of BF. Samples (4 mL) were processed without any previous treatment, which allowed the detection of the herbicides at low ppt levels. The effects of temperature, light and pH on the degradation of ACL and BF have been tested using standard solutions prepared in nanopure water. The effect of the sample matrix has been evaluated by analysing different environmental waters spiked with the herbicides, namely ditch water, river water and seawater. The kinetics of the degradation have been studied and the half-life times (t1/2) have been calculated. The results obtained have demonstrated that the sample matrix is the most important parameter affecting the degradation of the tested herbicides. The degradation of both ACL and BF was much faster in ditch and river water samples, where t1/2 values of only a few days were observed. However, both compounds showed a better stability in seawater samples, where they can persist for several months. In all matrices ACL was found to be more stable than BF. In samples where BF had been substantially degraded, BFA was also detected, although the stability of this compound was also limited. Other degradation products have been detected along the study.

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The study aimed to develop a method for the separation of dispersed dyes extracted from polyester fibers. Nine commercially available disperse dyes, which were used to dye three polyester fabrics, were tested. Extraction of dyes from 1 cm long threads was carried out in chlorobenzene at 100 °C for 6 h. The separation was performed using microemulsion electrokinetic capillary chromatography (MEEKC) with photodiode array detection. Microemulsion based on a borate buffer with an organic phase of n-octane and butanol and a mixture of surfactants, sodium dodecyl sulphate and sodium cholate, were used. The addition of isopropanol and cyclodextrins to microemulsion resulted in a notable improvement in resolution and selectivity. The content of additives was optimized by using the Doehlert experimental design. Values of the coefficient of variance obtained in the validation process, illustrating the repeatability and intermediate precision of the migration times fit in the range of 0.11-1.24% and 0.58-3.21%, respectively. The developed method was also successfully applied to the differentiation of 28 real samples-polyester threads collected from clothing. The obtained results confirmed that proposed method may be used in the discriminant analysis of polyesters dying by disperse dyes and is promisingly employable in forensic practice.

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A novel, simple and efficient capillary electrophoresis method was developed to simultaneous determination of six furanocoumarins (psoralen, isopsoralen, imperatorin, isoimperatorin, phellopterin, and cnidilin). The separation buffer consisted of 30 mM boric acid, 12 mM sulfobutylether-ß-cyclodextrin and 1.5 mM 2-hydroxypropyl-ß-cyclodextrin (pH 7.8); the voltage was 20 kV, the temperature was 25 °C and the detection wavelength was at 246 nm with a diode array detector (DAD). Under the above conditions, the analytes could be separated with high resolution in less than 7 min. This method was used to simultaneously determine the content of psoralen, imperatorin, isoimperatorin and phellopterin in Angelica Dahurica Radix. And good linearities were obtained with correlation coefficients from 0.9992 to 0.9999. The limits of detection (LOD, S/N = 3) and the limits of quantitation (LOQ, S/N = 10) ranged from 0.6 to 3.0 µg/mL and from 2.1 to 9.9 µg/mL, respectively. The recoveries ranged between 98.8% and 101.8%. The results indicated the method can achieve baseline separation and quantitative analysis of furanocoumarins in Chinese herbal medicines and formulations.

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The applicability of micellar electrokinetic capillary chromatography (MEKC) with mass spectrometric detection for the determination of artemisinin and its analogs (e.g. ascaridole, artemisia ketone, casticin, deoxyartemisinin, arteannuic acid, artemetin, dihydroartemisinic acid) was studied. 40 mM ammonium perfluorooctanoate (pH 9.5) with 2% isopropanol (IPA) was used as background electrolyte (BGE) and the sheath liquid was 50 % (v/v) IPA:water containing 0.1 % formic acid. Separation was performed in a bare fused silica capillary. Artemisinin was detected at 283.1545 m/z as [M+H]+ ion. For artemisinin the linear range was found to be 0.6 µg/mL - 60 µg/mL and the limit of detection was 0.18 µg/mL. The RSD% values were 2.6 % for migration times and 4.8 % for peak areas (N = 6). In the ethanolic extracts of Artemisia annua leaves, in addition to artemisinin, a large number of other organic components could be separated and determined. MEKC-MS revealed the existence of diastereomers of several compounds (artemisinin, deoxyartemisinin, dihydroartemisinic acid) in the plant extracts.

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The research was done with partial filling micellar electrokinetic chromatography, microemulsion electrokinetic chromatography, and ultra-high performance liquid chromatography. The study focuses on determination of male and female steroids from cold and hot tap water of households in Helsinki City. The district´s raw water is made run from Päijänne Lake through a water tunnel to the purification plants in Helsinki area. The effluents delivered from the plants to households as tap water were sampled and used for the study. They were concentrated with solid phase extraction to exceed the detection limits of the three methods. With partial filling method the limits were 0.50, 0.48, 0.33, and 0.50 mg/L for androsterone, testosterone, progesterone, and testosterone-glucuronide, respectively. In microemulsion method the limit values were 1.33, 1.11, and 0.40 mg/L for androsterone, testosterone, and progesterone, respectively, and 0.83, 0.45, and 0.50 mg/L for hydrocortisone, 17-α-hydroxyprogesterone, and 17-α-methyltestosterone, respectively. In the tap water samples, progesterone concentrations represented the highest values being 0.22 and 1.18 ng/L in cold and hot water, respectively. They also contained testosterone (in all samples), its glucuronide metabolite (in 25% of the samples), and androstenedione (in 75% of the samples). The ultra-high liquid chromatographic method with mass spectrometric detection was used for identification of the steroids at µg/L level.

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In this study, a simple and sensitive cyclodextrin-modified mixed micellar electrokinetic capillary chromatography (CD-MEKC) method has been developed for the simultaneous separation and determination of Huperzine A (HupA), Huperzine B (HupB) and Huperzine C (HupC) in Huperzia serrata (H. serrata). The optimal conditions (pH 9.3) were composed of 10 mM sodium tetraborate solution, 40 mM sodium dodecyl sulfate (SDS), 50 mM sodium cholate (SC) and 3.0 mM mono-(6-ethylenediamine-6-deoxy)-ß-cyclodextrin (ED-ß-CD). The separation and determination process were performed on a P/ACE MDQ capillary electrophoresis system, the separation voltage was 15 kV, the temperature was 25 °C and the detection wavelength was 308 nm. Under the optimum conditions, the migration time was less than 9 min. The LOD and LOQ were between 0.38 and 0.80 µg/mL and 1.2-2.3 µg/mL, respectively. The developed method, with excellent precision and accuracy, was applied for the determination of three alkaloids in H. serrata and its formulations.

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OBJECTIVE: To establish a micellar electrokinetic capillary chromatography-based method for identification and quantitative detection of interleukin-12 (IL-12) and analysis of its unfolding process. METHODS: An uncoated fused-silica capillary (inner diameter 50 µm) with a total length of 48.5 cm (40 cm to the detector) was used for the experiment. The factors influencing the separation efficiency of IL-12 were analyzed, and a standard curve of IL-12 concentration was established. The mixture of IL-12 and anti-IL-12 antibody was incubated in a water bath at 38 ℃ for 40 min, and capillary electrophoresis was then performed under the same conditions. The results were compared with those of IL-12 and anti-IL-12 antibody to identify IL-12. IL-12 and dithiothreitol (DTT) were incubated at 60 ℃ in water bath for different lengths of times, and the unfolding process of IL-12 was analyzed based on electrophoresis results of IL-12 in different states. RESULTS: A micellar capillary electrophoresis on-line sweep method was established with 80 mmol/L borate (pH=9.3) containing 30 mmol/L sodium dodecyl sulfate (SDS) as the buffer solution. This system showed a good linear relationship between the peak area and the mass concentration of IL-12 with a linear correlation coefficient of 0.9991 within the linear range of 2 to 120 ng/L. As the incubation time of IL-12 and DTT prolonged, the disulfide bond of IL-12 gradually opened and resulted in distinct changes in the protein peak. CONCLUSIONS: This capillary electrophoresis-based method is simple and sensitive for IL-2 analysis and allows rapid detection of changes in IL-12 content in the setting of tumors and analysis of the possible causes.

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A micellar electrokinetic capillary chromatography (MEKC) method with ultraviolet visible (UV) detection was used for the determination of 1,7-naphthalenediol, 2,3-naphthalenediol, 1,5-naphthalenediol, and 2,7-naphthalenediol in cosmetics. The current method for their determination in various cosmetics is high-performance liquid chromatography (HPLC). Separation conditions affecting the MEKC method were optimized as 20 mM Na2 B4 O7 -50mM SDS, pH 9.8, with 22 kV applied voltage and UV detection at 230 nm. Under optimal conditions, electrophoretic analysis was completed in less than 6 min, with limit of detection (LOD) of 0.070-0.19 µg/mL and limit of quantitation (LOQ) of 0.23-0.63 µg/mL. A good linear relationship (r2 > 0.99) was obtained at the range of 0.75-20 µg/mL. Recoveries for the four naphthalenediols in lotion, loose powder, and sun cream are between 91.2-107.2% with relative standard deviation (RSD) less than 4.04%. The method has been successfully applied to the determination of the four naphthalenediols in different kinds of cosmetics. A comparison with HPLC-UV method was also carried out according to the National Standards of the People's Republic of China. The results obtained by MEKC and HPLC methods are comparable, but the proposed MEKC method can help us obtain a much shorter detection time and low cost.

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A simple and sensitive salting out-assisted dispersive liquid-liquid microextraction method using deep eutectic solvent combined with back extraction and micellar electrokinetic capillary chromatography (SO-DLLME-DES-BE-MECC) was developed for the determination of fluoroquinolones in milk, honey and water samples. Several parameters affecting the extraction efficiency including DES volume, vortex time, centrifugation time, salt type and amount, sample pH and volume, etc. were investigated. Good linearity were obtained for fluoroquinolones in a range of 0.020-3.200 µg mL-1 and 0.030-4.800 µg mL-1 with LODs less than 0.010 µg mL-1. The recoveries were in the ranges of 95.0-104.9%, 90.1-110.2% and 87.8-114.1% for water, honey and milk samples, respectively. The relative standard deviations for reproducibility were all below 7.6%. Under the optimized conditions, the enrichment factors for analytes were achieved in the range from 531 to 858 folds. The presented method was successfully applied for the determination of fluoroquinolones in milk, honey and water samples.

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Caffeine (CA) is a common xanthine alkaloid found in tea leaves, coffee beans, and other natural plants, and is the most widely used psychotropic substance in the world. Accumulating evidence suggests that low plasma levels of CA and its metabolites may serve as reliable diagnostic markers for early Parkinson's disease (PD) patients. In this study, we demonstrated a new MEKC method for determining CA and its three main downstream metabolites, paraxanthine (PX), theobromine (TB), and theophylline (TP), in human plasma. Plasma samples were collected, and analyzed using MEKC, after SPE. The running buffer was composed of 35 mM phosphate, pH of 10.5, and 25 mM SDS. The separation voltage was 15 kV and the detection wavelength was at 210 nm. Under the optimum conditions, four distinct analytes were completely separated and detected in less than 12 min. Method limits of detection were as low as 7.5 ng/mL for CA, 5.0 ng/mL for TB, and 4.0 ng/mL for both PX and TP. The recoveries were between 88.0% and 105.9%. This method was successfully applied to 27 human plasma samples. The results indicate that the plasma concentrations of the four analytes are significantly lower in patients with early PD than in control subjects (p < 0.05). The area under curve was improved to 0.839 when CA and its three main metabolites were included, suggesting that MEKC testing of CA, TP, TB, and PX may serve as a potential method for early diagnosis of PD.

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Fipronil is an insecticide that is not approved in the European Union in food. In 2017, fipronil was involved in a European health alert due to its presence in fresh hen eggs because of an illicit use in poultry farms, so reliable methods are needed to determine fipronil and its main metabolites in these matrixes. In this work, we report the first approach to the study of fipronil and two metabolites, fipronil-sulfone and fipronil-sulfide by CE. MEKC mode was employed using a solution of 50 mM ammonium perfluorooctanoate pH 9.0 with 10% (v/v) methanol as background electrolyte. The proposed method was combined with a simple sample treatment based on salting-out assisted LLE (SALLE) using acetonitrile as extraction solvent and ammonium sulfate as salt. The SALLE-MEKC-UV method allowed the simultaneous quantification of fipronil and fipronil-sulfone. Validation parameters yielded satisfactory results, with precision, expressed as relative SD, below 14% and recoveries higher than 83%. Limits of detection were 90 µg/kg for fipronil and 150 µg/kg for fipronil-sulfone, so in terms of sensitivity further studies of sample treatments allowing extra preconcentration or the use of more sensitive detection, such as MS, would be needed.

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Conventional gas chromatography - mass spectrometry (GC-MS) takes 20-40 min per sample, which is undesirably slow in any application if speed can be increased while still meeting analytical needs. In this study, we achieved reasonably good separations with full analysis cycle times of less than 1 min by combining for the first time low-pressure (LP) GC-MS with low thermal mass (LTM) resistive-heating for rapid temperature ramping and cooling of the capillary column. The analytical column is threaded into the LTM thin-walled metal tubing in an instrumental device known as "LTM Fast GC" that is mounted at the top of the gas chromatograph in a detector port. The column inlet and outlet are connected to the GC injector and MS transfer line as usual. For LPGC-MS, a 40 cm, 0.1 mm. i.d. uncoated flow restrictor capillary connected at the injector is coupled with a 2.6 m, 0.25 mm i.d., 0.25 µm film thickness analytical column leading to the MS. Thus, the inlet operates at normal GC pressures, but the analytical column is under vacuum, which increases the optimal helium carrier gas flow velocity thereby increasing speed of full range separations while maintaining acceptable quality of chromatography. This column configuration in LTM-LPGC-MS trades a 64-fold gain in speed of analysis vs. standard GC-MS for a 4-fold loss in chromatographic peak capacity, thereby converting analysis time from minutes into seconds in common applications. For example, jet fuel containing fatty acid methyl esters (akin to biofuel) was separated in 25 s with <1 min full analysis cycle time. An EPA Method 8270 mixture of 76 analytes was also analyzed in <1 min full cycle time by LTM-LPGC-MS. Other examples include very fast analysis of heroin in a street drug powder and elucidation of a new organic synthetic compound. In this report, we describe and discuss the several advantageous and practical features of LTM-LPGC-MS, as well as its trade-offs.

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INTRODUCTION: Hirsutine and hirsuteine are the main pharmacological activity ingredients of Uncaria rhynchophylla (UR), playing an important role in treating mental and cardiovascular diseases, such as Alzheimer's disease, hypertension, Parkinson's disease, potential anti-cancer activities and so on. OBJECTIVE: To develop a cyclodextrin-modified micellar electrokinetic capillary chromatography (CD-MEKC) method for the simultaneous separation and determination of hirsutine and hirsuteine from UR and its formulations. METHODOLOGY: The optimal method was developed by investigating influences of significant factors on the separation, and this method was successfully applied for the determination of hirsutine and hirsuteine in UR and its formulations. RESULTS: The optimal background electrolyte (BGE) consisted of 40 mM sodium dihydrogen phosphate (pH 7.0), 150 mM 2,6-dimethyl-ß-cyclodextrin (DM-ß-CD), 3 mM mono-(6-ethylenediamine-6-deoxy)-ß-cyclodextrin (ED-ß-CD), and 30 mM sodium cholate (SC). Under these conditions, hirsutine and hirsuteine were successfully separated within 13 min at the separation voltage of 15 kV, temperature of 25°C and the detection wavelength of 224 nm. For the analytes, linear calibration curves were performed within the range 5.0-160.0 µg/mL. The limit of detection (LOD, S/N = 3) and the limit of quantitation (LOQ, S/N = 10) were 0.41, 1.42 µg/mL for hirsutine and 0.60, 2.17 µg/mL for hirsuteine, respectively. The recoveries of three samples were from 97.9% to 102.3%. CONCLUSION: The method was successfully applied to the determination of hirsutine and hirsuteine in UR and its formulations. Meanwhile, it provides an effective reference of the quality control of UR and its formulations.

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Improvements in sample preparation, separation, and mass spectrometry continue to expand the coverage in LC-MS based lipidomics. While longer columns packed with smaller particles in theory give higher separation performance compared to shorter columns, the implementation of this technology above commercial limits has been sparse due to difficulties in packing long columns and successfully operating instruments at ultrahigh pressures. In this work, a liquid chromatograph that operates up to 35 kpsi was investigated for the separation and identification of lipid species from human plasma. Capillary columns between 15-50 cm long were packed with 1.7 µm BEH C18 particles and evaluated for their ability to separate lipid isomers and complex lipid extracts from human plasma. Putative lipid class identifications were assigned using accurate mass and relative retention time data of the eluting peaks. Our findings indicate that longer columns packed and operated at 35 kpsi outperform shorter columns packed and run at lower pressures in terms of peak capacity and numbers of features identified. Packing columns with relatively high concentration slurries (200 mg/mL) while sonicating the column resulted in 6-34% increase in peak capacity for 50 cm columns compared to lower slurry concentrations and no sonication. For a given analysis time, 50 cm long columns operated at 35 kpsi provided a 20-95% increase in chromatographic peak capacity compared with 15 cm columns operated at 15 kpsi. Analysis times up to 4 h were evaluated, generating peak capacities up to 410 ±â€¯5 (n = 3, measured at 4σ) and identifying 480 ±â€¯85 lipids (n = 2). Importantly, the results also show a correlation between the peak capacity and the number of lipids identified from a human plasma extract. This correlation indicates that ionization suppression is a limiting factor in obtaining sufficient signal for identification by mass spectrometry. The result also shows that the higher resolution obtained by shallow gradients overcomes possible signal reduction due to broader, more dilute peaks in long gradients for improving detection of lipids in LC-MS. Lastly, longer columns operated at shallow gradients allowed for the best separation of both regional and geometrical isomers. These results demonstrate a system that enables the advantages of using longer columns packed and run at ultrahigh pressure for improving lipid separations and lipidome coverage.

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OBJECTIVE: To establish a method for analysis of related substances in biapenem with micellar electrokinetic capillary chromatography(MEKC). METHODS: In order to improve the separation selectivity, a zwitterionic surfactant, 3-(N, N-dimethylhexadecylammonium)-propanesulfonate(PAPS) was used. The optimal separation conditions were as follows: the total length of the capillary was 48.5 cm (the effective length was 48 cm), the buffer was 90 mmol•L-1 tris(hydroxymethyl)aminomethane (tris)-phosphate buffer containing 17 mmol•L-1 PAPS and 3 mg•mL-1 polyoxyethylene 23 lauryl ether (Brij 35), the applied voltage was 22 kV, and the capillary temperature was controlled at 30℃. Further more, the specificity, linearity, precision, repeatability, stability and durability were studied. The contents of related substances in biapenem commercial samples were analyzed. RESULTS: The MEKC method, which was a comparable analysis method to HPLC, successfully separated the adjacent impurities of biapenem by using the zwitterionic surfactant PAPS. The specific test showed that this method was especially suitable for the detection of biapenem dimers A, B and open-ring compound. CONCLUSION: In this method, MEKC with zwitterionic surfactant is for the first time applied to the analysis of related substances in biapenem (amphoteric drugs). It provides a feasible analysis method with high sensitivity, good specificity and reproducibility for the quality control of biapenem.

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OBJECTIVE@#To establish a micellar electrokinetic capillary chromatography-based method for identification and quantitative detection of interleukin-12 (IL-12) and analysis of its unfolding process.@*METHODS@#An uncoated fused-silica capillary (inner diameter 50 μm) with a total length of 48.5 cm (40 cm to the detector) was used for the experiment. The factors influencing the separation efficiency of IL-12 were analyzed, and a standard curve of IL-12 concentration was established. The mixture of IL-12 and anti-IL-12 antibody was incubated in a water bath at 38 ℃ for 40 min, and capillary electrophoresis was then performed under the same conditions. The results were compared with those of IL-12 and anti-IL-12 antibody to identify IL-12. IL-12 and dithiothreitol (DTT) were incubated at 60 ℃ in water bath for different lengths of times, and the unfolding process of IL-12 was analyzed based on electrophoresis results of IL-12 in different states.@*RESULTS@#A micellar capillary electrophoresis on-line sweep method was established with 80 mmol/L borate (pH=9.3) containing 30 mmol/L sodium dodecyl sulfate (SDS) as the buffer solution. This system showed a good linear relationship between the peak area and the mass concentration of IL-12 with a linear correlation coefficient of 0.9991 within the linear range of 2 to 120 ng/L. As the incubation time of IL-12 and DTT prolonged, the disulfide bond of IL-12 gradually opened and resulted in distinct changes in the protein peak.@*CONCLUSIONS@#This capillary electrophoresis-based method is simple and sensitive for IL-2 analysis and allows rapid detection of changes in IL-12 content in the setting of tumors and analysis of the possible causes.

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In-line coupling of capillary columns is an effective means for achieving miniaturized and automated separation methods. The use of multimodal column designed to allow the direct integration of a sample preparation step to the separation column is one example. Herein we propose a novel in-line coupling at the capillary scale between a boronate affinity capillary column (µBAMC unit) and a reversed-phase separation column. This has been made possible due to the elaboration of a new and efficient µBAMC unit. A thiol-activated silica monolithic capillary column was functionalized through thiol-ene photoclick reaction. This simple and fast reaction allows to prepare stable µBAMC units having grafting densities of 1.93 ± 0.17 nmol cm-1. This grafting strategy increases the surface density by a factor 4 compared to our previous strategies and opens the frame to in-line coupling with reversed-phase capillary column. Proof of concept of the in-line coupling was done by coupling a 1-cm length µBAMC unit to a 7-cm length reversed phase capillary column. The conditions of loading, elution and separation were optimized for cis-diol nucleosides analysis (uridine, cytidine, adenosine, guanosine). A loading volume (at pH 8.5) of up to 21 hold volume (i.e 1 µl) of the µBAMC unit can be loaded without sample breakthrough. For the least retained nucleoside (uridine) a limit of detection of 50 ng mL-1 was estimated. Elution and full separation of the four nucleosides was triggered by flushing the multimodal column with an acetic acid (50 mM) / methanol (98/2, v/v) mobile phase.

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A new functionalized polymer monolithic capillary with a macrocyclic antibiotic, namely colistin sulfate, as chiral selector was prepared via the copolymerization of binary monomer mixtures consisting of glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA) in porogenic solvents namely 1-propanol and 1,4-butanediol, in the presence of azobisiso-butyronitrile (AIBN) as initiator and colistin sulfate. The prepared capillaries were investigated for the enantioselective nano-LC separation of a group of racemic pharmaceuticals, namely, α- and ß-blockers, anti-inflammatory drugs, antifungal drugs, norepinephrine-dopamine reuptake inhibitors, catecholamines, sedative hypnotics, antihistaminics, anticancer drugs, and antiarrhythmic drugs. Acceptable separation was achieved for many drugs using reversed phase chromatographic conditions with no separation achieved under normal phase conditions. Colistin sulfate appears to be useful addition to the available macrocyclic antibiotic chiral phases used in liquid chromatography.

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