Determination of 35 sulfonamides in pork by magnetic molecularly imprinted polymer-based dispersive solid-phase extraction and ultra-performance liquid chromatography photodiode array method.

BACKGROUND: Sulfonamide residues in foods of animal origin are potential risks to consumer health, so it is very important to inspect them. Among the previously reported instrumental methods, the best method can only be used to determine at most 22 sulfonamides. Thus, an instrumental method capable of determining more sulfonamide species is desirable. RESULTS: In this study, sulfadoxine was used as a template to synthesize a type of magnetic molecularly imprinted polymer that could recognize 35 sulfonamides. After characterization, this composite was used to develop a dispersive solid-phase extraction method for extraction and purification of the 35 sulfonamides in pork, followed by determination using an ultra-performance liquid chromatography photodiode array method. This composite exhibited high adsorption capacity (11.01-19.21 µg mg-1 ) and high recovery (>89.01%), and could be reused at least ten times. Due to the enrichment effect during sample preparation (enrichment factor 22-66), the limits of detection for determination of the 35 drugs in pork were in the range of 0.08-0.53 ng g-1 . The detection results for some real pork samples were consistent with a liquid chromatographic-tandem mass spectrometric method. After comparison, the present method showed generally better performances than the previously reported sample preparation methods and instrumental methods for detection of sulfonamides. CONCLUSION: The method developed in the present study could be used as a practical tool for routine detection of sulfonamide residues in pork samples. © 2022 Society of Chemical Industry.

A microtitre chemiluminescence sensor for detection of pyrethroids based on dual-dummy-template molecularly imprinted polymer and computational simulation.

The residues of pyrethroids in foods of animal origin are dangerous to the consumers, so this study presented a chemiluminescence sensor for determination of pyrethroids in chicken samples. A dual-dummy-template molecularly imprinted polymer capable of recognizing 10 pyrethroids was synthesized. The results of computation simulation showed that the specific 3D conformations of the templates had important influences on the polymer' recognition ability. The polymer was used to prepare a sensor on conventional 96-well microplates, and the sample solution was added into the wells for direct absorption. The absorbed analytes were initiated with the bis(2,4,6-trichlorophenyl)oxalate-H2 O2 -imidazole system, and the chemiluminescence intensity was used for analyte quantification. Results showed that one assay was finished within 12 min, and this sensor could be reused four times. The limits of detection for the 10 analytes were in the range o0.3-6.0 pg/ml, and the recoveries from the standards of fortified blank chicken samples were in the range 70.5-99.7%.

Determination of sulfonamides in meat with dummy-template molecularly imprinted polymer-based chemiluminescence sensor.

In this study, a molecularly imprinted polymer capable of recognizing 15 sulfonamides was first synthesized with sulfabenz as the dummy template. The calculation results from computation simulation showed that the specific 3D conformation of the template had an important influence on the polymer's recognition ability. Then, the polymer was used as recognition reagent to prepare a chemiluminescence sensor on a conventional 96-well microplate for the determination of the residues of 15 sulfonamides in meat (chicken and pork). Due to the 4-(imidazol-1-yl)phenol-enhanced luminol-H2O2 system, the limits of detection for the 15 analytes were in the range of 1.0-12 pg/mL. The recoveries from the standard fortified blank samples were in the range of 72.7-99%. Furthermore, one assay could be finished within 30 min, and the sensor could be reused 4 times. Therefore, this sensor could be used as a very useful tool for routine screening of residues of sulfonamides in meat samples. Graphical abstract Assay procedures of the molecularly imprinted polymer-based chemiluminescence sensor for determination of sulfonamides.

A molecularly imprinted polymer based chemiluminescence array sensor for one-step determination of phenothiazines and benzodiazepines in pig urine.

The residues of phenothiazines and benzodiazepines in foods of animal origin are dangerous to consumers. For inspection of their abuses, this study for the first time reported on the use of a chemiluminescence array sensor for the simultaneous determination of four phenothiazines and five benzodiazepines in pig urine. Two molecularly imprinted polymers were coated in different wells of a conventional 96-well microtiter plate as the recognition reagents. After sample loading, the absorbed analytes were initiated directly by using an imidazole enhanced bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide system to emit light. The assay process consisted of only one sample-loading step prior to data acquisition, so one test was finished within 10 min. The limits of detection for the nine drugs in the pig urine were in a range of 0.1 to 0.6 pg/mL, and the recoveries from the fortified blank urine samples were in a range of 80.3 to 95%. Furthermore, the sensor could be reused six times. Therefore, this sensor could be used as a simple, rapid, sensitive and reusable tool for routine screening for residues of phenothiazines and benzodiazepines in pig urine.

Molecularly imprinted polymer based microtiter chemiluminescence array for determination of phenothiazines and benzodiazepines in pork.

In this study, a molecularly imprinted polymer based chemiluminescence array capable of simultaneous determining phenothiazines and benzodiazepines was first reported. Two polymers were coated in different wells of the conventional 96-well microtiter plate as the recognition reagents, and the added analytes competed with a horseradish peroxidase-labeled bi-hapten conjugate to bind the recognition reagents. The light signal was induced by using a highly effective luminol-H2O2-IMP system. The assay procedure consisted of only one sample-loading step prior to data acquisition. Then, the array was used to determine 4 phenothiazines and 5 benzodiazepines in pork simultaneously. The limits of detection for the 9 drugs were in a range of 0.001-0.01 ng/mL, and the recoveries from the fortified blank pork were in a range of 63.5%-94.1%. Furthermore, the array could be reused for 8 times. The detection results for some real pork samples were consistent with an ultra performance liquid chromatography method.

[Treatment of hyperlipoidemia by xiaozhi capsule: a clinical efficacy research].

OBJECTIVE: To observe the clinical effect and efficacy of Xiaozhi Capsule (XZC), a Chinese medicine preparation for tonifying Gan-Shen, invigorating Pi to dissipate dampness (TGSIPDD) on total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and endothelin (ET) in treating patients with hyperlipidemia. METHODS: Totally 120 primary hyperlipidemia patients were randomly assigned to the treatment group (80 cases) and the control group (40 cases). Those in the treatment group took XZC, while those in the control group took Xuezhikang Capsule (XZKC). The serum TC, TG, HDL-C, LDL-C, and ET were detected and evaluated after 8 weeks of treatment. RESULTS: In the treatment group TC was reduced by 25.60%, TG by 33.70%, LDL-C by 32.90%, and ET by 11.02%, while HDL-C was elevated by 24.20%. In the control group, TC was reduced by 24.80%, TG by 33.50%, LDL-C by 31.30%, and ET by 12.05%, while HDL-C was elevated by 20.90%. There was statistical difference in the two groups when compared with before treatment (P < 0.01). But there was no statistical difference in the aforesaid indices between the two groups after treatment (P > 0.05). The integrals for main symptoms after treatment obviously decreased in the two groups, showing statistical difference when compared with before treatment in the same group (P < 0.01). But there was no statistical difference in the aforesaid indices between the two groups (P > 0.05). After 8 weeks of treatment, symptoms such as vertigo, heavy sensation of head, palpitation, chest distress, dry mouth and thirsty were obviously improved after treatment. There was statistical difference in the improvement of tinnitus after treatment in the treatment group (P < 0.01). The total effective rate was 86.25% in the treatment group and 82.50% in the control group, showing no statistical difference (P > 0.05). CONCLUSIONS: XZC showed certain effects on each blood lipid index and ET of hyperlipidemia patients. It had better improvement of clinical symptoms with reliable efficacy.

[Optimization of the matrix formulation of compound Die Da Zhen Tong cataplasm by uniform design].

OBJECTIVE: To optimize the matrix formulation of compound Die Da Zhen Tong cataplasm. METHODS: The optimal preparation was selected by U17 (17(16)) uniform design, independent variables were the percentage ratio of the matrix formulation component part in compound Die Da Zhen Tong cataplasm,and the viscosity, continued viscosity and overall desirability used as indexes were dependent variables. RESULTS: The percentage of the matrix formulation component part in compound Die Da Zhen Tong cataplasm was, NP-700: carbomer 980: PVP K-90: dihydroxy aluminum: tartaric: kaolinite: sorbitol: glycerin = 5: 1. 2: 2.5: 0.25: 0.15:4: 12: 5. CONCLUSION: The optimized cataplasm has good viscosity, continued viscosity and high overall desirability.

Structural stability of a polyetheretherketone femoral component-A 3D finite element simulation.

BACKGROUND: Because its mechanical properties are similar to cortical bones of the knee, polyetheretherketone (PEEK) material has been used to make total knee arthroplasty (TKA) components. This study investigated the PEEK femoral component deformation of a TKA system and compared the data with that of a cobalt-chromium (CoCr) component. METHODS: A 3D finite element knee model was constructed using CT images of a normal subject. A knee prosthesis was installed on the model to simulate a TKA knee. The material properties of the bone were assumed linear and transverse isotropic. The femoral component was modeled using a PEEK or CoCr material. A compressive load was applied to the knee at full extension. Tibiofemoral contact stresses and femoral component deformations were analyzed. FINDINGS: Under a 3 kN load, the maximal Von-Mises stresses in the femoral component were 14.39 MPa and 30.05 MPa for the PEEK and CoCr components, respectively. At the tibial polyethylene surface, the CoCr femoral component caused higher contact stresses (>2.2%) than the PEEK component. The deformation of the PEEK component was over 3 times larger than that of the CoCr component (0.65 × 10-3 mm vs 0.2 × 10-3 mm). INTERPRETATION: The PEEK femoral component could result in lower contact stresses, but larger deformations in the TKA knee compared to the CoCr component. An increased deformation of the PEEK component indicates a reduction in its structural strength. Future investigation should examine if the reduced structural strength will affect the in-vivo component-bone interface integration and affect the component fatigue life.

Detection of chloramphenicol in chicken, pork and fish with a molecularly imprinted polymer-based microtiter chemiluminescence method.

In this study, 4-nitrotoluene (NT) was used as dummy template to synthesize a molecularly imprinted polymer that was highly specific for chloramphenicol. The polymer was coated in the wells of 96-well microplates as recognition reagent to develop a chemiluminescence method. The analyte solution and an enzyme-labelled hapten were added into the wells to perform competition, and the light signal was induced with a highly efficient luminol-H2O2-4-(imidazol-1-yl)phenol system. Then, the optimized method was used to determine chloramphenicol in meat (chicken, pork and fish), and the limit of detection (LOD) was 5.0 pg g-1. Furthermore, the polymer-coated plate could be reused four times, and one test could be finished within 20 min. The recoveries from the standard fortified blank meat samples were in the range of 71.5-94.4%. Therefore, this method could be used as a useful tool for routine screening the residue of chloramphenicol in meat samples.

Dummy molecularly imprinted polymer based microplate chemiluminescence sensor for one-step detection of Sudan dyes in egg.

The objective of this study is to report a molecularly imprinted polymer-based chemiluminescence method for determination of Sudan dyes. A dummy-template molecularly imprinted polymer capable of recognizing seven Sudan dyes was first synthesized and its recognition mechanism was studied by using computation simulation method. The polymer was coated in the wells of conventional microplate to prepare a chemiluminescence sensor and the assay process consisted of only one sample-loading step prior to signal acquisition. The optimized sensor was used to determine the seven dyes in egg yolk and the results were confirmed with a high performance liquid chromatography. Results showed that this sensor achieved ultrahigh sensitivity (1.0-5.0 pg/mL), rapid assay process (10 min) and satisfactory recovery (70.5%-92.2%). Furthermore, the sensor could be reused for 5 times. Therefore, this sensor could be used as a useful tool for screening the residues of Sudan dyes in egg.

Preparation of a chemiluminescence sensor for multi-detection of benzimidazoles in meat based on molecularly imprinted polymer.

In this study, a molecularly imprinted polymer capable of recognizing 8 benzimidazoles was first synthesized. The computation simulation showed that the shape and size of used template were the main factors influencing its recognition ability. Then the polymer was used as recognition reagent to prepare a chemiluminescence sensor on conventional 96-well microplate. The sample solution and a HRP-labeled hapten were added into the microplate wells to perform competitive binding, and the light signal was initiated with 4-(imidazol-1-yl)phenol enhanced luminol-H2O2 system. The optimized sensor was used to determine the residues of 8 benzimidazoles in mutton and beef. Result showed that the sensor achieved ultrahigh sensitivity (limits of detection of 1.5-21 pg/mL), rapid assay process (18 min) and satisfactory recovery (65.8%-91.2%). Furthermore, this sensor could be reused for 4 times. Therefore, this sensor could be used as a rapid, simple, sensitive and durable tool for screening the residual benzimidazoles in meat.

A chitosan-based flocculant prepared with gamma-irradiation-induced grafting.

A natural polymer, chitosan, was modified to prepare an efficient flocculant using grafting method initiated by gamma ray in acid-water solution. A vinyl monomer, acrylamide, was used as the grafted monomer. The graft copolymer obtained was characterized using Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis. Effects of acetic acid concentration, total irradiation dose, dose rate and monomer concentration on the grafting percentage were investigated. Flocculation experiment results demonstrated that the graft copolymer produced was significantly superior to chitosan and polyacrylamide (PAM).

Analysis of adsorption characteristics of 2,4-dichlorophenol from aqueous solutions by activated carbon fiber.

In this study experiments were conducted to investigate the adsorption of 2,4-dichlorophenol (2,4-DCP) by activated carbon fiber (ACF) activated by static air. With the results of batch experiments at various temperatures, the adsorption isotherms, kinetics and thermodynamics of this adsorption process were evaluated. Four adsorption isotherm models, Langmuir, Freundlich, Redlich-Peterson and Toth equations, were used to fit the experimental data and the results reveal that the adsorption isotherm models fitted the data in the order of: Langmuir>Redlich-Peterson>Toth>Freundlich isotherms. A pseudo second-order adsorption model was better to describe the adsorption data than the pseudo first-order model and the Bangham model at the temperatures tested. The activation energy was calculated to be 40.90 kJ/mol, while the thermodynamic parameters DeltaH and DeltaS were estimated to be -5.82 kJ/mol and 0.07 kJ/(molK), respectively.

Dummy template molecularly imprinted polymer for solid phase extraction of phenothiazines in meat based on computational simulation.

The 3D structures of two dummy templates and four phenothiazine drugs were studied by using computational simulation method. Then the two dummy templates were used to synthesize two molecularly imprinted polymers respectively. Results showed that the recognition abilities of the two polymers were consistent with the theoretical calculation. Then a solid phase extraction column was developed for extraction of the four phenothiazines in meat (pork, chicken) followed by determination with high performance liquid chromatography. The column showed high adsorption capacities (850-962ng analyte per milligram of polymer) and high recoveries (93-98%) to the four drugs, and could be recycled for sixty times. The limits of detection were in the range of 1.0-10ng/g, and the recoveries from the fortified blank samples were in the range of 70.3-96.1%. This is the first study reporting the use of molecularly imprinted polymer-based method for determination of phenothiazines residues in foods.

TDDFT studies on electronic structures, chiroptical properties and solvent effect on the CD spectra of diphosphonate-functionalized polyoxomolybdates.

The ultraviolet-visible and electronic circular dichroism (UV-vis/ECD) spectra of diphosphonate-functionalized asymmetric cantilever-type chiral polyoxomolybdate (POM) enantiomer R-{Mo2O5[(Mo2O6)NH3CH2CH2CH2C(O)(PO3)2]2}(6-) (R) were systematically investigated using time-dependent density functional theory (TDDFT) method. From the view of molecular structure and relative energy, we inferred that there is likely a structural conversion from enantiomers R to S-{Mo2O5[(Mo2O6)NH3CH2CH2CH2C(O)(PO3)2]2}(6-) (S) via the intermediate configuration (IN). The ECD spectra of the enantiomer R were produced over the range of 3.0-6.3eV. The UV-vis and ECD spectra of enantiomer R in the gas phase and different solvents were calculated. The results reveal that the UV-vis and ECD spectra of the chiral POM in gas phase, polar solvent, or non-polar solvent are different. The calculated electron density difference maps (EDDMs) display that the POM cluster is a chiroptical chromophore in studied compound.

TDDFT studies on the structures and ECD spectra of chiral bisarylimidos bearing different lengths of o-alkoxy chain-substituted polyoxomolybdates.

The chiroptical properties of bisarylimidos bearing o-alkoxy chain-substituted polyoxomolybdates [Mo(6)O(17)(2,2'-NC(6)H(4)OC(n)H(2n)OC(6)H(4)N)](2-) [n=4(2), 6(3±), 8(4)] were investigated using the time-dependent density functional method. The results showed that the studied chiral polyoxometalates (POMs) manifested similar absorption sites but displayed different shapes and magnitudes in their electronic circular dichroism (ECD) spectra. The ECD spectra of the studied chiral POMs originated from charge-transfer (CT) transitions from arylimido fragments to the POM cages and from oxygen atoms to the molybdenum atoms in the POM cages. The o-alkoxy chain served as a scaffold for generating chirality rather than contributing to the ECD spectrum of the studied POMs. The induced chiralities of the POM cages were defined by the CT transitions, which were completely localized on the POM cages. Furthermore, the long-range corrected CAM-B3LYP hybrid functional and a basis set that is larger than Lanl2DZ should be used for ECD calculations of chiral POMs. Our work establishes the use of computational studies to investigate the chiroptical properties of chiral POMs and provides theoretical interpretations.

Optimization of the coagulation-flocculation process for pulp mill wastewater treatment using a combination of uniform design and response surface methodology.

Pulp mill wastewater was treated using the coagulation-flocculation process with aluminum chloride as the coagulant and a modified natural polymer, starch-g-PAM-g-PDMC [polyacrylamide and poly (2-methacryloyloxyethyl) trimethyl ammonium chloride], as the flocculant. A novel approach with a combination of response surface methodology (RSM) and uniform design (UD) was employed to evaluate the effects and interactions of three main influential factors, coagulant dosage, flocculant dosage and pH, on the treatment efficiency in terms of the supernatant turbidity and lignin removals as well as the water recovery. The optimal conditions obtained from the compromise of the three desirable responses, supernatant turbidity removal, lignin removal and water recovery efficiency, were as follows: coagulant dosage of 871 mg/L, flocculant dosage of 22.3 mg/L and pH 8.35. Confirmation experiments demonstrated that such a combination of the UD and RSM is a powerful and useful approach for optimizing the coagulation-flocculation process for the pulp mill wastewater treatment.

A new and facile method for measurement of apparent density of monodisperse polymer beads.

The apparent density, an intrinsic physical property of polymer beads, plays an important role in the application of beads in micro-total analysis systems and separation. Here we have developed a new, facile and milligram-scale method to describe the motion of beads in aqueous solution and further detect the apparent density of beads. The motion of beads in solutions is determined by the viscosity of solutions and the density difference between beads and solutions. In this study, using various glycerol aqueous solutions with certain viscosities and densities, the motion time (i.e. floating or sedimentation time) of hybrid polymer beads was experimentally measured and theoretically deduced, and consequently, the apparent density of monodisperse beads can be quickly and easily calculated. The results indicated that the present method provided a more precise way to predict the movement of hybrid beads in aqueous solution compared with the approach for commercial use. This new method can be potentially employed in flow cytometry, suspension stability, and particle analysis systems.

[Application of GORE-TEX Dual Mesh fixing into peritoneum in sigmoid-colostomy to prevent peristomal hernia].

OBJECTIVE: To investigate the effect of GORE-TEX Dual Mesh fixing into peritoneum in sigmoid-colostomy on the prevention of peristomal hernia. METHODS: Sixty patients undergone sigmoid-colostomy from Jan. 2003 to Jan. 2005 in the first affiliated hospital of Sun Yat-sen University were selected and randomly divided into two groups. Patients received papillary sigmoid-colostomy through rectus abdominis and peritoneum in control group and GORE-TEX Dual Mesh fixing into peritoneum during sigmoid-colostomy in observation group. Complications and recurrence rate were recorded in follow-up period. RESULTS: Peristomal hernia occurred in eight patients (8/30) in control group (26.7%), while no hernia happened in observation group (0/30). CONCLUSION: GORE-TEX Dual Mesh fixing into peritoneum in sigmoid-colostomy can prevent peristomal hernia.

Prospective study of reconstructing pelvic floor with GORE-TEX Dual Mesh in abdominoperineal resection.

BACKGROUND: Mesh reconstruction has been proved to be an effective method in incisional hernia repairment. This study was designed to evaluate the effect of reconstructing the pelvic floor with the high-inlay expanded polytetrafluoroethylene (ePTFE) GORE-TEX Dual Mesh (WLGore And Associates, Flagstuff, USA) in abdominoperineal resection. METHODS: Sixty patients who underwent abdominoperineal resection for rectal cancer were assigned to 2 groups. The pelvic peritoneum was closed by routine sutures in group 1 and reconstructed with ePTFE in group 2. Postoperative complications and related items were evaluated and the patients were followed up. RESULTS: Time of confining to bed, bowel function recovery, fasting, and detaining drainage were significantly different between two groups (P < 0.05). In group 1, three patients developed bowel obstruction (10%), while no bowel obstruction was observed in group 2. CONCLUSION: Reconstruction of the pelvic floor using ePTFE results in quicker postoperative recovery and could decrease the risk of postoperative intestinal obstruction.