Search

Polyoxyethylene lauryl ether (POELE10)-Na 2 C 4 H 4 O 6 aqueous two-phase extraction system (ATPES) is a novel and green pretreatment technique to trace samples. ATPES coupled with high-performance liquid chromatography (HPLC) is used to analyze synchronously sulfadiazine (SDZ) and sulfamethazine (SMT) in animal by-products (i.e., egg and milk) and environmental water sample. It was found that the extraction efficiency (E%) and the enrichment factor (F) of SDZ and SMT were influenced by the types of salts, the concentration of salt, the concentration of POELE10 and the temperature. The orthogonal experimental design (OED) was adopted in the multi-factor experiment to determine the optimized conditions. The final optimal condition was as following: the concentration of POELE10 is 0.027 g mL −1 , the concentration of Na 2 C 4 H 4 O 6 is 0.180 g mL −1 and the temperature is 35 °C. This POELE10-Na 2 C 4 H 4 O 6 ATPS was applied to separate and enrich SDZ and SMT in real samples (i.e., water, egg and milk) under the optimal conditions, and it was found that the recovery of SDZ and SMT was 96.20–99.52% with RSD of 0.35–3.41%. The limit of detection (LOD) of this method for the SDZ and SMT in spiked samples was 2.52–3.64 pg mL −1 , and the limit of quantitation (LOQ) of this method for the SDZ and SMT in spiked samples was 8.41–12.15 pg mL −1 . [ABSTRACT FROM AUTHOR]

The binodal curves of the aqueous two-phase system (ATPS)containingthe polyoxyethylene (10) lauryl ether (POELE10, C32H66O11) and three potassium salts (KOH/K2CO3/K3PO4) were determined at thetemperatures (288.15, 293.15, 303.15, and 308.15) K. The three experienceequations were used to fit the binodal data for the studied systems,and a satisfactory correlation effect was obtained. The effect ofsalts on the binodal curves for the investigated systems was discussedby the effective excluded volume (EEV), and we found that the salting-outeffect is mainly influenced by valence of anion of salts. The saltcontaining the higher valence of anion has a stronger phase-formingability than that with a lower charge of anion. The liquid–liquidequilibrium (LLE) data for the investigated systems were determinedand correlated by the Othmer–Tobias and Bancroft equations.The effect of the change of temperature on the binodal curves andtie-lines was also studied through the analysis of the EEV valuesand cloud point (CP) figure. The increase in temperature leads tothe strengthening hydrophobicity of POELE10 that drive more watertransferring from the top phase to the bottom phase, which means thephase-forming ability of the whole systems was strengthened. Thus,the critical concentration of POELE10 and salts for forming ATPS decreaseswith the rising temperature. [ABSTRACT FROM AUTHOR]

Polyoxyethylene lauryl ether (POELE10)-NaH 2 PO 4 aqueous two-phase extraction system (ATPES) is coupled with HPLC to analyze chloramphenicol (CAP) in aquatic product. Response surface methodology (RSM) was adopted in the multi-factor experiment to determine the optimized conditions. The extraction efficiency of CAP ( E %) is up to 99.42% under the optimal conditions, namely, the concentration of NaH 2 PO 4 , the concentration of POELE10, pH and temperature were 0.186 g·mL −1 , 0.033 g·mL −1 , 3.8 and 25 °C respectively. The optimal value of enrichment factor of CAP (F) was 22.56 when the concentration of NaH 2 PO 4 was 0.192 g·mL −1 , the concentration of POELE10 was 0.024 g/ml, pH was 4.2 and temperature was 30 °C. The limit of detection (LOD) and limit of quantification (LOQ) of this method are 0.8 μg·kg −1 and 1 μg·kg −1 , which meet the needs of determining trace or ultratrace CAP in food. The E % and F of this technique are much better than other extraction methods. [ABSTRACT FROM AUTHOR]

Thebinodal curves of the aqueous two-phase system (ATPS) containingpolyoxyethylene (10) lauryl ether (POELE10, C32H66O11) and three tartrate salts ((NH4)2C4H4O6, K2C4H4O6, and Na2C4H4O6) were determined at the temperatures (288.15,298.15, and 308.15) K. The binodal data in the studied systems werefit by three known equations, and a satisfactory correlation effectwas obtained. The liquid–liquid equilibrium (LLE) data forthe investigated systems were calculated by computer software in termsof the lever rule and correlated by the Othmer–Tobias and Bancroftequations, respectively. The salting-out ability of salt was discussedfrom two different perspectives: anion and cation. The analysis onthe Gibbs free energy of hydration of the ions and the binodal curvesfound that the salting-out ability of salt strengthened with the increasein absolute value of the Gibbs free energy of anion (cation) whenthe salt consisted of the same cation (or anion). The order of salting-outability of salts with the same cation was KOH < K2C4H4O6< K2CO3< K2HPO4< K3PO4, and the order of salting-out ability of salts with the same anionwas (NH4)2HPO4< K2HPO4and (NH4)2C4H4O6< K2C4H4O6< Na2C4H4O6. The effect of temperature on the phase diagram of ATPS wasstudied. It was found that it is favorable to form the ATPS when thetemperature rises and that the absolute value of the slope of thetie-line (STL) increased with the rising temperature. In the investigatedsystems, the effective excluded volume (EEV) is calculated at thedifferent temperatures, and it was found that the greater value ofEEV of the systems corresponds to the stronger phase formation ofthe ATPS. [ABSTRACT FROM AUTHOR]

Highlights: [•] The phase diagrams of POELE10-organic salts ATPSs were determined experimentally. [•] The experiential equations were used to correlate the binodal data. [•] The effect of salt on the binodal curve for the studied systems has been discussed. [•] The LLE data were correlated using the thermodynamic model. [ABSTRACT FROM AUTHOR]

Abstract: The phase diagrams for the systems containing polyoxyethylene (10) lauryl ether (POELE10) and three salts (KOH, K2CO3 and K3PO4) have been determined experimentally. Three experiential equations were used to correlate the binodal data. The liquid–liquid equilibrium data of these systems were obtained by experimental method and calculated method using lever rule. The tie-line data were correlated by using Othmer-Tobias and Bancroft and simple Setschenow-type equations. Furthermore, the effect of salt on the binodal curve for the studied systems has been discussed by means of salting-out coefficient, effective excluded volume (EEV) and Gibbs free energy of hydration of the ions (ΔG hyd). It was found that the salts composed of anion with a higher valence are better salting-out agents than those with a lower valence. The order of salting-out abilities of salts is K3PO4 > K2CO4 > KOH for the investigated systems. Finally, the phase-separation ability of POELE10 is more powerful compared with that of other polymers and two-phase can easily form at the lower concentration, which indicates that lower cost is a remarkable advantage of POELE10–salt ATPSs. [Copyright &y& Elsevier]