Aqueous Surfactant Two‐Phase Systems for the Continuous Countercurrent Cloud Point Extraction

Aqueous nonionic surfactant solutions split into two phases if the temperature is increased beyond a certain temperature, the so‐called cloud point temperature. Presently many different types of nonionic surfactants are produced commercially, out of these numerous have been considered as potential solvent for the cloud point extraction. In this work the crucial thermophysical properties of nonionic surfactants are investigated to determine the potential of surfactant systems for extraction processes. Phase equilibria of the binary system Triton X‐114/water and the ternary system Triton X‐114/water/phenol were measured. Based on these data the cloud point extraction was implemented in a continuous stirred extraction column. It was found, that increasing temperature within the column reduces the loss of surfactant and leads to an increasing enrichment factor. This work demonstrates that surfactant/water systems represent a suitable alternative to conventional solvents and can effectively be processed in continuous extraction columns.     

Determination of Ni and Zn in an Oil Matrix using Schiff Base‐Assisted Extraction Followed by a Flame Atomic Absorption Spectrometer: A Simple Strategy to Determine Ni and Zn

In the present work, a new and simple Schiff base‐assisted extraction strategy for Ni and Zn from an edible oil matrix with subsequent determination using a flame atomic absorption spectrometer was suggested. According to the green approach, laborious sample‐pretreatment procedures were eliminated via complexation of the analytes with N,N′‐bis(4‐methoxysalycylidene)‐2‐hydroxy‐1,3‐propanediamine (4MSHP) and transferred from the oil phase to the aqueous phase. The complexation properties of 4MSHP, Ni, and Zn were investigated using UV–vis spectrophotometry. The experimental conditions that affect the extraction efficiency were optimized using central composite design. The optimum conditions for the extraction of Ni and Zn were as follows: a volume to oil mass ratio of 0.83 to 1.31 mL g^?1 of 4MSHP solution; 62.3‐ and 50.6‐min, stirring time; 27.3 and 31.1 °C, temperature, respectively. The detection limits (3s_bm^?1) were 0.41 μg g^?1 for Ni and 0.16 μg g^?1 for Zn. Validation of the suggested work was performed by the analysis of organometallic standard‐doped n‐hexane solutions as certified reference materials under the optimum experimental conditions. The recovery percentages were warranted the accuracy and found as 98.2 ± 1.8% for Ni and 99.8 ± 1.2% for Zn. In addition, relative SD values were below 5% for both the analytes. The Student's t‐test showed that there was no significant difference between the found and doped amount of analytes at 95% confidence level. The features such as the detection technique, cheapness, eco‐friendly solvent usage, and practicality were better compared to the literature.     

Rapid and Green Analytical Method for the Determination of Quinoline Alkaloids from Cinchona succirubra Based on Microwave-Integrated Extraction and Leaching (MIEL) Prior to High Performance Liquid Chromatography

Quinas contains several compounds, such as quinoline alkaloids, principally quinine, quinidine, cinchonine and cichonidine. Identified from barks of Cinchona, quinine is still commonly used to treat human malaria. Microwave-Integrated Extraction and Leaching (MIEL) is proposed for the extraction of quinoline alkaloids from bark of Cinchona succirubra. The process is performed in four steps, which ensures complete, rapid and accurate extraction of the samples. Optimal conditions for extraction were obtained using a response surface methodology reached from a central composite design. The MIEL extraction has been compared with a conventional technique soxhlet extraction. The extracts of quinoline alkaloids from C. succirubra obtained by these two different methods were compared by HPLC. The extracts obtained by MIEL in 32 min were quantitatively (yield) and qualitatively (quinine, quinidine, cinchonine, cinchonidine) similar to those obtained by conventional Soxhlet extraction in 3 hours. MIEL is a green technology that serves as a good alternative for the extraction of Cinchona alkaloids.     

Stir Bar Sorptive Extraction: A New Quantitative and Comprehensive Sampling Technique for Determination of Chemical Signal Profiles from Biological Media

Various applications of a novel sampling procedure in chemical ecology are outlined. The stir bar extraction method features the analytical reproducibility needed in recording the analytical profiles of volatile and semivolatile components of biological mixtures. This methodology has been demonstrated here through the examples of small volume urine samples, glandular tissue volatiles, and the air blown through animal cages. Its analytical merits are compared with those of the previously established purge-and-trap (dynamic headspace) technique.