Iranian Journal of Analytical Chemistry
Volume:6 Issue: 2, Summer and Autumn 2019

Ionic liquid based ultrasound-assisted dispersive liquid–liquid microextraction of trace levels of Rh3+ ions from aqueous samples is illustrated, to investigate a rapid and reliable sample pretreatment to determine Rh3+ ions spectrophotometrically. The Rh3+ is converted into its complex with 5-(4`-chlorophenylazo)-6-hydroxy-pyrimidine-2,4-dione (CPAHPD) as a complexing agent, and an ultrasonic bath is used with the ionic liquid, 1-octyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl) imide at room temperature is applied to extract the analyte. The centrifuged rhodium complex is enhanced in the form of ionic liquid droplets and prior to its spectrophotometric analysis, 250 µL ethanol is added to the ionic liquid-rich phase. Finally, the influence of various parameters on the recovery of Rh3+ is examined and optimized. Under optimum conditions, the calibration graph is linear in the range of 10–260 ng mL−1, the detection limit is 3.2 ng mL−1 (3Sb/m, n=7) and the relative standard deviation is ± 1.78 % (n=7, C = 150 ng mL−1). Comparison with other procedures, the proposed procedure reduces the danger of exposure to toxic solvents, applied for extraction in conventional extraction procedures, it also requires a shorter extraction time. The method is successfully validated by the analysis of real samples and compared statistically with FG-AAS method. The proposed method is successfully validated by the analysis different complex materials such as environmental  water and alloy samples and compared statistically with ETAAS method.

This paper describes trace determination of malachite green (MG) as a water pollutant dye by convenient spectrophotometry. A water-soluble hyper-branched polyamine was first prepared using the nuclophilic ring opening reaction of diepoxy and diamine monomer, which was then used for functionalization of multiwalled carbon nanotubes. This compound (named WHPA-OMCNT) was applied as a highly efficient adsorbent for the extraction of MG from seawater samples of Chabahar Bay (located in the southern east of Iran). WHPA-OMCNT was used in a pipette-tip solid phase extraction process; and for this extraction, different parameters affecting the extraction efficiency, including type and volume of eluent solvent, sample of volume, number of cycles of extraction and elution, pH of sample solution, type and amount of salt, and concentration of surfactant (triton X-114) were optimized using both one-variable-at-a-time and Box-Behnken response surface methodology techniques employing seven factors in three-levels. Under optimum conditions, the linear range of proposed method for MG was 4-250 µg L-1 with a detection limit of 0.80 µg L-1 and RSDs better than 6.4%.

Simultaneous spectrophotometric determination of some polycyclic aromatic hydrocarbons (PAHs) in wastewater samples after preconcentration by salting-out assisted liquid-liquid extraction was achieved using a doolittle multivariate calibration algorithm (DMCA). The DMCA was applied by lower and upper (LU) triangular matrix decomposition which is efficient, powerful and easily. Results were shown that DMCA has advantages such as, simplicity, rapidness, avoiding matrix inverting and reducing the orders of matrices. The influence of various parameters, such as extraction solvent and volume, type and amount of salt, vortex time and sample pH were studied and optimized. The net analyte signal (NAS) method was used for calculating figures of merit. Linear range (LR) of calibration graphs for naphthalene, anthracene and pyrene were between 0.20 - 2.00, 0.10 - 1.50 and 0.07 -1.00 µg mL-1, respectively. The root mean square errors of prediction (RMSEP) for naphthalene, anthracene and pyrene using DMCA model were 0.0367, 0.0331 and 0.0305, respectively.

In this paper, a simple, sensitive and economical method is described for the extraction and determination of sesame oil oxidation by dynamic headspace extraction combined to ion mobility spectrometry (IMS). Hexanal as a reaction product of oxidation, is used to follow the progress of oil oxidation. The optimization of different variables for the extraction step including: extraction temperature, extraction time and flow rate of carrier gas and also for the determination step by IMS including: drift and corona voltages, flow rate of carrier and drift gases, cell and injection temperatures, and pulse width were performed. Under optimum conditions, the calibration curve was linear in the range of 0.10 to 0.50 ng g-1 and also the relative standard deviation was 3.0%. The detection and quantification limits were 0.03 and 0.12 ng g-1, respectively. The recovery results for spiked samples (90.0-104.0%) demonstrated the potential of the proposed method for determining of oxidation in sesame oil samples.

Generally, traditional bioanalytical methods including in vitro or ex vivo are associated with the limitations and drawbacks in the living systems analysis. However, the in vivo sampling technique is an excellent procedure to improve accuracy and performing the on–line and in–situ biological analyses. In this regard, solid–phase microextraction (SPME) as a simple, sensitive, solventless and noninvasive sample preparation technique has been considered by researchers in in vivo sampling, in recent years. This review briefly describes the use of in vivo SPME as a sample preparation method to study the living systems involving plants and animals (especially metabolomics and clinical researches). Also, biocompatible coatings and design innovations that use to enhance the sensitivity and functioning of the method have been investigated. Finally, the challenges facing the development in vivo SPME method are investigated and forthcoming trends for the better performance of bioanalytical method are offered.

A simple, new and low-cost design of Li-air battery was introduced. An effective synthesized nanocatalyst for modifiying of air cathode, filter paper as a simple separator and a conductive ionic liquid namely 1-Octyl-3-methyl imidazolium hexafluorophosphate abbreviated [Omim][PF6] as a non-aqueous and green electrolyte in battery were used. The MnFe2O4 nanoparticles (NP-MnFe2O4) which consistingof transition metal-metal oxide components was synthesized in our labrature. High discharge capacity, non-flammability of electrolyte, high reversibility, long lifetime and low over potential were observed in electrochemical tests of the battery. Synthesized nanocatalyst was characterized using XRD, FTIR and SEM techniques. XRD results show that a nanocatalyst have a particle sizes of 16-28 nm that distributed on cathode uniformly and performance of battery was improved to more than 1000 cycles compared to battery without any catalyst. The discharge capacity at current density of 0.2 mA cm-2 and charge potential range of 2.0-4.2 V for battery with catalyst/green electrolyte and without catalyst/common organic electrolyte were 3391 and 1012 mAh g-1,respectively. Furthermore, the usage of an ionic liquid as electrolyte leads to the increase the safety and lifetime of battery. Because of used electrolyte have high boiling point amount (>350 Celcius), so if it released to the environment due to the destruction or life expires of battery, don’t seriously damage to the environment because it is not easily evaporated.