Elham Ghasemi

Bio: Elham Ghasemi is an academic researcher from University of Sistan and Baluchestan. The author has contributed to research in topics: Extraction (chemistry) & Spectrophotometry. The author has an hindex of 7, co-authored 11 publications receiving 207 citations.

Room temperature ionic liquid-based dispersive liquid–liquid microextraction of uranium in water samples before spectrophotometric determination

Abstract: A fast, simple and reliable method was developed for the determination of uranium(VI) in water samples based on room temperature ionic liquid dispersive liquid–liquid microextraction (RTIL-DLLME) followed by spectrophotometric determination. This is the first report on the extraction of U6+ by an RTIL-DLLME method. In this method, uranyl ion was complexed with 4-(2-pyridylazo) resorcinol (PAR) in the presence of cetylpyridinium chloride (CPC), which improved complex extraction into ionic liquid. Room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) and methanol were used as extracting and disperser solvents. The factors influencing the extraction efficiency, such as type and volume of RTIL and disperse solvent, extraction time, pH and concentration of the chelating agent and surfactant, and ionic strength were investigated and optimized. The developed protocol was found to yield a linear calibration curve in the concentration range between 50 and 700 μg L−1 with a limit of detection of 2.4 μg L−1. An enrichment factor of 448 fold was observed for the analyte. The repeatability of the method was satisfactory (RSD = 1.6%) and the total analysis time including microextraction was less than 10 min. The method has been successfully applied for the analysis of uranium in three spiked tap, lake and treated wastewater samples.

Determination of Zinc, Copper, and Mercury in Water Samples by Using Novel Micro Cloud Point Extraction and UV-Vis Spectrophotometry

Abstract: A novel micro cloud point extraction (MCPE) was developed as a fast, simple, and economical preconcentration method for spectrophotometric determination of Zn, Cu, and Hg in water samples. In contrary to traditional cloud point extraction, this method does not need heating. To achieve the cloud point in room temperature, the MCPE procedure was carried out in brine. Triton X-114 was employed as a non-ionic surfactant and the analytes were chelated by 4-(2-pyridylazo) resorcinol prior to extraction. The important factors influencing the extraction efficiency were investigated and optimized. Under the optimized condition, calibration curve was found to be linear in the concentration range of 0.15-0.60, 0.02-0.10, and 0.30-0.80 mg.L for Zn, Cu, and Hg respectively with a limit of detection of 51.7, 9.8, and 13.1 μg.L.

Developing a new micro cloud point extraction method for simultaneous preconcentration and spectrophotometric determination of uranium and vanadium in brine.

Abstract: A fast, simple, and economical method was developed for simultaneous spectrophotometric determination of uranium(VI) and vanadium(V) in water samples based on micro cloud point extraction (MCPE) at room temperature. This is the first report on the simultaneous extraction and determination of U(VI) and V(V). In this method, Triton X114 was employed as a non-ionic surfactant for the cloud point procedure and 4-(2-pyridylazo) resorcinol (PAR) was used as the chelating agent for both analytes. To reach the cloud point at room temperature, the MCPE procedure was carried out in brine. The factors influencing the extraction efficiency were investigated and optimized. Under the optimized condition, the linear calibration curve was found to be in the concentration range between 100 - 750 and 50 - 600 μg L(-1) for U(VI) and V(V), respectively, with a limit of detection of 17.03 μg L(-1) (U) and 5.51 μg L(-1) (V). Total analysis time including microextraction was less than 5 min.

Recent advances on toxicity and determination methods of mycotoxins in foodstuffs

Abstract: Background Mycotoxins exposure from foodstuffs can trigger serious health hazards (e.g. cancers, deformity and mutation), which has been a global public health concern. In recent years, large-scale poisoning incidents and international trade disputes caused by fungal contamination are extremely common. Unremitting efforts have been devoted to the investigations on classification, toxicity and occurrence of mycotoxins. Monitoring mycotoxins is highly important to ensure human health. Pretreatment technologies offer a pre-analytical separation process for reducing the instruments contamination, signal interference and matrix effects of complex foodstuffs. Scope and approach In this review, the classification, toxicity and occurrence of mycotoxins were concisely summarized. We then concentrated our attentions on the methods of extraction, clean-up, separation and determination of mycotoxins. Especially, the rapid development of nanotechnology has brought many opportunities for sample pretreatment. We have also summarized the available and advanced adsorbents based on the emerging nanomaterials for pretreatment of mycotoxins in foodstuffs. At the end of the article, future opportunities and challenges in the field of mycotoxins research are tentatively proposed. Key Findings and Conclusions: This review comprehensively summarized the latest achievements and improvements in the classification, toxicity, occurrence and detection approaches of mycotoxins. Impressively, the sample pretreatment and detection methods applied for mycotoxins determination in foodstuffs have been summarized, regarding the novel nanomaterial-based pretreatment technologies as well as the development of chromatographic and sensing technologies in the last six years. Furthermore, the current trends and the future perspectives in the toxicity and detection method of mycotoxins are tentatively proposed.

Nanomaterial based electrochemical sensors for the safety and quality control of food and beverages

Abstract: The issue of foodborne related illnesses due to additives and contaminants poses a significant challenge to food processing industries. The efficient, economical and rapid analysis of food additives and contaminants is therefore necessary in order to minimize the risk of public health issues. Electrochemistry offers facile and robust analytical methods, which are desirable for food safety and quality assessment over conventional analytical techniques. The development of a wide array of nanomaterials has paved the way for their applicability in the design of high-performance electrochemical sensing devices for medical diagnostics and environment and food safety. The design of nanomaterial based electrochemical sensors has garnered enormous attention due to their high sensitivity and selectivity, real-time monitoring and ease of use. This review article focuses predominantly on the synthesis and applications of different nanomaterials for the electrochemical determination of some common additives and contaminants, including hydrazine (N2H4), malachite green (MG), bisphenol A (BPA), ascorbic acid (AA), caffeine, caffeic acid (CA), sulfite (SO32−) and nitrite (NO2−), which are widely found in food and beverages. Important aspects, such as the design, fabrication and characterization of graphene-based materials, gold nanoparticles, mono- and bimetallic nanoparticles and metal nanocomposites, sensitivity and selectivity for electrochemical sensor development are addressed. High-performance nanomaterial based electrochemical sensors have and will continue to have myriad prospects in the research and development of advanced analytical devices for the safety and quality control of food and beverages.