Analytical Methods in Environmental Chemistry Journal
Volume:3 Issue: 3, Sep 2020

In-vitro speciation of inorganic selenium (SeIV and SeVI) in serum blood and urine of hyperthyroidism and hypothyroidism patients based on isopropyl 2-[(isopropoxycarbothiolyl) disulfanyl] ethane thioate (IICDET) as a complexing agent were studied by ultrasound-assisted dispersive liquid-liquid bio-microextraction procedure (USA-DLLMBE). In first stage, 100 μL (≈0.1 g) of hydrophobic ionic liquid of [C8MIM][PF6] mixed with IICDET ligand and 100 μL of acetone. Then, the mixture injected to 10 mL of human samples at pH=4. After shacking, the Se (IV) ions were complexed by IICDET and extracted to IL at pH=4 (R-S: ...Se). The IL phase was separated from sample by centrifuging and inorganic selenium (Se IV) in remained samples was determined by electro thermal atomic absorption spectrometry (ET-AAS) after back extraction of Se (IV). As speciation, the Se (VI) reduced to Se (IV) in acidic pH (HCl, 130OC) and the total Se(T-Se) was obtained at pH=4. Therefore, the Se (VI) was calculated by difference of T-Se and Se (IV). After optimized conditions, the enrichment factor (EF), Linear range and limit of detection (LOD) for inorganic Se (IV) were obtained 20.1, 0.75- 20 μg L-1 and 0.18 μg L-1 in serum and urine samples respectively. The results showed us, the concentration of selenium was decreased in thyroid patients as compared to healthy peoples. The validation of methodology was achieved by certified reference material (CRM) and ICP-MS.

Dispersive liquid–liquid microextraction coupled with UV–Vis spectrophotometry was applied for the determination of zirconium in aqueous samples. In this method a small amount of chloroform as the extraction solvent was dissolved in pure ethanol as the disperser solvent, then the binary solution was rapidly injected by a syringe into the water sample solution containing Zr(IV), xylenol orange and cetyltrimethylammonium bromide (CTAB). The formed ion-associate was extracted into the fine chloroform droplets. The detection limit for Zr(IV) was 0.010 μg mL−1. The precision of the method, evaluated as the relative standard deviation obtained by analyzing of 10 replicates, was 2.7 %. The practical applicability of the developed method was examined using natural waters and ceramic samples.

In this study, feasibility of magnetic bentonite nanocomposite for removal of amoxicillin from wastewater samples was evaluated by high performance liquid chromatography (HPLC). Magnetic bentonite synthesized by co-precipitation of bentonite and Fe3O4 and used for removal of amoxicillin from water samples. Response surface methodology on central composition design (CCD) was applied for designing of experiment and building of model. Three factors including pH, adsorbent dose and temperature were studied and used for quadratic equation model to prediction of optimal points. By solving the equation and considering regression coefficient (R2 =0.98). The optimal points of main parameters were obtained as a pH of 4.68, the adsorbent dosage of 1.50 g and the temperature of 48.90 C. Results showed that three factor are significant on removal efficiency and experimental data are in good agreement with predicted data. Proposed methods were used to analysis of amoxicillin in three real samples

In this work the effect of amoxicillin on copper and zinc (Cu and Zn) deficiency was evaluated by determining of Cu and Zn concentration in human serum and urine samples. By dispersive ionic liquid cloud point extraction procedure (DIL-CPE), 0.03 g of pure amoxicillin drug was added to mixture of 0.1 g of hydrophobic ionic liquid and 0.2 mL acetone which was injected to 2 mL of serum or urine samples which was diluted with DW up to 10 mL. The cloudy solution was shacked for 7 min and Cu and Zn ions was extracted based on sulfur group on amoxicillin ligand at pH of 7 by DIL-CPE. Then, the solution centrifuged and after back extraction with I mL of nitric acid (0.2 M), the remained solution was determined by flame atomic absorption spectrometry (F-AAS). The enrichment factor (EF), LOD and linear range (LR) for copper and zinc was obtained (9.92; 9.81), (28.5 μg L−1; 15.2 μg L−1) and (100 -505 μg L−1; 41- 153 μg L−1), respectively. The results showed us, the concentration of the Cu and Zn ions can be decreased by increasing amoxicillin drug dosage in human body. The mean value for serum copper/zinc ratio was obtained 1.11 ± 0.28. The DIL-LME method was validated by ICP-MS analysis and spike of real samples for Zn and Cu ions in serum and urine samples.

Antibiotics and pharmaceutical products cannot remove by conventional sewage treatment. In this work, an effective adsorbent magnetic multiwalled carbon nanotube (Fe3O4@MWCNTs; MMWCNTs) was synthesized by co-precipitation of MWCNTs with Fe3O4 and used for removal of Metronidazole from aqueous solutions. Response surface methodology on central composition design (CCD) was applied for designing of experiments and building of models for Metronidazole removal before determination by HPLC. Four factors including pH, the adsorbent dose, time, and temperature were studied and used for the quadratic equation model to the prediction of optimal points. By solvent the equation and considering the regression coefficient (R2 =0.9997), the optimal points obtained as follows: pH =2.98; adsorbent dosage =2.16 g; time =22 min and temperature = 37.9 oC. The isotherm study of adsorption showed that the metronidazole adsorption on Fe3O4@MWCNTs follows the Langmuir model. The maximum adsorption capacity (AC) is 215 mg g-1 obtained from Langmuir isotherm. The results showed that three factors including pH, amount of adsorbent, and temperature are significant on removal efficiency and an experimental point was found to agree satisfactorily with the predicted values. The proposed methods coupled to HPLC were used to analysis of metronidazole in six real samples. The results showed the best removal efficiency was obtained at optimal points. Moreover, the reusability of adsorbent showed that the Fe3O4@MWCNTs can be efficiently removed the Metronidazole from aqueous solutions as compared to other

Molybdenum (Mo) ions enter to human body from the diet or drinking waters and have a potentially toxic effect on human. The thiol-functionalized mesoporous silica nanoparticles (HS-MSNPs) was used for determination and speciation of Mo (II, VI) in human biological samples by dispersive ionic liquid-micro-solid phase extraction (DIL-μ-SPE) coupled to electrothermal atomic absorption spectrometry (ET-AAS). Firstly, the mixture of HS-MSNPs (15 mg), the hydrophobic ionic liquid (1-Hexyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate; [HMIM][T(PFE)PF3]) and acetone injected to 10 mL of human blood and serum samples. After shaking for 5 min, the Mo(II) and Mo(VI) ions were extracted with thiol group of MSNPs at pH 6 and 2, respectively and collected through IL in bottom of conical tube by centrifuging. Then, the Mo(II,VI) ions were back-extracted from HS-MSNPs with elent based on changing pH, and remained solutions were determined by ET-AAS after dilution with DW up to 0.5 mL, separately. So, the total of Mo(T-Mo) was simply calculated by the summation of Mo(II) and Mo(VI) content. In optimized conditions, the linear range (LR), the limit of detection and enrichment factor (EF) for Mo(II) and Mo(VI) were obtained (0.41-3.82 μg L−1; 0.48–4.55 μg L−1), (0.1 μg L−1; 0.12μg L−1) and (19.6; 16.5) for 10 mL of human blood samples, respectively (Mean of RSD%=3.3). At optimized pH, the adsorption capacities of the HS-MSNPs for Mo(II) and Mo(VI) was obtained 68.7 mg g-1 and 55.8 mg g-1, respectively. In purposed study, a new analytical method for rapid speciation and determination of trace amount of Mo (II, VI) was used in human blood and serum samples. The developed method was successfully validated by ICP-MS analysis.

A novel method based on the synthesis of dithioglycerol immobilized on carbon nanotubes (CNTs@DTG) was used for speciation of chromium (Cr III and Cr VI) in human blood samples by dispersive micro solid-phase bioextraction (D-μ-SPBE). By procedure, a mixture containing acetone and 1-octyl-3-methylimidazolium hexafluorophosphate ([OMIM][PF6]) and CNTs@DTG were injected into 5 mL of standard and blood sample containing 1.0 μg L-1 of Cr III and Cr VI which was diluted with DW up to 10 mL at optimized pH. The Cr (VI) anions and Cr (III) cations were efficiently extracted by HS of CNTs@DTG at pH 2 and 6, respectively (HS.....Cr) and trapped into IL phase at the bottom of the conical tube. Then, Cr (III) and Cr(VI) ions were back-extracted from the IL/ CNTs@DTG to the aqueous phase by changing pH for each of them before determined by electrothermal atomic absorption spectrometry (ETAAS). Total chromium was calculated by summarizing Cr III and Cr VI content. The enrichment factor (EF), linear range and limit of detection (LOD) were obtained 9.85, 0.12-3.88 μg L-1 and 30 ng L-1, respectively. Validation of the methodology was confirmed with standard addition to real samples and ICP-Ms analysis