Determination of toxic heavy metals in fish samples using dispersive micro solid phase extraction combined with inductively coupled plasma optical emission spectroscopy.

Monitoring of toxic heavy metals in fish samples is a matter of a great importance from the nutritional and toxicological points of view. A dispersive micro solid phase extraction (dµSPE) for preconcentration of trace Pb, Cd, Hg, Co, Ni ions using pectin coated magnetic graphene oxide (pectin/Fe3O4/GO) is presented. Inductively coupled plasma optical emission spectroscopy (ICP/OES) was utilized for analyzing the samples. The influence of parameters name as pH, extraction time, sample volume and amount of sorbent were optimized using central composite design (CCD) methodology. Detection and quantification limits were between 0.01 and 0.21 µg g-1 and 0.04-0.67 µg g-1 of fresh fish sample, respectively. Accuracy of the method verified using certified reference materials (NIST-SRM-1946). Concentration of the toxic heavy metals were successfully determined in 11 different fish samples using the proposed method.

Tympanosclerosis and atherosclerosis plaques: a comparative analytical study on some new microbiological and immunohistochemical aspects.

PURPOSE: The aim of this study was to compare chemical contents, expression of BMP-8a, and the presence of Mycoplasma and ExoS-ExoU exotoxins producing Pseudomonas aeruginosa in tympanosclerosis (TS) and atherosclerosis (AS) plaques. METHODS: Thirty-six cases with TS and AS plaques (18 each) were selected and examined for chemical, immunohistochemical, and microbial analysis. SPSS ver. 21 and t test analysis were used for comparing the findings, and the level of significance was considered as p < 0.05. RESULTS: TS plaques showed lower carbon, higher calcium, and phosphorous contents compared to AS plaques (p value < 0.05). Chlorine was detected in AS plaques (1.8 w%) which could probably be due to the presence of myeloperoxidase (MPO) in atherosclerotic artery. Contrary to spherical shape of the surface of TS plaques, AS plaques were needle shaped. BMP-8a expression in TS plaques (59.5%) was significantly higher (p value < 0.0001) than AS plaques (20%). Of the 18 TS specimens, 12, 14, and 3 were positive for ExoS, ExoU Pseudomonas aeruginosa, and Mycoplasma genes, respectively, while of the 18 AS specimens, 2, 2, and 3 were positive for ExoS, ExoU Pseudomonas aeruginosa, and Mycoplasma genes, respectively. CONCLUSION: TS plaques are different from AS plaques in terms of elemental components, surface morphology, and BMP-8a expression. Therefore, different calcification process and pathogenesis may be responsible for these two diseases. The results of our study showed that both TS and AS plaques have genetic footprint of Mycoplasma, but the level of calcium concentration-dependent exotoxins genes was found only in TS plaques.

Determination of toxic heavy metals in rice samples using ultrasound assisted emulsification microextraction combined with inductively coupled plasma optical emission spectroscopy.

A straightforward and efficient method was developed by ultrasound assisted emulsification microextraction (USAEME) combined with inductively coupled plasma optical emission spectroscopy (ICP/OES) to trace some toxic heavy metal ions in eight select farmed and four select imported rice samples. In this study, carbon tetrachloride (CCl4) and 1-(2-pyridylazo)2-naphthol (PAN) were used as the extraction solvent and complexing reagent, respectively. The extraction parameters were optimized by means of a central composite design (CCD). Detection and quantification limits were set to be between 0.02 and 0.08 µg L-1 and 0.07-0.30 µg L-1, respectively. The accuracy of our method was further verified against two certified reference materials namely NCS ZC73029 and NIES No 10-b. While no trace of contaminations was found in some rice samples (Tarom, Hashemi, Sadri, Khazar and one imported sample), others such as Kazemi, Jamshidi, Dom Siah, Guilanehand and three of the imported samples were considerably polluted.

Design, development and evaluation of microRNA-199a-5p detecting electrochemical nanobiosensor with diagnostic application in Triple Negative Breast Cancer.

The new sensitive diagnostic method, electrochemical nanobiosensor, is applied to cancer detection by using specific biomarkers such as miRNA. Studies have shown that for the diagnosis of Triple Negative Breast Cancer (TNBC) patients, in the early stages of the disease, miR-199a-5p as circulating miRNA can be a suitable candidate. In this study, a new electrochemical nanobiosensor for serum miR-199a-5p detection was designed by using modified glassy carbon electrode (GCE) with graphene oxide (GO) and gold nanoroad (GNR) on which a thiolated probe was immobilized. The electrochemical impedance method (EIS) was used to examine the electrochemical characteristics and behavior of nanobiosensor and for verifying the nanomaterial synthesis the scanning electron microscope (SEM) were applied, field emission scanning electron microscope (FE-SEM), UV-Vis spectrophotometry and energy dispersive spectroscopy (EDS). Optimum conditions were investigated for designed nanobiosensor and in optimal conditions, following results were obtained; the linear range of the calibration curve from 15 fM to 148 pM, the detection limit of 4.5 fM, and the standard deviation of 2.9%. The research data showed that our designed electrochemical nanobiosensor has a sensitivity and desirable precision for evaluation of miR-199a-5p that can be used to measure low concentrations of miR-199a-5p in blood serum sample.

Ionic liquid-based dispersive liquid-liquid microextraction for the determination of formaldehyde in wastewaters and detergents.

Spectrophotometry in combination with ionic liquid-based dispersive liquid-liquid microextraction (DLLME) was applied for the extraction and determination of formaldehyde in real samples. The method is based on the reaction of formaldehyde with methyl acetoacetate in the presence of ammonia. The variation in the absorbance of the reaction product was measured at 375 nm. An appropriate mixture of ethanol (disperser solvent) and ionic liquid, 1-hexyl-3-methylimidazoliumhexafluoro-phosphate [C(6)MIM][PF(6)] (extraction solvent) was rapidly injected into a water sample containing formaldehyde. After extraction, sedimented phase was analyzed by spectrophotometry. Under the optimum conditions, the calibration graph was linear in the range of 0.1-20 ng mL(-1) with the detection limit of 0.02 ng mL(-1) and limit of quantification of 0.08 ng mL(-1) for formaldehyde. The relative standard deviation (RSD%, n = 5) for the extraction and determination of 0.8 ng mL(-1) of formaldehyde in the aqueous samples was 2.5%. The results showed that DLLME is a very simple, rapid, sensitive, and efficient analytical method for the determination of trace amounts of formaldehyde in wastewaters and detergents, and suitable results were obtained.