An automated system for preconcentration on imprinted polymer and laser diode spectrometric determination of uranium in mineral water samples

A study, where uranium was online enriched and laser diode spectrometry was determined, was performed with some bottled mineral water samples. A uranium-imprinted polymer (PMDU) was synthesized and characterized for preparation of a specific adsorbent of UO₂²⁺ cations. The homemade system preconcentrated uranium in PMDU resin and determined using an Arsenazo III complex at 650 nm in a combined laser diode spectrometer. All analytical parameters of the system were optimized at 5.5 of the retention pH, 6.0 N HClO₄ of eluent concentration, 0.05% of Arsenazo III complex, and a 40 mm coil length. The effect of interferent ions was also investigated and LOD and LOQ values were found to be 0.54 and 1.80 ng mL^-1 respectively. Sample throughput was 12 h^-1, the preconcentration factor was 50, and RSD% value was 1.1. Certified reference materials of TMDA 52.3 and TMDA 62.2 were quantitatively analyzed and the proposed method was successfully applied to the bottled mineral water samples.

Determination of 3,5 - dimethylpyrazolium glyceroborate nitrification inhibitor in nitrogen fertilizer samples: HPLC-DAD method development and validation for 3,5 - dimethylpyrazole

3,5 - Dimethylpyrazolium glyceroborate is a nitrification inhibitor (a member of pyrazole derivatives) used for the fixation of nitrogen into the soil. In this study, an HPLC-DAD method was developed and validated for determination of 3,5 - dimethylpyrazole in order to determine 3,5 - dimethylpyrazolium glyceroborate in fertilizer samples. For method development, analytical parameters like type of eluent solution and column filling material and device parameters like eluent flow rate, column oven temperature and measurement wavelength were all optimized. For method validation, implementations were performed for linearity, limit of detection (LOD), limit of quantification (LOQ), specificity, stability, intra- and inter-day precision and accuracy. The developed and validated method was used for inhibitor detection in nitrogenous fertilizers. Sample analyses were performed with 95.6-103.3% recovery rates and 0-4.61% relative errors.

DLLME-spectrophotometric determination of glyphosate residue in legumes

A new separation and pre-concentration method for spectrophotometric determination of glyphosate herbicide was developed. Glyphosate was converted into dithiocarbamic acid with CS2, followed by copper in the presence of ammonia to promote complex formation. This complex was collected in a CH2Cl2 organic drop and absorbance measured at 435nm. The analytical parameters, such as the amount of NH3, Cu(II) and CS2, type of extraction solutions, and the ratio of dispersive and organic liquids were optimized. The calibration curve was linear in the range 0.5-10mgl-1. The limits of detection and quantification were calculated from 3s to 10s criterions as 0.21mgl-1 and 0.70mgl-1, respectively. The developed method was applied to legume samples with the satisfactory recovery values of 98±4-102±3%.

Determination of Aluminum in Dialysis Concentrates by Atomic Absorption Spectrometry after Coprecipitation with Lanthanum Phosphate

This method was developed for the determination of trace amounts of aluminum(III) in dialysis concentrates using atomic absorption spectrometry after coprecipitation with lanthanum phosphate. The analytical parameters that influenced the quantitative coprecipitation of analyte including amount of lanthanum, amount of phosfate, pH and duration time were optimized. The % recoveries of the analyte ion were in the range of 95-105 % with limit of detection (3s) of 0.5 µg l^-1. Preconcentration factor was found as 1000 and Relative Standard Deviation (RSD) % value obtained from model solutions was 2.5% for 0.02 mg L^-1. The accuracy of the method was evaluated with standard reference material (CWW-TMD Waste Water). The method was also applied to most concentrated acidic and basic dialysis concentrates with satisfactory results.

The impact of the extent and severity of coronary artery disease on fractional flow reserve measurements

OBJECTIVE

Coronary angiography has a limitation to determine the severity of intermediate stenosis (30-70%)1,2. Fractional flow reserve (FFR) is a method for the assessment of the intermediate stenosis severity3. The effect of coronary artery disease (CAD) severity on the FFR results is not clear. In this study, we aimed to expose the effect of CAD severity calculated with Syntax and Gensini scores on FFR results.

PATIENTS AND METHODS

We scanned patients data (n=378) who had undergone fractional flow reserve measurements in our center. Patients with acute coronary syndrome in the last month, moderate or severe valvular diseases, acute heart failure, serious bradycardia, atrial fibrillation/flutter, severe left ventricular hypertrophy or patient with deficient data were excluded. 351 patients were included in the study. Syntax and Gensini scores were calculated and compared with FFR results. Hemodynamically significant result for FFR, ratio <0.80 was accepted.

RESULTS

The negative correlation between high Gensini, high Syntax scores and FFR results was statistically significant. Especially patients with Syntax scores >22 had notable more crucial lesions in FFR measurements (p<0.001). Cardiovascular disease risk factors such as age, gender, hypertension, diabetes mellitus and dyslipidemia did not correlate with the FFR results. Patients with intermediate stenosis (30-70%) and high Gensini and high Syntax scores were found to have more hemodynamically significant on FFR measurements (FFR <0.80).

CONCLUSIONS

Intermediate lesions with high Syntax score should be evaluated by hemodynamic procedures and treated more carefully with optimal medical treatment or revascularization. Revascularization method of CAD with high Syntax score should be decided with hemodynamic procedures as FFR measurements.