This work investigates the analytical possibilities of high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS) for the determination of Pd, Pt and Rh (PGMs) in ...spent automobile catalysts without chemical separation. A novel approach for the microwave dissolution with the mixture of HCl and H2O2 (4:1) was developed for the further HR CS GFAAS. It was found that within 20 min at the temperature 210 °C of the PGMs quantitatively and simultaneously transferred to solution. It did not show any matrix interferences in determining Pd and Rh, when using HR CS GFAAS for determining the PGMs. When determining Pt, the matrix effect can be expressly minimized by diluting the sample or applying a corrective model. Limits of quantification (μg l−1) by HR CS GFAAS achieved were 1 (Pd), 2 (Pt), and 0.5 (Rh). Correlation coefficients were 0.9973 (Pd), 0.9995 (Pt), and 0.9983 (Rh). The relative standards deviation for PGM determination by the developed procedure was not higher than 5% in the concentration range 0.0005–0.5% weight. Moreover, validation of the developed multielement method demonstrated its robustness. The trueness of experimental results was assured by comparison with the atomic emission spectrometry with inductively coupled plasma method.
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•New precise and sensitive HR CS GFAAS method for PGM determination was studied.•Sufficient method of spent auto-catalysts microwave decomposition was developed.•Background correction is optimal to eliminate matrix effect on Pt determination.•Robustness of new HR CS GFAAS method was confirmed.
Background
Little is known about the achievement of low density lipoprotein cholesterol (LDL-C) targets in patients at cardiovascular risk receiving stable lipid-lowering therapy (LLT) in countries ...outside Western Europe.
Methods
This cross-sectional observational study was conducted in 452 centres (August 2015−August 2016) in 18 countries in Eastern Europe, Asia, Africa, the Middle East and Latin America. Patients (n = 9049) treated for ≥3 months with any LLT and in whom an LDL-C measurement on stable LLT was available within the previous 12 months were included.
Results
The mean±SD age was 60.2 ± 11.7 years, 55.0% of patients were men and the mean ± SD LDL-C value on LLT was 2.6 ± 1.3 mmol/L (101.0 ± 49.2 mg/dL). At enrolment, 97.9% of patients were receiving a statin (25.3% on high intensity treatment). Only 32.1% of the very high risk patients versus 51.9% of the high risk and 55.7% of the moderate risk patients achieved their LDL-C goals. On multivariable analysis, factors independently associated with not achieving LDL-C goals were no (versus lower dose) statin therapy, a higher (versus lower) dose of statin, statin intolerance, overweight and obesity, female sex, neurocognitive disorders, level of cardiovascular risk, LDL-C value unknown at diagnosis, high blood pressure and current smoking. Diabetes was associated with a lower risk of not achieving LDL-C goals.
Conclusions
These observational data suggest that the achievement of LDL-C goals is suboptimal in selected countries outside Western Europe. Efforts are needed to improve the management of patients using combination therapy and/or more intensive LLTs.
The Mendeleev Periodic Table of Chemical Elements delivered a strong impetus to the development of fundamental and applied chemistry, chemical technology, analytical chemistry, and material sciences. ...Each element under the Periodic Table is an idealized substance with a certain structure and properties as defined by existing theoretical frameworks. In the real world, we deal with substances that are close in composition to the element of Periodic Table under study but differ in the presence of different elements in them – impurities that distort (sometimes radically) the structure and properties of the target research object. For many centuries, humanity has sought to obtain pure substances in order to achieve desired properties. In the second half of the 20
century, a unique collection of high purity substances was created, which includes samples representing material artifacts, prototypes of elements of Periodic Table that contain record low contents of impurity elements. With ongoing scientific and technological progress, the achieved purity of substances continuously increases and, therefore, their approximation to idealized elements of Periodic Table. This is facilitated by: new technological processes for the production and storage of high purity substances with a constant decrease in the level of impurities; the creation of isotope-friendly substances; complexes of more highly sensitive multi-element analysis methods; identification of the unique properties of high purity substances, bringing them closer to the capabilities of analog elements of Periodic Table and much more. This article is devoted to progress in these areas. Special attention is also paid to the problems in modern analytical chemistry of high purity substances and the use of the latter in the metrology of chemical analysis as the standards of comparison.
This paper describes the potential of high-resolution continuum source graphite furnace atomic absorption spectrometry for determination of Pt, Pd and Rh after separation and concentration by ...original in-house developed heterochain polymer S, N-containing sorbent. The methods of sample preparation of spent ceramic-based autocatalysts were considered, two of which were used: autoclave decomposition in mixture of acids HCl:HNO3 (3:1) and high-temperature melting with K2S2O7. Both methods anyway limit the direct determination of analytes by HR CS GFAAS. Using the first method it is an incomplete digestion of spent autocatalysts samples, since the precipitate is Si, and the rhodium metal dissolves with difficulty and partially passes into solution. In contrast to the first method, the second method allow to completely transfer analytes into solution, however, the background signal produced by the chemical composition of the flux, overlaps the analytical zone.
It was found, that Pt, Pd and Rh contained in the spent ceramic automotive catalysts could be effectively separated and concentrated by heterochain polymer S, N-containing sorbent, which has high sorption capacity, selectivity and resistant to dilute acids. The chosen HR CS GFAAS analysis conditions enable us to determine Pt, Pd and Rh with good metrological characteristics. The concentrations of Pt, Pd and Rh in two samples of automobile exhaust catalysts were found in range of 0.00015–0.00050; 0.170–0.189; 0.0180–0.0210wt%, respectively. The relative standard deviation obtained by HR CS GFAAS was not more than 5%. Limits of detection by HR CS GFAAS achieved were 6.2·10−6wt% for Pt, 1.8·10−6wt% for Pd, and 3.4·10−6wt% for Rh. Limits of determination achieved by HR CS GFAAS were 1.1·10−5wt% for Pt, 6.9·10−5wt% for Pd, and 8.3·10−5wt% for Rh.
To control the accuracy of PGM in sorption concentrates by HR CS GFAAS method, it was appropriate to conduct an inter-method comparative experiment. The researches on the application of atomic-emission spectroscopy method with inductively coupled plasma as a comparative method were conducted. In addition, the trueness control of the obtained results is confirmed by added-found method.
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•Digestion of spent ceramic-based autocatalysts by two methods: autoclave decomposition in mixture of acids HCl:HNO3 (3:1) and high-temperature melting with K2S2O7.•Use of heterochain polymer S, N-containing sorbent is the optimal way to separate from matrix elements and concentrate Pt, Pd and Rh.•Limits of determination achieved by HR CS GFAAS were 1.1·10−5wt% for Pt, 6.9·10−5wt% for Pd, and 8.3·10−5wt% for Rh.•The combined method for the determination of Pt, Pd and Rh in spent ceramic-based autocatalysts was developed using high resolution electro-thermal atomic absorption spectrometry with a continuum spectrum source (HR CS GFAAS).•The analytes were determined with a relative error less than 5%.
A novel approach is developed for the determination of Co and Au dopants in advanced materials based on tin oxide using high-resolution continuum source graphite furnace atomic absorption ...spectrometry (HR CS GFAAS) with direct slurry sampling. Sodium carboxylmethylcellulose (Na-CMC) is an effective stabilizer for diluted suspensions. Use Na-CMC allows to transfer the analytes into graphite furnace completely and reproducibly. The relative standard deviation obtained by HR CS GFAAS was not higher than 4%. Accuracy was proven by means inductively coupled plasma mass spectrometry (ICP-MS) in solutions after decomposition as a comparative technique. To determine Au and Co in the volume of SnO2, the acid decomposition conditions (HCl, HF) of the samples were suggested by means of an autoclave in a microwave oven.
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•Determination of Au and Co dopants in advanced materials based on SnO2•High-resolution continuum source graphite furnace atomic absorption spectrometry with the direct slurry sampling•Use of sodium carboxylmethylcellulose as is an effective stabilizer of the suspensions•ICP-MS analysis of the solutions after the decomposition of the advanced materials
Objective:
In primary hypercholesterolemia many people treated with statins do not reach their plasma LDL-C goals and are at increased risk of cardiovascular disease (CVD). This study aimed to ...evaluate efficacy and safety of a new fixed-dose combination (FDC) formulation of rosuvastatin/ezetimibe (R/E) in this population.
Methods:
This was a multicenter, multinational, randomized, double-blind, double-dummy, active-controlled, parallel-arm study of FDC R/E in people with primary hypercholesterolemia at very high risk (VHR) or high risk (HR) of CVD, inadequately controlled with 20 mg or 10 mg stable daily dose of rosuvastatin or equipotent dose of another statin. The primary objective was to demonstrate superiority of FDC R/E versus rosuvastatin monotherapy uptitrated to 40 mg (R40) or 20 mg (R20) in reduction of LDL-C after 6 weeks.
Results:
Randomized VHR participants (n = 244) were treated with R40, R40/E10, or R20/E10; randomized HR participants (n = 208) received R10/E10 or R20. In VHR participants, superiority of R40/E10 and R20/E10 versus R40 was demonstrated on LDL-C percent change from baseline to Week 6 with least squares mean differences (LSMD) of −19.66% (95% CI: −29.48% to −9.84%; P < .001) and −12.28% (95% CI: −22.12% to −2.44%; P = .015), respectively. In HR participants, superiority of R10/E10 over R20 was not demonstrated (LSMD −5.20%; 95% CI: −15.18% to 4.78%; P = .306), despite clinically relevant LDL-C reduction with R10/E10. No unexpected safety findings were reported.
Conclusions:
The results from this study suggest that R/E FDCs improve LDL-C reduction and goal achievement in people with primary hypercholesterolemia inadequately controlled with statins and at VHR/HR of CVD.
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