Extraction Et Caractérisation Physico-Chimique D’un Sel Végétal À Partir De La Cendre Du Palmier À Huile Du Nord Du Togo

Ce présent travail a porté sur l’extraction et la caractérisation physico-chimique d’un sel végétal fabriqué à base du palmier à huile. L’incinération des branches de palmier à huile donne une cendre qui, par lavage et évaporation donne du sel de palme. L’analyse de la solution obtenue après lavage de cette cendre à l’eau distillée par photométrie à flamme, spectrométrie à absorption atomique et par volumétrie révèle la présence de sodium (84,500 mg/L), potassium (1120 mg/L), calcium (44 mg/L) et magnésium (0,022 mg/L). Ce résultat indique que cette solution est très riche en potassium qu’en sodium et calcium ; le magnésium est présent sous forme de trace. En outre, l’analyse de la cendre obtenue à base de la rafle a révélé que les teneurs en potassium (3331,410 mg/L) et en sodium (497 mg/L) de la rafle sont plus élevées que celles de la branche du palmier à huile. Cependant, le dosage des anions dans une solution obtenue par dissolution de 10 grammes de sel de palme dans un litre d’eau distillée révèle la présence de chlorures (3153,460 mg/L), des hydroxydes (0,289 mg/L), des carbonates (0,180 mg/L) et des hydrogénocarbonates (12,017mg/L). Les concentrations de ces anions indiquent que cette solution est très riche en chlorure qu’aux autres anions trouvés. Par conséquent, le sel de palme est un mélange de sels riche en chlorure de potassium. La quantité de sel végétal obtenue à la préparation contrôlée rapportée à la biomasse végétale est de l’ordre de 1,24% donc assez faible. This paper focuses on the extraction and physic-chemical characterization of plant salt produced from oil palm. The incineration of the oil palm frond gives ash which, by washing and evaporation, gives plant salt. The analysis of the solution obtained after washing the ash by flame photometer, atomic absorption spectrometer and by volumetric reveals the presence of sodium (84.500 mg / L), potassium (1120 mg / L), calcium mg / L) and magnesium (0.022 mg / L). These results show that this solution is very rich in potassium more than sodium and calcium; the magnesium is revealed only in trace. In addition, the analysis on the Empty Fruit Bunche’s ash reveals that it contains more potassium (3331.410 mg/L) and sodium (497 mg/L) than the frond. However, the dosage of a solution obtained by dissolving 10 grams of palm salt in one liter of water also reveals the presence of chloride (3153.460 mg / L), hydroxides (0.289 mg / L), carbonate (0.180 mg / L) and hydrogen carbonate (12.017 mg / L). The concentration of these anions shows that this solution is richer in chloride than the other anions found. Therefore, palm salt is a mixture of salt rich in potassium chloride. The output of the preparation controlled is lower (1.24%) in comparison with the vegetable biomass.

Colorimetric Phosphate Detection Using Organic DFB Laser-Based Absorption Spectroscopy

A novel compact laser absorption spectrometer is developed for colorimetric detection. We demonstrate the realization of the system as well as example measurements of phosphate in water samples based on the malachite green (MG) method. A phosphate concentration range of to (which corresponds to a molar concentration range of to ) is investigated. This photometer demonstrates the ease of integration of organic distributed feedback (DFB) lasers and their miniaturizability, leading the way toward optofluidic on-chip absorption spectrometers. We constructed an optically pumped organic second-order DFB laser on a transparent substrate, including a transparent encapsulation layer, to have access to both emission directions of the surface-emitting laser. Using the two different surface emission directions of the laser resonator allows monitoring of the emitted light intensity without using additional optical elements. Based on these advances, it is possible to miniaturize the measurement setup of a laser absorption spectrometer and to measure analytes, such as phosphate.

Optimization of operating modes of the weak absorption spectrometer

The possibilities of improving the characteristics of a weak absorption spectrometer consisting of a frequency-tunable laser and an external analytical resonator with the test substance are analyzed. The influence of the scanning speed of the laser frequency on the choice of the spectrometer operating modes that provide the required resolution and the required sensitivity of spectral measurements is considered. Particular attention is paid to assessing the role of the interaction of modes in an analytical cavity on the structure of the recorded spectra. It was found that at a high rate of change in the laser frequency and superposition of fields of longitudinal modes, an improvement in the resolving power is combined with a certain decrease in the sensitivity and accuracy of recording weak spectral lines. It is shown that the optimization of the spectrometer operation modes requires correct accounting of the Q-factor of the analytical resonator and the line width of the probe radiation.

New measurement of the β-spectrum of 210Bi with a silicon 4πβ-spectrometer

The shape of 210Bi β-spectrum was measured using a spectrometer based on Si(Li) detectors with a 4π geometry. Full absorption spectrometer allows for a direct measurement of the β-spectra without using the electron backscattering corrections for the response function. The measured value of nuclear shape factor C(W)=1+(-0.4378±0.0072)W+ (0.0526±0.0021) W2 is in agreement with the results of previous studies.

Airborne Mid-Infrared Cavity enhanced Absorption spectrometer (AMICA)

We describe the Airborne Mid-Infrared Cavity enhanced Absorption spectrometer (AMICA) designed to measure trace gases in situ on research aircraft using Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS). AMICA contains two largely independent and exchangeable OA-ICOS arrangements, allowing for the simultaneous measurement of multiple substances in different infrared wavelength windows tailored to scientific questions related to a particular flight mission. Three OA-ICOS setups have been implemented with the aim to measure OCS, CO2, CO, and H2O at 2050 cm−1; O3, NH3, and CO2 at 1034 cm−1; and HCN, C2H2, and N2O at 3331 cm−1. The 2050 cm−1 setup has been characterized in the laboratory and successfully used for atmospheric measurements during two campaigns with the research aircraft M55 Geophysica and one with the German HALO (High Altitude and Long Range Research Aircraft). For OCS and CO, data for scientific use have been produced with 5 % accuracy (15 % for CO below 60 ppb, due to additional uncertainties introduced by dilution of the standard) at typical atmospheric mixing ratios and laboratory-measured 1σ precision of 30 ppt for OCS and 3 ppb for CO at 0.5 Hz time resolution. For CO2, high absorption at atmospheric mixing ratios leads to saturation effects that limit sensitivity and complicate the spectral analysis, resulting in too large uncertainties for scientific use. For H2O, absorption is too weak to be measured at mixing ratios below 100 ppm. By further reducing electrical noise and improving the treatment of the baseline in the spectral retrieval, we hope to improve precision for OCS and CO, resolve the issues inhibiting useful CO2 measurements, and lower the detection limit for H2O. The 1035 and 3331 cm−1 arrangements have only partially been characterized and are still in development. Although both setups have been flown and recorded infrared spectra during field campaigns, no data for scientific use have yet been produced due to unresolved deviations of the retrieved mixing ratios to known standards (O3) or insufficient sensitivity (NH3, HCN, C2H2, N2O). The ∼100 kg instrument with a typical in-flight power consumption of about 500 VA is dimensioned to fit into one 19 in. rack typically used for deployment inside the aircraft cabin. Its rugged design and a pressurized and temperature-stabilized compartment containing the sensitive optical and electronic hardware also allow for deployment in payload bays outside the pressurized cabin even at high altitudes of 20 km. A sample flow system with two parallel proportional solenoid valves of different size orifices allows for precise regulation of cavity pressure over the wide range of inlet port pressures encountered between the ground and maximum flight altitudes. Sample flow of the order of 1 SLM (standard litre per minute) maintained by an exhaust-side pump limits the useful time resolution to about 2.5 s (corresponding to the average cavity flush time), equivalent to 500 m distance at a typical aircraft speed of 200 m s−1.

Natural and Conventional Cosmetics—Mercury Exposure Assessment

Mercury (Hg) can enter the human body through the respiratory tract and digestive system, but also through the skin. Sources of Hg in the environment can be natural processes, but also human activities, including agriculture, chemical, and pharmaceutical industries. Hg can also enter the body through food, but also with cosmetics that are used for a long time. Therefore, the aim of this study was to evaluate the Hg content in 268 randomly selected cosmetics: Natural and conventional, for face and body. Hg content was determined using an atomic absorption spectrometer (AMA 254, Leco, Prague, Czech Republic). It was shown that the face preparations were characterized by a significantly higher Hg content than the body preparations. No differences in the content of the tested element were found between natural and conventional preparations. Hg could be detected in all samples with concentrations measured from 0.348 to 37.768 µg/kg.

Simultaneous measurement of <i>δ</i>¹³C, <i>δ</i>¹⁸O and <i>δ</i>¹⁷O of atmospheric CO₂ – performance assessment of a dual-laser absorption spectrometer

Using laser absorption spectrometry for the measurement of stable isotopes of atmospheric CO2 instead of the traditional isotope ratio mass spectrometry method decreases sample preparation time significantly, and uncertainties in the measurement accuracy due to CO2 extraction and isobaric interferences are avoided. In this study we present the measurement performance of a new dual-laser instrument developed for the simultaneous measurement of the δ13C, δ18O and δ17O of atmospheric CO2 in discrete air samples, referred to as the Stable Isotopes of CO2 Absorption Spectrometer (SICAS). We compare two different calibration methods: the ratio method, based on the measured isotope ratio and a CO2 mole fraction dependency correction, and the isotopologue method, based on measured isotopologue abundances. Calibration with the ratio method and isotopologue method is based on three different assigned whole-air references calibrated on the VPDB (Vienna Pee Dee Belemnite) and the WMO 2007 (World Meteorological Organization) scale for their stable isotope compositions and their CO2 mole fractions, respectively. An additional quality control tank is included in both methods to follow long-term instrument performance. Measurements of the quality control tank show that the measurement precision and accuracy of both calibration methods is of similar quality for δ13C and δ18O measurements. During one specific measurement period the precision and accuracy of the quality control tank reach WMO compatibility requirements, being 0.01 ‰ for δ13C and 0.05 ‰ for δ18O. Uncertainty contributions of the scale uncertainties of the reference gases add another 0.03 ‰ and 0.05 ‰ to the combined uncertainty of the sample measurements. Hence, reaching WMO compatibility for sample measurements on the SICAS requires reduction of the scale uncertainty of the reference gases used for calibration. An intercomparison of flask samples over a wide range of CO2 mole fractions has been conducted with the Max Planck Institute for Biogeochemistry, resulting in a mean residual of 0.01 ‰ and −0.01 ‰ and a standard deviation of 0.05 ‰ and 0.07 ‰ for the δ13C measurements calibrated using the ratio method and the isotopologue method, respectively. The δ18O could not be compared due to depletion of the δ18O signal in our sample flasks because of storage times being too long. Finally, we evaluate the potential of our Δ17O measurements as a tracer for gross primary production by vegetation through photosynthesis. Here, a measurement precision of <0.01 ‰ would be a prerequisite for capturing seasonal variations in the Δ17O signal. Lowest standard errors for the δ17O and Δ17O of the ratio method and the isotopologue method are 0.02 ‰ and 0.02 ‰ and 0.01 ‰ and 0.02 ‰, respectively. The accuracy results show consequently results that are too enriched for both the δ17O and Δ17O measurements for both methods. This is probably due to the fact that two of our reference gases were not measured directly but were determined indirectly. The ratio method shows residuals ranging from 0.06 ‰ to 0.08 ‰ and from 0.06 ‰ to 0.1 ‰ for the δ17O and Δ17O results, respectively. The isotopologue method shows residuals ranging from 0.04 ‰ to 0.1 ‰ and from 0.05 ‰ to 0.13 ‰ for the δ17O and Δ17O results, respectively. Direct determination of the δ17O of all reference gases would improve the accuracy of the δ17O and thereby of the Δ17O measurements.

METHODS FOR HEATING CONTROL OF GRAPHITE TUBE IN ELECTROTHERMAL ATOMIZER OF ATOMIC-ABSORPTION SPECTROMETER

The research is devoted to the assessment of changes in the degree of blackness (emittance) and electrical resistance of graphite tubes in the electrothermal atomizer of an atomic absorption spectrometer as they wear out. A joint change of these parameters effects on the heating of the atomizer, and, consequently, on the absorption signals of the elements of the periodic table. The heating of the atomizer is controlled by feedback on the temperature, measured using a brightness pyrometer, the measurements of which depend on degree of blackness of the graphite cuvette. Evaluation of the change in the emissivity was carried out by measuring the temperature of the cuvette with a spectral pyrometer, the measurements of which are independent of the emissivity of the controlled object. The electrical resistance, which effects on the heating rate of the cuvette, was calculated after measuring the current and voltage between the contacts of the atomizer. According to the results of the research, we can say that the main contribution to the change in the heating parameters of graphite tubes as they wear out is made by the varying emissivity.