Po In Samples Research Articles

Analisis Kadar Nitrogen Total pada Pupuk Padat dengan Metode Kjedahl di Balai Pengkajian Teknologi Pertanian (BPTP) Yogyakarta

Telah dilakukan analisis penentuan kadar N-Total dalam pupuk di Balai Pengkajian Teknologi Pertanian (BPTP) Yogyakarta. Penelitian ini bertujuan untuk mengetahui kadar nitrogen total dalam sampel pupuk. Analisis kadar nitrogen dalam pupuk dilakukan dengan mengggunakan Metode Kjeldahl. Prinsip penentuan nitrogen total dengan metode Kjeldahl adalah nitrogen dalam sampel pupuk dihidrolisis dengan asam sulfat pekat membentuk senyawa amonium sulfat. Produk hasil destruksi yaitu senyawa ammonium sulfat didestilasi dalam suasana basa yang kemudian ditampung dengan asam borat. Destilat yang dihasilkan dititrasi dengan larutan asam sulfat sampai terjadi perubahan warna hijau menjadi merah muda. Dari hasil kadar N-Total didapatkan yaitu pada sampel PO.207 dengan N-Total 1,8136%, PO.208 dengan N-Total 1,5597%, PO.209 dengan N-Total 1,5489%, PO.210 dengan N-Total 1,385%, PO.211 dengan NTotal 1,1292% dan PO.212 dengan N-Total 2,2401%.

Mössbauer quantification of pyrrhotite in relation to self-heating

Pyrrhotite (Po) is widely considered the most significant mineral in the self-heating of sulphide ores and concentrates. It is therefore desirable to determine the amount of Po in a sample. This is commonly accomplished through X-ray diffraction (XRD) or quantitative evaluation of materials by scanning electron microscopy (QEM–SEM), neither of which are suited to oxidizing samples such as Po. The sample preparation for these methods often requires heating and drying, which may alter the composition. This paper introduces another quantitative method based on Mössbauer analysis, whose sample preparation is limited, and not as likely to alter the sample. The technique is tested using binary and ternary mixtures containing pyrrhotite with pentlandite (Pn), pyrite (Py) and sphalerite (Sp). A detection limit of 2 wt.% Po is easily obtained in the Po–Pn binary mixtures. The Po is also successfully measured in Pn–Po–Py and Sp–Po–Py mixtures; however, the presence of sphalerite increases the time required for an accurate measurement. The time required to measure Po in complex samples may be optimized through future work.

Quantification of measurement uncertainty in the sequential determination of 210Pb and 210Po by liquid scintillation counting and alpha-particle spectrometry

Methodologies for the quantification of measurement uncertainties associated with the determination of 210Pb- and 210Po-specific activities by liquid scintillation counting (LSC) and alpha-particle spectrometry are presented, and are demonstrated using the soil reference material IAEA-326. Major contributors to the combined uncertainty associated with the measurement result of 210Pb were the uncertainties of net count rates in the 210Pb energy region of the sample spectrum and in the 210Bi energy region of the blank spectrum. The predominant sources of uncertainty in the measurement of 210Po were the uncertainties of net count rates in the regions of interest of 209Po and 210Po. The relative standard uncertainty of 210Po exponentially increases with the time interval between the sampling date and the separation date of Po, and this effect is strongly dependent on the 210Po/210Pb activity ratio. When the specific activity of 210Pb is much higher than that of 210Po in the sample, the relative standard uncertainty of the 210Po determination increases significantly within a short time interval between the sampling date (or reference date) and the separation date of Po in samples.

Negative thermal ion mass spectrometry of oxygen in phosphates

A novel technique for the precise measurement of oxygen isotopes by negative thermal ion mass spectrometry (NTIMS) is presented. The technique is ideally suited to the analysis of oxygen isotopes in phosphates which form intense P03 ion beams. Since P is monoisotopic, the mass spectrum for P0 3 − at 79, 80, and 81 corresponds to 1660, 170, and 180. Natural and synthetic phosphates are converted and loaded on the mass spectrometer filament as Ag 3PO 4 precipitated directly from ammoniacal solution. To lower the work function of the filament, BaCl, is added in a 1:1 molar ratio of PO 4:Ba. Using these procedures, Br − mass interference (at 79 and 81 amu) is eliminated for typical analyses. Experiments with 180-enriched water show less than 1 % O-exchange between sample PO 4 and adsorbed water, and there is no O-exchange with trace OZ present in the mass spectrometer source chamber. The ionization efficiency of PO 4, as P0 3 − is >10% compared to 0.01% for both conventional dual inlet Gas Isotope Ratio Mass Spectrometry (GIRMS) and secondary ion mass spectrometry (SIMS). Therefore, NTIMS offers exceptional sensitivity enabling routine and precise oxygen isotope analysis of sub-microgram samples of PO 4, (<21 nmoles equivalent CO 2 gas) without need for lengthy chemical pre-treatment reproducibility of the sample. Overall external precision is ±1%c (2σ) for 18 O 16 O and 17 0 15 O with of instrumental isotope fractionation (calculated from 18 O 16 O of ±0.5%c amu −1. Small phosphate samples including single mineral grains from meteorites, or apatite microfossils, can be analyzed by this technique.