Studium prvkového rozložení v močových kamenech pomocí spektrometrie laserem buzeného plazmatu

Study of elemental distribution in urinary stones by Laser-Induced Breakdown Spectroscopy

abstrakt

en

The distribution of minor and trace elements in urinary stones, can provide information on their formation. Therefore, analytical methods, which can map the distribution of these elements, should be used. The most common methods include Laser-Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Both of these methods have proved suitable for mapping matrix, minor and trace elements. Another objective was to demonstrate the correlation between matrix elements and trace elements and to determine the minerals content. In some cases the results obtained by laser-ablation based methods were linked to the micro computer-tomography (micro CT)analysis. Each of the investigated urinary stone was cut, sealed into a resin and the cross-section of the sample was polished. Depending on the sample size, the whole cross section or its part was mapped by laser-ablation based analytical methods. On the base of these measurements, for samples containing whewellit or weddellit (or both of these minerals), the correlation between calcium and carbon distribution was confirmed. The correlation between magnesium and phosphorus shows the presence of struvite. The correlation between calcium and phosphorus distribution indicates the presence of apatite. In the case of some samples the fluctuation in the signal for calcium and strontium can be observed. This is probably caused by the substitution of strontium ions into the crystal lattice instead of calcium ions due to the same charge and similar ionic radius. The correlation of zinc, sodium or potassium distribution with phosphates was also observed. They are probably the chemical elements that can be associated with apatite.

Distribuce minoritních a stopových prvků v močových kamenech může přinést informaci o jejich vzniku. Pro tyto účely jsou požívány analytické metody umožňující chemické mapování prvků jako spektroskopie laserem buzeného plazmatu (LIBS) a laserová ablace ve spojení s hmotnostní spektrometrií indukčně vázaného plazmatu (LA-ICP-MS). Obě tyto metody jsou vhodné pro mapování jak matričních, tak minoritních a stopových prvků. Mohou být demonstrovány korelace mezi jednotlivými prvky, případně mohou být výsledky dané do souvislosti se strukturou určenou pomocí počítačové mikrotomografie (mikro CT). Močové kameny byly rozříznuty, zality do epoxidové pryskyřice a řezy byly následně zaleštěny. V závislosti na velikosti vzorku byly buďto celé řezy, nebo jejich části podrobeny mapování laserovými technikami.

The distribution of minor and trace elements in urinary stones, can provide information on their formation. Therefore, analytical methods, which can map the distribution of these elements, should be used. The most common methods include Laser-Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Both of these methods have proved suitable for mapping matrix, minor and trace elements. Another objective was to demonstrate the correlation between matrix elements and trace elements and to determine the minerals content. In some cases the results obtained by laser-ablation based methods were linked to the micro computer-tomography (micro CT)analysis. Each of the investigated urinary stone was cut, sealed into a resin and the cross-section of the sample was polished. Depending on the sample size, the whole cross section or its part was mapped by laser-ablation based analytical methods. On the base of these measurements, for samples containing whewellit or weddellit (or both of these minerals), the correlation between calcium and carbon distribution was confirmed. The correlation between magnesium and phosphorus shows the presence of struvite. The correlation between calcium and phosphorus distribution indicates the presence of apatite. In the case of some samples the fluctuation in the signal for calcium and strontium can be observed. This is probably caused by the substitution of strontium ions into the crystal lattice instead of calcium ions due to the same charge and similar ionic radius. The correlation of zinc, sodium or potassium distribution with phosphates was also observed. They are probably the chemical elements that can be associated with apatite.

Laser induced breakdown spectroscopy; LIBS; elemental distribution; urinary stones

18.07.2011

95–96

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