Dipartimento di Scienze Chimiche e Geologiche Centro Grandi Strumenti and INSTM unit, Università di Cagliari, Monserrato, Cagliari, Italy.
Anal Bioanal Chem. 2012 Aug;404(3):821-33. doi: 10.1007/s00216-012-6190-5. Epub 2012 Jul 5.
Three fibrous amphiboles that are not regulated as asbestos--two from Biancavilla (Sicily, Italy) and one from Libby (MT, USA)--were studied in order to establish relationships between surface chemistry and surface reactivity. The three fibrous samples, plus one prismatic fluoro-edenite from Biancavilla that was used for comparison, were investigated by X-ray photoelectron spectroscopy (XPS) in order to obtain their quantitative surface compositions and to determine the chemical environment of the Fe in each case. In particular, the Fe 2p(3/2) peak was fitted and, for the first for these materials, the binding energies of Fe(II) oxide, Fe(III) oxide and Fe(III) oxyhydroxide were identified. Bulk chemistries and Fe oxidation states were obtained from previous studies for the samples from Biancavilla, and were investigated in the present work by electron microprobe (EMP) and (57)Fe Mössbauer spectroscopy (MS) for the sample from Libby. Comparison between surface and bulk data revealed that the sample with the lowest bulk Fe oxidation state was the one most affected by surface oxidation, while the samples with bulk highly-oxidised Fe were showing very high signal of Fe (III) oxy-hydroxide probably due to weathering. The surface reactivities of the fibrous amphiboles were investigated by measuring the production of the [DMPO, HO]• radical adduct using electron paramagnetic resonance (EPR) spectroscopy. Notably, significant chemical reactivity was observed; it was found to be comparable with--or, for the Libby sample, even higher than--that of fibrous tremolite (one of the six asbestos minerals). A positive linear correlation was observed when the production of HO• radical was plotted versus the Fe(II) content on the fibre surface. Data on fibrous tremolite obtained from previous studies were added to substantiate the correlation. These results provide evidence that Fe(II) at the fibre surface controls the production of radicals at the fibre surface. The observed relationship provides further confirmation that Fe topochemistry is strictly related to--though not solely responsible for--the toxicity of asbestos and other fibrous amphiboles that are not regulated as asbestos.
为了建立表面化学性质与表面反应活性之间的关系，研究了三种不属于石棉管制范围的纤维状角闪石，它们分别来自比安卡维拉（意大利西西里岛）和利比（美国蒙大拿州）。为了获得它们的定量表面组成，并确定每种情况下铁的化学环境，对这三种纤维状样品以及比安卡维拉的一种棱柱形氟镁闪石（用于比较）进行了 X 射线光电子能谱（XPS）分析。特别是，拟合了 Fe 2p(3/2)峰，并首次确定了这些材料中 Fe(II)氧化物、Fe(III)氧化物和 Fe(III)氢氧化物的结合能。比安卡维拉样品的体化学成分和铁氧化态是以前的研究得出的，本研究通过电子探针（EMP）和（57）Fe Mössbauer 光谱（MS）对利比样品进行了研究。表面数据和体数据的比较表明，体铁氧化态最低的样品受表面氧化的影响最大，而体铁高度氧化的样品显示出很高的 Fe(III)氢氧化物信号，可能是由于风化。通过电子顺磁共振（EPR）光谱测量[DMPO，HO]•自由基加合物的生成来研究纤维状角闪石的表面反应活性。值得注意的是，观察到了显著的化学活性，发现它与--或对于利比样品，甚至高于--纤维透闪石（六种石棉矿物之一）的化学活性相当。当 HO•自由基的生成与纤维表面的 Fe(II)含量作图时，观察到了正线性相关性。从以前的研究中获得的纤维透闪石的数据被添加进来证实了这种相关性。这些结果表明，纤维表面的 Fe(II)控制着纤维表面自由基的生成。观察到的关系进一步证实，铁的拓扑化学与石棉和其他不属于石棉管制范围的纤维状角闪石的毒性密切相关--尽管不是唯一负责--毒性的因素。
