Gallignani Máximo, Ovalles Fernando, Brunetto Maria Del Rosario, Burguera Marcela, Burguera Jose Luis
Laboratorio de Espectroscopia Molecular (LEM), Departamento de Química, Facultad de Ciencias, Universidad de los Andes (ULA), P.O. Box 440, Mérida 5101-A, Venezuela.
Talanta. 2005 Dec 15;68(2):365-73. doi: 10.1016/j.talanta.2005.08.059. Epub 2005 Oct 19.
In this work, a flow analysis-hydride generation-gas phase derivative molecular absorption-(UV) spectrophotometric method has been developed for the direct determination of antimony in aqueous and hydro-alcoholic samples. Antimony (III) from undiluted samples is directly transformed into the gaseous stibine (SbH(3)) form by on-line reaction with sodium tetrahydroborate (NaBH(4)) in acidic medium (HCl). The gaseous phase generated is separated from the liquid phase using a commercial gas-liquid separator, and swept - with the help of a carrier gas (N(2)) stream - into a quartz gas cell (10cm pathlength); where the corresponding absorption spectrum is acquired in a continuous mode over the 190-300nm wavelength range, using a conventional spectrophotometer. A derivative strategy was selected in order to avoid the strong spectral interference of the ethanol vapor on the gaseous SbH(3) absorption spectrum. In this way, the peak height at 223nm of the second order derivative spectrum appears as a clear, clean and interference free analytical signal, which allows the direct determination of antimony. The recovery values obtained from homeopathic formulations (prepared in alcoholic medium) spiked with know amounts of antimony ranged between 97.5 and 103%. The method provides a dynamic range from 0.20 to 30mgSbl(-1). The precision (RDS), evaluated by replicate analysis (n=5) of samples and standard solution containing between 2.5 and 15mgSbl(-1) was in all cases lower than 1.2%. The proposed method was applied to the determination of antimony in commercial homeopathic products ("Antimonium Tartaricum") prepared in hydro-alcoholic medium; and showed to be simple, precise, and accurate.
在本研究中，开发了一种流动分析-氢化物发生-气相衍生分子吸收-（紫外）分光光度法，用于直接测定水性和水醇性样品中的锑。未稀释样品中的锑（III）在酸性介质（HCl）中与硼氢化钠（NaBH₄）在线反应，直接转化为气态锑化氢（SbH₃）形式。使用商用气液分离器将产生的气相与液相分离，并借助载气（N₂）流吹扫到石英气室（光程10cm）中；在190-300nm波长范围内，使用传统分光光度计以连续模式采集相应的吸收光谱。为避免乙醇蒸气对气态SbH₃吸收光谱的强烈光谱干扰，选择了一种衍生策略。这样，二阶导数光谱在223nm处的峰高呈现为清晰、干净且无干扰的分析信号，可用于直接测定锑。从添加了已知量锑的顺势疗法制剂（在酒精介质中制备）中获得的回收率在97.5%至103%之间。该方法的动态范围为0.20至30mg Sb l⁻¹。通过对含有2.5至15mg Sb l⁻¹的样品和标准溶液进行重复分析（n = 5）评估的精密度（相对标准偏差）在所有情况下均低于1.2%。所提出的方法应用于测定在水醇介质中制备的市售顺势疗法产品（“酒石酸锑钾”）中的锑；结果表明该方法简单、精确且准确。
