Determination of gold in alloys via potentiometric titration; an alternative to the fire assay

In this paper we report the results of a deep investigation of gold title in jewellery alloys by means of potentiometric titration. After reviewing the suitable reactions for such purpose we focused on the most profitable one, which involves the use of hexadecylpyridinium chloride (CPC). This cation gives rise to selective and quantitative precipitation of AuCl4 −. We completely revised a method previously proposed by W.S. Selig in the 80's, by improving the sampling preparation and by optimizing the titration steps. Then, the new proposed method was tested on a large number of different alloys, commonly used for goldsmithery purposes. The obtained gold titles were compared with the data achieved by fire assay, giving rise to a very good agreement. At the light of these results, the present method can be rightfully considered a cheaper and "greener" alternative to the traditional one

Synchronous gastric adenocarcinoma and pancreatic ductal adenocarcinoma.

BACKGROUND: The association between gastric and pancreatic carcinoma is a relatively rare condition. In gastric carcinoma patients, the prevalence of second tumors varies 2.8% to 6.8% according to the reported statistics. Gastric cancer associated with pancreatic cancer is uncommon. METHODS: We report a case of a 73-year-old patient hospitalized for vomiting and weight loss. Esophagogastroduodenoscopy demonstrated an ulcerative lesion of the gastric antrum. Computed tomography and magnetic resonance showed a gastric thickening in the antral and pyloric portion and a nodular mass (3 X 1.7 cm) in the uncinate portion of the pancreas. RESULTS: The patient underwent pancreaticoduodenectomy according to Whipple regional type I Fortner. Histological examination of the specimen demonstrated a moderately differentiated adenocarcinoma of the stomach and a poorly differentiated ductal adenocarcinoma of the pancreas. CONCLUSIONS: Long survival is rare in patients with associated gastric and pancreatic cancer. Surgical resection remains the only potentially curative treatment