This paper reports on an unknown yellowish mineral compound found in an archaeological context from Chorrillos cemetery (Calama, Chile) dating to the Early Formative period (800 -200 B.C.). We used optic microscopy, SEM, EDX, 1 H-RMN, 13 C-RMN, and infrared (IR) and Raman spectroscopy to tease out the chemical and molecular composition of the sample. The microscopic images show amorphous yellowish granulates with heterogeneous chemical surfaces.1 H-RMN and 13 C-RMN negative results show that the sample is free of organic matter. The SEM and EDX indicate the presence of arsenic and sulfur in the sample. The IR and Raman analyses suggest the presence of orpiment which is a toxic yellow arsenic sulfide mineral.
We report on the analysis of a red pigment found in a lavish Inca burial from Cerro Esmeralda, Chile, associated with the human sacrifice of two young girls. The outcome shows that the red pigment is mainly cinnabar, with 95% of HgS content. Cinnabar is rarely found in the archaeological record of Chile. Thus, we propose that our results are another line of evidence supporting Iquique's Cerro Esmeralda inhumation as a unique Inca ritual. It was a special lower‐elevation capacocha burial, most probably undertaken to politically and symbolically incorporate the coastal people into the Tawantinsuyo Empire.
A second derivative spectrophotometric method has been developed for the determination of palladium and platinum in mixtures. The method is based on the formation of the platinum and palladium complexes with 3-(2-thiazolylazo)-2,6-diaminopyridine, (2,6-TADAP), in the presence of 1.7 M * To whom correspondence should be addressed. 93 Downloaded by [University of Connecticut] at 04:45 16 September 2013 94 TORAL ET AL.perchloric acid solution, upon heating at 90° C for 30 min and on the subsequent direct derivative spectrophotometric measurement. The zerocrossing approach and the graphic method were used for determination of platinum and palladium, respectively. Each analyte was determinated in the presence of one another in the ranges 8.9xlO" 7 -3.1x10" M for platinum and 4.6xlO" 7 -6.8xlO" 5 M, for palladium. The detection limits achieved (3a) were found to be 2.7xlO' 7 M of platinum and 1.4xlO' 7 M of palladium. The relative standard deviations were in all instances less than 1.0%. In this work is included a study of effect of interferents and the application of the proposed method in synthetic mixtures.
A direct, simple, and practical first-derivative spectrophotometric method is described for simultaneous determination of ascorbic acid and acetylsalicylic acid. The effects of the solvent, excipients, and spectral variables on the analytical signal were investigated. The drugs were determined simultaneously with a 0.01M methanolic hydrochloric acid solution as the solvent, and the signals were evaluated directly by using the zero-crossing method at 245.0 and 256.0 nm for acetylsalicylic acid and ascorbic acid, respectively. The method allows the simultaneous determinations of acetylsalicylic acid and ascorbic acid in the ranges of 6.6 × 10−6 to 1.5 × 10−4M and 3.4 × 10−6 to 2.0 × 10−4M, respectively, with standard deviation of <2.0%. The proposed method was applied to determinations of these drugs in tablets.
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