Apparatus Arsenic

Procedure. The arsenic must be in the arsenic (III) state this may be secured by first distilling in an all-glass apparatus with concentrated hydrochloric acid and hydrazinium sulphate, preferably in a stream of carbon dioxide or nitrogen. Another method consists in reducing the arsenate (obtained by the wet oxidation of a sample) with potassium iodide and tin(II) chloride the acid concentration of the solution after dilution to 100 mL must not exceed 0.2-0.5M 1 mL of 50 per cent potassium iodide solution and 1 mL of a 40 per cent solution of tin(II) chloride in concentrated hydrochloric acid are added, and the mixture heated to boiling. 

This apparatus may also be adapted for what are termed hydride generation methods (which are strictly speaking flame-assisted methods). Elements such as arsenic, antimony, and selenium are difficult to analyse by flame A AS because it is difficult to reduce compounds of these elements (especially those in the higher oxidation states) to the gaseous atomic state. 

Tao et al. [658] have described a procedure in which antimony and arsenic were generated as hydrides and irradiated with ultraviolet light. The broad continuous emission bands were observed in the ranges about 240-750 nm and 220 - 720 nm, and the detection limits were 0.6 ng and 9.0 ng for antimony and arsenic, respectively. Some characteristics of the photoluminescence phenomenon were made clear from spectroscopic observations. The method was successfully applied to the determination of antimony in river water and seawater. The apparatus used in this technique is illustrated in Fig. 5.16. 

Figure 10.1. Apparatus for the evolution and trapping of arsenic. The dimensions of the absorption tube F are given in the inset. Source [17]...

Materials Required Arsenic limit test apparatus HgCl2—paper smooth white filter paper (having thickness in mm of 400 paper = weight in g per Sq. M.), soaked in a saturated solution of HgCl2, pressed to get rid of excess of soln. and dried at about 60°C in the dark lead acetate solution 10.0% w/v soln. of PbAc2 in C02 free water KI (AsT), 1.0 g Zn (AsT) 10.0 g Dilute Arsenic solution (AST) Standard stains, Test Solutions—are prepared according to the Indian Pharmacopoeia 1996. 

Simmonds JS VITA time estimation apparatus control data on 10 normal volunteers. Edgewood Arsenal Technical... 

Antoine Baum , 1728-1804. French pharmacist and chemist. Author of a Chymie expenmentale et raisonnee in which he discussed chemical apparatus, chemical affinity, fire, air, earth, water, sulfur, gypsum, alum, clay, niter, gunpowder, borax, arsenic, glass, porcelain, and the common acids, alkalies, metals, and ores used m 1773. His hydrometer scale is still used. He was one of the first chemists to investigate platinum... 

IMPACT SENSITIVITY OR SHOCK SENSITIVITY TESTS (Drop Weight or Falling Weight Tests). A list of various tests with refs is given in Vol 1, p XVII. Brief descriptions of US Bureau of Mines (BM) Apparatus and of Picatinny Arsenal (PA) Apparatus are also given on p XVII. British test called Figure of Insensitiveness (FI) is described on p XII (See also Refs 36, 38d, 41, 42, 53, 55b,... 

A.J. Clear, "Standard Laboratory Procedures for Determining Sensitivity, Brisance and Stability of Explosives", PATR 3278 (Dec 1965) [Superseding PATR FRL-TR-25 (l )6l] Impact Test with Picatinny Arsenal Apparatus (pp 2-4 and Figs 1, 2, 3 4, pp 32-35) Impact Test with US Bureau of Mines Apparatus (pp 4-7 and Figs 5, 6 7, pp... 

Fig 5—2. Parts of Picatinny Arsenal Impact Test Apparatus... 

Note A.J.Clear gives in PATR 3278 (1965) detailed descriptions of Impact Test with Picacinny Arsenal Apparatus (pp 2-4 with Fig 4 on p 35) and "Impact Test with US Bureau of Mines Apparatus (pp 4-7 with Fig 7 on p 38). He also describes on p 7 "Modified Impact Tests for Liquid Explosives", made with US Bureau Mines and PicArsn Apparatuses... 

By the action of nascent hydrogen upon soluble arsenic compounds, as by the introduction of arsenious acid into on apparatus evolving hydrogen —... 

Picatinny arsenal (PA) impact apparatus The sample which is placed in the depression of a small steel die-cup and then capped by a thin brass cover, is used in this test. The value of minimum height at which at least one out of ten trials results in explosion gives impact sensitivity. In the case of liquids, it is filled in a die-cup and tested in a manner similar to solids. 

To prepare arsenic hydride, assemble an apparatus as shown in Fig. 140 and perform this experiment as described under the heading Preparation of Antimony Hydride in Sec. 31.2. Write the equations of all the reactions proceeding in this experiment and explain them. 

More consistent results than some obtained with the B of M machines are obtd with an apparatus used for many years at Picatinny Arsenal(Refs 4,13,15 16). With this machine, known as Picatinny Arsenal Impact Apparatus, samples are tested under confinement aed results are reported In inches. The usual weight hammer is 2 kg for HE s and smaller wts of 1 lbor 8 ox for initiating expls. Fora description of apparatus and procedure, see Refs 13.15 16... 

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