Acid digestion apparatus

Method 1 Hydrochloric acid digestion sulfur apparatus (for acid-digestible inorganic sulfur) with digestion-distillation flask [73]. 

In general, organic extraction and acid digestion use different types of microwave apparatus, as these two processes require different reagents and different experimental conditions. A new commercial system, Mars X (CEM Corp., Matthews, NC) offers a duel unit that can perform both proce-... 

The titanium contents of the resulting catalyst samples were determined with an inductively coupled plasma-atomic emission spectrometer (ICP-AES) (Kon-tron, Germany Model S-35) after HE acid digestion of the solid. N2 adsorption/ desorption isotherms at 77 K were obtained using a Micromeritics ASAP 2020 apparatus. Catalyst crystalline structure was examined by X-ray diffraction (XRD) on a Shimadzu XRD-6000 diffractometer with Cu Ka radiation. X-ray photoelectron spectroscopy (XPS) data were acquired on a VG Microtech MT-500 spectrometer using A1 Ka X-ray radiation (1,486.6 eV). Fourier transform infrared (FUR) data were obtained on a Shimadzu IR Prestige FUR spectrophotometer. 

Acid Digestion. The digestion apparatus (Figure 12.1) is a modification of that reported to retain quantitatively fig quantities of mercury during the add decomposition of cocoa (27). A separate addition funnel... 

Sulphuric acid is highly corrosive and irritating, particularly to skin, eyes and internal organs, e.g. breathing and digestive apparatuses. 

Note 1. Pick up of ammonia impurity from laboratory atmosphere. The apparatus used for steam distillation from alkali to recover ammonia from the acid digest is fitted with an activated silica gel guard tube. This prevents contamination of the distillate with any ammonia impurity that is present in the laboratory atmosphere. 

In a similar procedure [32] the sediment is wet oxidised with dilute sulphuric acid and nitric acids in an apparatus in which the vapour from the digestion is condensed into a reservoir from which it can be collected or returned to the digestion flask as required. The combined oxidised residue and condensate are diluted until the acid concentration is IN and nitrate is removed by addition of hydroxylammonium chloride with boiling. Fat is removed from the cooled solution with carbon tetrachlodithizone in carbon tetrachloride. The extract is shaken with 0.1M hydrochloric acid and sodium nitrite solution and, after treatment of the separated aqueous layer with hydroxylammonium chloride a solution of urea and then EDTA solution are added to prevent subsequent extraction of copper. The liquid is then extracted with a 0.01% solution of dithizone in carbon tetrachloride and mercury estimated in the extract spectrophotometrically at 485nm. 

Two arguments can he put forward in favour of wet chemical decomposition methods in open vessels, firstly, price, and, secondly, sample throughput. A wet decomposition can, if necessary, be performed with a beaker and a heating plate, whereas apparatus for modem high performance decompositions can cost as much as 25 000. With respect to sample throughput, the automatic wet digestion device can be used for up to 1 SO samples per hour for some materials. Such throughput cannot be realized by any other method. Some special cases exist that necessitate decomposition in open vessels (for instance, when the sample needs to be treated with perchloric acid). 

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