Perchloric acid digestion

Safety While we list safety last, safety must always be at the top of the list of considerations. For example, you should not even consider a method requiring perchloric acid digestion for sample preparation unless your facility has the appropriate quality fume hood. In Table 21.10, we have listed some of the many safety issues you need to evaluate. 

Determination of total phosphorus in lake sediments by ignition of samples in a muffle furnace at 550°C, boiling of the residue from ignition in lmol L 1 hydrochloric acid, and subsequent determination of orthophosphate gave approximately the same values as the perchloric acid digestion. 

Dobolyi and Bidlo [76] have described methods for the determination of phosphorus in lake sediments. Shulka et al. [75] investigated the interference by arsenic in the perchloric acid digestion procedure of Murphy and Riley [85] for the determination of phosphorus in sediments. Arsenite concentrations up to 20pg did not interfere but arsenate interfered. Between 1 and 45 pg arsenic g"1 was extracted from a lake sediment and in all cases the error in the determination of phosphorus due to the presence of arsenic was less than 1%. 

Sulphuric acid-perchloric acid digestion-spectrophotometry Toluene extraction, bromo derivitization, glc Cold vapour aas... 

For platinum compounds, the nitric/perchloric acid digestion mixture used in NIOSH procedure S-191 was replaced with aqua regia to solubilize platinum metal. Platinum dioxide was solubilized by first heating the compound to >380°C to convert the Pt02 to the aqua regia-soluble forms of platinum metal and platinum monoxide. 

Nitrogen determination by perchloric acid digestion of coal without catalysts is reportedly safe and much more rapid than the conventional Kjeldahl procedure. Nitrogen is determined in the digest by the usual ammonia evolution and titration. However, extreme care should be taken whenever perchloric acid is used. Nuclear reactions have been applied successfully to the determination of nitrogen in coal. 

This element has been determined in perchloric acid digests of plant materials by a spectrophotometric procedure as permanganate ion obtained by oxidation with periodic acid or by AAS using the 279.5 nm emission line [28]. 

Bismuth, antimony, arsenic, arsenate, vanadate, thallium, lead, tin, dichromate, nitrate and iron all interfere in this procedure but the interferences by all of these except thallium, tin and dichromate can be overcome by suitable modifications to the method. Plant digests for analysis when prepared by nitric acid-perchloric acid digestion [70]. 

Both solution samples and spiked filter samples containing Cr (III) and Cr (VI) as Cr y were prepared. Samples were solubilized using both a nitric acid and a nitric-perchloric acid digestion. 

Excluding the data for Mo, Pd, and Cr analyzed with a lean air-acetylene flame, the data of Table XII show fewer significant effects than the data of Table XIII. This indicates that a single-step nitric digestion is less sensitive to changes in the variables studied than is a mixed nitric-perchloric acid digestion. 

The data show that a chloride matrix is essential for the digestion of Pd. Therefore, the more vigorous the HNO-j digestion or the more HNO3 present in the nitric-perchloric acid digestion, the less Pd is recovered. 

The less vigorous nitric-perchloric acid digestion did not lower the recovery of Cr. This suggests that acceptable Cr recoveries can be obtained using a perchloric acid digestion as long as both perchloric and nitric acids are present in solution. Losses occur when a solution containing only perchloric acid is taken to small volume. 

The optimization of the atomic absorption method of determining metals in particulates found in the air of workplace is described. The Plackett-Burman Youden-Steiner balanced incomplete block designs as well as single-factor experiments were utilized with ten metals Be, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, and Pd. Of the parameters tested, perchloric acid digestion, flame-stoichiometry, and the composition of the calibration standards were the most significant. Perchloric acid affected the recoveries of chromium. This was attributed to the formation of volatile chromylchloride. Flame-related phenomena and interelemental effects were brought under control using lanthanum flame buffer. 

The authors do not recommend that anyone attempt the use of perchloric acid digestions unless previously trained by an experienced chemist and fully aware of all necessary safety precautions. 

The analysis of nitric-perchloric acid digests of feed samples for a local industry presented an early test of the ICAP analysis of organic samples. The results obtained for Association of American Feed Control OflBcials (AAFCO) feed check samples (included as quality assurance standards within the sample suite) are given in Tables V and VI. The ICAP results for iron, copper, zinc, manganese, cobalt, and potassium are all within the uncertainty limits of the certified values. While not within the uncertainty limits, the results for calcium, magnesium, sodium, and phosphorus compare with acceptable agreement for the intended application. 

In 1966 Kraml (K7) published a procedure for determining phospholipids on perchloric acid digests of the lipid extract. This investigator uses the extraction procedure of Bloor or the trichloroacetic acid precipitation technic of Zilversmit and Davis (Zl). Digestions are carried out on a hot plate for 15 minutes at 200°-225°C in the presence of 1.2 ml of 70% HCIO4. After cooling, the volume is made up to 5.0 ml. The final perchloric acid concentration is 14%, based on the assumption that... 

The total content of the elemental phosphorus in soils can be extracted and determined by perchloric acid digestion followed by spectrophotometric determination. 

Nitric-perchloric acid digestion HCI reduction sodium borohydride reduction measure selenium hydride HGAAS No data 33-73% Oster and Prellwitz 1982... 

Although perchloric acid does not dissolve organic compounds, it digests them. This section is added here to help overcome the fear of using perchloric acid digestions of organic compounds. If handled properly, perchloric acid is the most efficient method available to destroy organic... 

The liquid fire reaction is the most common method to do a perchloric acid digestion and is the safest. The initial reaction mixture is 3 parts concentrated HNO3 and 1 part HCIO4 with 1 mg/mL NH4VO3. 

Siu KWM and Berman SS (1983) Elimination of perchloric acid digestion of biological fluids for fluo-rometric determination of selenium. Anal Chem 55 1605-1606. 

Dabeka RW and McKenzie AD (1986) Graphite-furnace atomic absorption spectrometric determination of lead and cadmium in food after nitric-perchloric acid digestion and copredpitation with ammonium pyrrolidine dithiocarbamate. Can J Spectrosc 31 44-52. 

Perchloric acid digestion of solids retained by 0.45 membrane filter followed by colorimetry Acid hydrolysis of 0.45 fi membrane filtered sample followed by colorimetry... 

PP is the total phosphorus associated with particulate matter. Total phosphorus in the particulate matter is determined by either wet ashing or perchloric acid digestion methods. PP often includes inorganic forms such as phosphate sorbed onto suspended clay particles, and suspended crystalline and amorphous precipitates of PO with Ca, Mg, Al, and Fe. Inorganic phosphorus associated with PP is termed as PIP. Particulate matter is extracted with 1M HCl and filtered solutions are analyzed for orthophosphate as described above. 

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