Soil samples acid digestion

Abbasi [243] described a spectrophotometric method based on N(-pN, N-dimethyl anilo-3-methoxy-2-naphtho)hydroxaminic acid for the determination of vanadium in soil. The soil sample was digested with 8 M hydrochloric acid and potassium permanganate (to oxidise vanadium to the pentavalent state). This extract was retrieved with a chloroform solution of the chromogen and the violet colour was evaluated spectrophotometrically. 

Van Vliet et al. [15] have described a semi-automated procedure for the determination of iodine in soils. The soil sample is digested with 2 N sodium hydroxide, and then the soil is centrifuged off. The resulting solution is digested with perchloric and nitric acid (2 1 v/v) at 265 °C until clear. Iodine is determined in this solution by a method based on the oxidation of arsenic III by cerium IV 3 - 5 ppm mg/kg added to soil was recovered at the 98% level. 

Calculate the concentration (in igg-1) of lead in the soil sample described above. An accurately weighed (2.1270 g) soil sample is digested in 25 ml of concentrated nitric acid, cooled and then quantitatively transferred to a 100 ml... 

Soil, wastes, and groundwater Acid digestion of sample, dilution with water, and filtration AAS (EPA method 7420) GFAAS (EPA method 7421) 0.1 mg/L 1 pg/L No data No data EPA 1986e... 

Wet digestion/ashing Sample heated with strong acid(s) Metals in organic/inorganic solid samples (e.g. metals in soil samples)... 

A chloric acid digestion was used by Backer 2 391 for the preparation of tissue samples. The digest is simply diluted to determine iron, zinc, and copper. The tantalum sampling boat technique was used by Emmermann and Luecke 2531 to measure lead, zinc, and silver in prepared soil solutions. White 1S81 treated ashed plants with hydroxylamine in IN hydrochloric acid to reduce and dissolve oxides of manganese, prior to its determination by atomic absorption spectroscopy. 

Soil samples were sieved to two size fractions <63 pm and <2 mm. Samples were analyzed for multi-element geochemistry by inductively coupled plasma/mass spectrometry (ICP/MS) following a near total 4-acid digestion. 

A total of 112 samples of rock rose (roots and leaves) and 56 soil samples (fraction <0.18 mm) where these plants were grown were analyzed. Soil pH was determined in a soil/water suspension with 1/2.5 (m/v) proportion. Soils and plants were analyzed for Cu, Zn Al, Fe, Mn, Ca, K and P by ICP-OES after digestion with four acids (HCIO4+HNO3+HCI+HF). 

Open vessel digestion (HN03) for bones, teeth, hair, and soil This is a standard preparation for most organic samples. In the case of soils, nitric acid will not fully dissolve all of the sample, but this method is sufficient to examine the total available elements. 

Organic carbon can be determined in calcareous soils after the carbonates have been removed by treatment with sulphuric acid-iron(II) sulphate solution and the samples oven-dried at 105°C. However, as in all other wet-combustion methods, chloride ions interfere [7]. Interference from small amounts of chloride ions (up to 4mg of Ch as KC1 or NaCl) was reduced by adding 2.5% of mercury II oxide or silver I sulphate to the acid digestion mixture. 

Nelson and Sommers [44] have described a Kjeldahl digestion procedure for the determination of total nitrogen in soils in which the sample is digested with sulphuric acid using a selenium catalyst. The digest is steam distilled with sodium hydroxide and ammonia titrated with 3.5mM sulphuric acid. Various other workers have discussed the application of Kjeldahl digestion to the determination of total nitrogen in soils [45-47]. 

Pelts and Belcher [46] have described a semi-automated method for the simultaneous determination of nitrogen and phosphorus in soil. Up to 40 samples are digested with sulphuric acid using a copper sulphate-sodium sulphate catalyst at 370°C for 2.25h in a thermostatically controlled block. Nitrogen is then determined in the 0.2-2.25% range as ammonia by automatic colorimetric analyses of the indophenol blue complex at 630nm. 

Kimura and Miller [29] have described a procedure for the determination of organomercury (methylmercury, ethylmercury and phenylmercury compounds) and inorganic mercury in soil. In this method the sample is digested in a steam bath with sulphuric acid (0.9M) containing hydroxy ammonium sulphate, sodium chloride and, if high concentrations of organic matter are present, potassium dichromate solution. Then, 50% hydrogen... 

The second reason for acid-digestion is the determination of the total soil elemental content of, e.g. potassium, phosphorus or trace elements. This is seldom done for potassium in normal soil samples, mainly because the total K in soils is of no value as an index to the availability of K to plants, nor is it always of value in tracing the movement or accumulation of applied fertilizer K (Pratt, 1965). The unreactive soil phosphorus is obtained by subtracting the naturally leached reactive phosphorus from the total phosphorus, and a method for determining the latter by extraction with sulphuric acid and potassium persulphate is cited by Turner and FHaygarth (2000). They analysed... 

If the analysis is to be carried out in a similar way to total N in herbage, by acid-digestion in test tubes in an aluminium block followed by a colorimetric autoanaiysis procedure, then take a 0.5-g sample of air-dry soil. If serious frothing occurs, take 0.2 g soil, and adjust the calculation accordingly. Reducing the amount to 0.1 g may give peaks which are too small to be read with confidence. See Chapter 7 (pp. 138-141) for details of standards, reagents and method. 

After digesting the soil samples, allow to cool and titrate in the same way. If more than 20 ml of acid-dichromate have been reduced, repeat using less sample. 

The effects of soil sample preparation procedures for the determination of chromium in soils have been reported [38]. The optimum conditions included the use of an homogeneous sample with a mass of less than 4 kg, a grain diameter of less than 0.25 mm, digestion with a solution of nitric acid plus perchloric acid (3 2) and hydrochloric acid after dry ashing, with the addition of 1% lanthanum or 1% ammonium chloride to eliminate interferences. 

Merry and Zarcinas [33] have described a silver diethyldithiocarbamate method for the determination of arsenic and antimony in soil. The method involves the addition of sodium tetrahydroborate to an acid-digested sample which has been treated with hydroxylammonium chloride to prevent the formation of insoluble antimony compounds. The generated arsine and stib-ine react with a solution of silver diethyldithiocarbamate in pyridine in a gas washtube. Absorbance is measured twice at wavelengths of 600 and 504 nm. 

Several acids and acid mixtures have been used for the digestion of soil samples prior to the analysis of lead, including nitric acid-perchloric acid (1 + 1) [105], hydrochloric acid [106], perchloric acid [107], nitric acid-hydrofluoric acid (1 + 1) [ 108,109] and aqua regia [52],... 

Differential pulse anodic scanning voltammetry has been applied to the determination of lead in soils [119]. Sakharov [120] determined lead in soil polarographically by digesting the sample with sodium carbonate, followed by dissolution in hydrochloric acid. He found that when hydrochloric, sulfuric or nitric acids were used as digestion media instead of sodium carbonate, no lead could be detected in the resulting solution. Lead was determined in the digest by anodic scanning voltammetry [121]. 

Floyd and Sommers [142] evaluated a simple one-step digestion procedure for extracting total mercury from soils. The sample was digested with concentrated nitric acid and 4N potassium dichromate for four hours at 55 °C and the mercury in the extract determined by flameless atomic absorption spectrometry. The method can be applied to soils containing up to 20% organic matter. 

Thompson and Zao [170] have described a solvent extraction-inductively coupled plasma atomic emission spectrometric method for the determination of down to 0.02 - 0.03 xg/g of molybdenum in soils. The soil sample is pressure-leached with 6 M hydrochloric acid and at 120 °C for 15 minutes. The digest is then extracted with heptan-2-one to separate molybdenum from potentially interfering elements such as iron, aluminium, calcium and magnesium. This organic extract is then directly sprayed into an inductively coupled plasma atomic emission spectrometer operated at 1.65 to 1.7 kW power. 

Rock, magma, soil, paint, citrus leaves Acid digest sample using Parr bomb or microwave ICP-AES 0.001 g/L 90% Que Hee and Boyle 1988... 

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