Screening methods nitrates

Nitrate can also be measured potentiometrically with an ion-selective electrode at 10 10 M (24,25). This method is suggested as a screening method for determining the approximate nitrate concentration (20). Ion chromatography can be used for nitrate concentrations of 2 to 10 ppb (23). 

X. Xu, A.M. van der Craats and P.C.A.M. de Bmyn, Highly sensitive screening method for nitroaromatic, nitramines and nitrate ester explosives by high performance liquid chromatography — atmospheric pressure ionization — mass spectrometry (HPLC-APl-MS) in forensic applications , J. Forensic Sci., 49 No. 6 (2004) 1171-1180. 

Using a radial compression Q8 column and a mobile phase of aqueous tetramethylammonium phosphate Kok et al. [320] analysed mixtures of nitrate and nitrite at the O.lmg L 1 level (3a) and compared the results obtained with those found by ultraviolet spectroscopic screening methods. 

Separation and washing of picric acid Drying and screening Dinitrophenol nitration method... 

In this method, the herbage is first dried at 50 °C for 48 hours and milled to pass though a 0.5 mm screen. Ground material (1 g) is combined with magnesium nitrate solution, which acts as an ashing acid, and the mixture is ignited at 200 °C for 30 minutes and then at 450 °C for 5 -15 hours. The ignited residue is treated with potassium iodide and then dissolved in concentrated hydrochloric... 

Screenings the apparatus consist of a fixed-bed reactor containing Ig of catalyst. Hydrocarbon feed (carbureactor containing 189 ppm RSH) and air (atmospheric pressure) are passed through the reactor with a space velocity of 1.2 h at room temperature. The residual mercaptan content was determined using the silver nitrate potentiometric method norm [23]. 

A more detailed study of the combustion of methane over a series of Mg doped LaCrOs perovskites has been reported by Saracco et al [63]. The catalysts prepared were LaCri.xMgxOs, where 0 < X< 0.5, and were synthesised by the method denoted as the citrate method , which briefly consisted dissolving the constituent metal nitrates in citric acid solution. After heating the solution the catalyst precursor was obtained and subsequently calcined at 1100°C to produce the final catalyst. Catalysts were screened for activity using 1.5% methane, 18%... 

Fe is the active metal for high-temperature WGS reaction. Hence, we introduced a variety of metal dopants (M = Cr, Mn, Co, Ni, Cu, Zn and Ce) for iron oxide (spinel lattice) and screened their effectiveness for high-temperature WGS reaction [1]. The idea was to examine if ferrite formation can occur with dopants and promote the Fe Fe redox couple. The substitution of Fe sites in the ferrite strucmre with other transition/non-transition/inner transition metal atoms leads to the crystallization of an inverse (or mixed) spinel. The stoichiometry of an inverse spinel can be represented as A(i a)Ba[AaB(2 a)]04, where 8 is the degree of inversion, while A and B represent typical divalent and trivalent cations, respectively. The catalysts were synthesized by coprecipitation method using nitrates as precursors. The synthesized catalysts were evaluated for ultra high temperature WGS reaction in the temperature region 400-550 °C and GHSV 60,000 h- ... 

A dry mixture containing 6 g. of ammonium nitrate and 5 g. of sodium azide is placed in a 200-ml. flask. Any other mixture containing equimolecular quantities of these two salts may be used, but amounts larger than 10 to 15 g. should be avoided unless extreme care be taken to protect the workers from injury. Although no explosion has as yet occurred during the repeated use of this method with the quantities specified here, it is advisable that the operator be protected at all times by a heavy metal or wooden screen with a small observation window of shatterproof glass, f... 

Christiansen et al. developed an HPLC method of screening Norwegian mushrooms for the presence of psilocin and psilocybin. The alkaloids were extracted from powdered dried mushrooms with methanol which contained 10% IN ammonium nitrate (Christiansen et al. 1981). The recovery of psilocybin was at least 98%, whereas the recovery of psilocin was not reported. The analytes were separated on an unmodified silica column using an alkaline eluent (Christiansen and Rasmussen 1983). After separation, the effluent was split to UV and FL detectors, and an EC detector was connected downstream of the UV detector. Psilocybin was identified and determined by both UV and FL detection. EC was optimized for psilocin due to its low concentration in the mushroom. The detection limit of psilocin by EC was 100 and 250 times lower than by UV and FL, respectively. Psilocybin gave only a small response by EC, since it is optimally oxidized at a higher potential. By this method, it was found that Conocybe cyanopus and Pluteus salicinus also contained psilocin and psilocybin (Christiansen et al. 1984). 

Ammonia (distillation, titrimetric, ammonia-selective electrode, phenate method) nitrite (ion chromatography, colorimetric) nitrate (ultraviolet spectrophotometric screening, nitrate electrode, reduction) organic (Kjeldahl, persulfate method) lodimetric and modifications, membrane electrode Acid digestion, colorimetric methods Gravimetric, atomic absorption spectrometry, colorimetric Colorimetry, iodometric, ion-selective electrode Gravimetric, turbidimetric, colorimetric... 

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