Absorption procedure

Olafsson [427] has described a semiautomated determination of manganese in seawater using leucomalachite green. The autoanalyser had a 620 nm interference filter and 50 minute flow cells. Findings indicated initial poor precision was related to pFl, temperature, and time variations. With strict controls on sample acidity and reaction conditions, the semiautomated method had high precision, at least as good as that achieved by preconcentration and atomic absorption procedures, and provided precise, rapid, shipboard information... 

A fluorometric procedure would be used when analyzing for a substance that is able to fluoresce and when the absorption procedure is prone to interferences and does not give a satisfactory sensitivity. 

Chemical analysis of odorants in ambient air is hampered by the presence of a plethora of volatile organic compounds, which do not contribute to the odour. Nevertheless application of either powerful separation and identification techniques, such as the GC-MS combination, or specific GC-detection or absorption procedures allow qualitative and quantitative determination of odourants. Improvements are under way to achieve the sensitivity necessary for relevant immission concentrations, which go down to 0.1 ppb for some odorants. 

The permanganate solutions obtained from both the coal and ash samples were analyzed by the direct aeration flameless atomic absorption procedure. The concentration in each sample was calculated from the measured mercury value, the blank concentration in the permanganate solutions, and the weight of the samples. 

Yotsuyanagi, T., et al. 1975. Systems approach to vaginal delivery of drugs I Development of in situ vaginal drug absorption procedure. J Pharm Sci 64 71. 

Earlier atomic absorption methods [164-167] from the determination of molybdenum in soils employed a preliminary solvent extraction step to improve sensitivity in view of the low concentrations of molybdenum occurring in most soils. Baucells et al. [5] developed a graphite furnace atomic absorption procedure which was capable of determining down to 8.4 pg of molybdenum in a soil matrix solution with a precision of 4% for 100 pg/1 molybdenum. These workers showed that a char temperature of 1500 °C and an atomisation tem-... 

The determination of dimethylselenides and diethylselenide in scrubbed air samples has been discussed [699], This method is based on a gas chromatographic-atomic absorption procedure and could, no doubt, be adapted for the analysis of waters. 

An alternative to preparing standardized carriers is to purchase certified standards for other analytical methods. For example, standards for atomic absorption procedures have a concentration of 1,000 ppm (mg/L) and could be pipetted in 10-ml aliquots. This choice is suitable if the laboratory analyzes a large number of samples and a certificate is required for the standard solution. 

Moody, R.P. and B. Nadeau (1993). An automated in vitro dermal absorption procedure III in vivo and in vitro comparison with the insect repellent Af,Af-diethyl-w -toluamide in mouse, rat, guinea pig, pig, human and tissue-cultured skin, Toxicol In Vitro, 7, 167-176. 

We developed a procedure for the identification of proteins by CIE with a trap-gel containing monospecific antiserum (11). This procedure can be used with all commercially available antisera, even when made mono-specific by absorption procedures and thus containing antigen excesses. 

The three fractions resulting from the silica gel chromatography of the shale oil neutral naphtha were examined in detail to provide information regarding the degree of cross-contamination of the various fractions. The saturate s fraction was examined by IR, UV, and proton NMR and showed no aromatic or olefinic contamination, but when subjected to the acid absorption procedure it gave a 3% loss. The lack of any UV, IR, or NMR absorptions owing to aromatic or olefinic materials accompanied by the shrinkage upon acid absorption indicates that the nonsaturate material is probably tetra-substituted olefins. The low concentration, however, may... 

There were several observations made concerning the arsenic analysis by both the AgDDC technique and the high-sensitivity atomic absorption procedure during the course of this investigation. Turbidity problems were initially encountered in the AgDDC colorimetric procedure. 

In the atomic absorption procedure 5-10 mg of organoantimony compound is dissolved in 5 ml of butan-2-one, acetone, dimethoxyethane or THF depending on the solubility of the organoantimony compound. Concentrated hydrochloric acid and ethanol are added and the mixture diluted with water. The solution is aspirated into a fuel-rich air-hydrogen or air-acetylene flame and the absorbance measured at 217.6 nm in the flame just above the burner head. The calibration graph is slightly curved over the range... 

Volatile organics, either naturally occurring or sampler-induced, may interfere with adsorption at the mercury wavelength (2537 A) during the usual flameless atomic absorption procedure (4). 

The recent proliferation of government regulations on atmospheric contaminants has demanded the development of sensitive, rapid, and highly specific methods for a variety of chemical compounds. Infrared absorption procedures appear to meet this need better than any other single analytical tool. 

With the introduction of ultraviolet absorption procedures (ASTM D-2008, ASTM D-2269), the test finds less use but still provides a useful method to determine possible contamination of mineral oil with impurities transparent to both visible and ultraviolet light and hence not detectable by color or by ultraviolet absorption measurements. 

The wet point, the first-stage consistency, is determined by kneading a certain amount of pigment with just enough liquid to form a stiff coherent paste. This end point is similar to the results obtained from the Gardner-Coleman rub out oil absorption procedure. The end point will vary with different combinations of pigments and with different vehicles. 

Vinas et al. (1993a), determined copper in biscuits and bread using a fast-program slurry electrothermal atomic absorption procedure and Miller-Ihli (1988) also used EAAS after slurry preparation for simultaneous multi-element AAS, as did Littlejohn et al. (1985) who introduced slurried food samples into the graphite furnace for analysis. Haswell and Barclay (1992), carried out on-line microwave digestion of slurry samples with direct flame atomic absorption spectrometric elemental detection. 

ViNAS P, Campillo N, Gaecia IL and Coedoba MH (1993a) Analysis of copper in biscuits and bread using a fast-program slurry electrothermal atomic absorption procedure. J Agric Food Chem 41 2024-2127. 

The use of high-purity chlorine containing only small amounts of dissolved imf)urities has been shown to be advantageous in preventing formation of undesirable by-products in this chlorination of acetylene. It is believed, however, that this absorption procedure is no longer used because the yield of C2H2CU is relatively low. 

Absorption methods are analogous to optical absorption procedures in which the attenuation of a band or line of X-radialion is the analytical variable. Wavelength selection is accomplished with a monochromator such as that shown in Figure 12-9 or by a filter technique similar to that illustrated in Figure 12-8. Alternatively, the monochromatic radiation front a radioactive source may be used. 

As was pointed out in Chapter 15, an inherent advantage of fluorescence methods is their high sensitivity. which is typically greater by more than an order of magnitude than most absorption procedures. This advantage has been exploited in LC for the separation and... 

The results of this investigation show that the method described can be effectively used when the concentration of metals in water is too low for analysis by normal atomic absorption procedures provided the metals form solvent extractable complexes with sodium diethyldithiocarbamate. We use this method routinely for the determination of iron, lead. 

El. Ediger, R. D., and Goleman, R. L., A modified Delves cup atomic absorption procedure for the determination of lead in blood. At. Absorption Newslett. 11, 33-36 (1972). 

As the format of this new type of raw file is different from the standard SAINT output files,. mul files need a special version of the absorption correction program SADABS (Sheldrick, 1997a), called TWINABS (Sheldrick, 2002). Additionally to the scaling and absorption procedure, TWINABS produces a special twin reflection file (HKLF5 format file) that describes in detail which reflections are affected by overlap. 

Average particle size (nanometers) = (6/BET surface area " x density ") x 1000 Where surface area " is in sq. m/g, and density " " is in g/cc. Micrometries Analytical Services (MAS) will measure BET surface area by a gas absorption procedure and the real density by gas pycnometiy. This gives a good estimate of average primary particle size. For further information see www.micrometitics.com. Micromeritics Analytical Services Downloads. 

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