Neutron activation chromatography

Methods for iodine deterrnination in foods using colorimetry (95,96), ion-selective electrodes (94,97), micro acid digestion methods (98), and gas chromatography (99) suffer some limitations such as potential interferences, possibHity of contamination, and loss during analysis. More recendy neutron activation analysis, which is probably the most sensitive analytical technique for determining iodine, has also been used (100—102). 

It is seen by examination of Table 1.11(b) that a wide variety of techniques have been employed including spectrophotometry (four determinants), combustion and wet digestion methods and inductively coupled plasma atomic emission spectrometry (three determinants each), atomic absorption spectrometry, potentiometric methods, molecular absorption spectrometry and gas chromatography (two determinants each), and flow-injection analysis and neutron activation analysis (one determinant each). Between them these techniques are capable of determining boron, halogens, total and particulate carbon, nitrogen, phosphorus, sulphur, silicon, selenium, arsenic antimony and bismuth in soils. 

The section Analysis starts with elemental composition of the compound. Thus the composition of any compound can be determined from its elemental analysis, particularly the metal content. For practically all metal salts, atomic absorption and emission spectrophotometric methods are favored in this text for measuring metal content. Also, some other instrumental techniques such as x-ray fluorescence, x-ray diffraction, and neutron activation analyses are suggested. Many refractory substances and also a number of salts can be characterized nondestructively by x-ray methods. Anions can be measured in aqueous solutions by ion chromatography, ion-selective electrodes, titration, and colorimetric reactions. Water of crystallization can be measured by simple gravimetry or thermogravimetric analysis. 

Other frequently used methods for determining fluoride include ion and gas chromatography [150,204,205] and aluminium monofluoride (AIF) molecular absorption spectrometry [206,207]. Less frequently employed methods include enzymatic [208], catalytic [209], polarographic [210] and voltammetric methods [211], helium microwave-induced [212] or inductively coupled plasma atomic emission spectrometry [213], electrothermal atomic absorption spectrometry [214], inductively coupled plasma-mass spectrometry [215], radioactivation [216], proton-induced gamma emission [217], near-infrared spectroscopy [218] and neutron activation analysis [219]. 

Serum Br, Cu, Fe, I, Mn, Se, Rb, V and Zn Cu, Zn Zn A1 Neutron activation GFAAS, Immunonephelometry GFAAS, Affinity chromatography, Kinetic immunoturbidimetry GFAAS, Ultrafiltration Detailed examination of the behaviour of the elements during fractionation and the effect of contamination in the reagents and equipments 41) 36) 42) 43)... 

ECD = electron capture detection GC = gas chromatography GPC = gel permeation chromatography HRMS = high resolution mass spectrometry LC = liquid chromatography MS = mass spectrometry NAA = neutron activation analysis NCI = negative chemical ionization PBDEs = polybrominated diphenyl ethers... 

Uranium. Perricos and Belkas (25) have determined uranium in six coals by neutron activation followed by separation of the uranium daughter neptunium-239 by carrier-free extraction chromatography. The coals, from mines in northern Greece, had very high uranium concentrations (0.012-0.037%). However, uranium at the few parts per million level found in most coals could no doubt be determined by a modification of this method. 

The determination of lanthanum in soil by neutron activation analysis is discussed under Multi-Metal Analysis of Soils in Sects. 2.55 (neutron activation analysis) and 2.55 (column chromatography). 

With few exceptions, the results given by fluorometry, chromatography and neutron activation analysis compare well with those obtained by inductively coupled plasma atomic emission spectrometry. The precisions obtained for the various samples were very good for between- and within-batch samples. 

Bern [210] has reviewed methods developed up to 1981 for the determination of selenium in soil. These methods include neutron activation analysis, atomic absorption spectrometry, gas chromatography and spectrophotomet-ric methods. Square-wave cathodic stripping voltammetry has been used to determine selenium in soils [212],... 

Inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry have been applied to the determination of zinc, as discussed under Multi-Metal Analysis of Soils in Sects. 2.55 (inductively coupled plasma atomic emission spectrometry) and 2.55 (inductively coupled plasma mass spectrometry). Other techniques include atomic absorption spectrometry (Sect. 2.55), X-ray fluorescence spectroscopy (Sect. 2.55), electron probe microanalysis (Sect. 2.55), photon activation analysis (Sect. 2.55), emission spectrometry (Sect. 2.55), neutron activation analysis (Sect. 2.55), spectrophotometry (Sect. 2.55) and ion chromatography (Sect. 2.55). 

In addition, some metals may be determined by other methods, including ion-selective electrode, ion chromatography, electrophoresis, neutron activation analysis, redox titration, and gravimetry. Atomic absorption or emission spectrophotometry is the method of choice, because it is rapid, convenient, and gives the low detection levels as required in the environmental analysis. Although colorimetry methods can give accurate results, they are time consuming and a detection limit below 10 pg/L is difficult to achieve for most metals. 

AMS = accelerated mass spectroscopy EDTA = ethylene diamine tetra acetic acid GFAAS = graphite furnace atomic absorption spectrometry ICP-AES = inductively coupled plasma - atomic emission spectroscopy NAA = neutron activation analysis ETAAS = electrothermal atomic absorption spectrometry SEC/ICP-MS = size-exclusion chromatography/ICP-AES/mass spectrometry HLPC/ICP-AES = high-performance liquid chromatography/ICP-AES LAMMA = laser ablation microprobe mass analysis NA = not applicable ppq = parts per quadrillion... 

A wide array of laboratory techniques and instrumentation is used in forensic studies. This includes ultraviolet, infrared, and visible spectrophotometry neutron activation analysis gas chromatography and mass spectrophotometry high pressure liquid chromatography and atomic absorption spectrophotometry. The techniques and instrumentation chosen depend on the type of sample or substance to be examined. 

A1 As Be Co, Mo, V Cu, Pb cio2 Ge Pb trace metals U, Th, Po, Ra Organic compounds in water include the following (122) spectrofluorometric, neutron activation hplc coupled to icp / aes AAS icp / aes potentiometric ion chromatography preconcentration reaction followed by spectrophotometry preconcentrated as various complexes OC-spectroscopy and liquid scintillation... 

Ion Chromatography Plasma Spectroscopy Neutron Activation Analysis Proton-Induced Xray Emission... 

NOTE All values are given as weight percent ( 95% confidence limit). Sulfate and chloride were analyzed by ion chromatography carbonate was analyzed by classical titration and calcium, magnesium, chlorine, aluminum, and sodium were analyzed by neutron activation analysis. 

APDC = ammonium pyrroiidine dithiocarbamate Bq = Bequerei and 1 pCi = 0.37 Bq dpm = disintegration per minute and 1 pCi = 2.22 dpm EDTA = ethyienediaminetetraacetic acid Fi = fiow injection HPLC=high performance liquid chromatography ICP = inductively coupled plasma spectrometry INAA = instrumental neutron activation and analysis MS = mass spectrometry NAA = neutron activation analysis nM = nanomole or 10 of a mol... 

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