Absorption nickel

Colorimetric, spectrophotometric and histochemical studies have shown that the homy layer is the epidermal barrier to nickel absorption [270]. The carboxyl groups of the keratin have been found to be important in the binding of nickel [271, 272],... 

Kinetic Parameters for Nickel Absorption, Distribution, and Elimination in Humans 2-7 Genotoxicity of Nickel in Vivo... 

Sunderman et al. (1989b) have developed a model to predict nickel absorption, serum levels, and excretion following oral exposure to nickel in water and food. The model was developed based on two experiments in humans in which serum nickel levels and urinary and fecal excretion of nickel... 

Sunderman FW Jr, Hopfer SM, Sweeney KR, et al. 1989b. Nickel absorption and kinetics in human volunteers. Proc Soc Exp Biol Med 191 5-11. 

Tallkvist J, Tjalve H. 1994. Nickel absorption from perfused rat jejunal and ileal segments. Pharmacol Toxicol 75 233-243. 

Table 7 7.7 Nickel absorption and reduction by sodium dithionite and rongalite for different types of fibres and their electroconductive capacity...

Transfer 10 )li1 of the blood sample to a 10x5 mm nickel crucible (Delves cup), add 10 jiil of water, and heat at 150° for 1 minute or until sputtering occurs. Add 20 li1 of strong hydrogen peroxide solution, and evaporate to dryness at 150°. Place the cup in the air-acetylene flame and imder the nickel absorption tube, and record the absorbance at 217 nm. The correct positioning of the cup is crucial. Repeat the procedure using a series of nickel crucibles containing, individually, 10 ll1 of the pooled normal blood and 10 p, of each diluted standard solution. 

Foulkes EC and McMullen DM (1986) On the mechanism of nickel absorption in the rat jejunum. Toxicology 38 35-42. 

Nielsen GD, and Eesen O, Jensen M and Geandjean P (1986) Gastrointestinal nickel absorption a new experimental model using the gamma-emitting isotope Ni. Proceedings of the UOEH International Symposium on Bio- and Toxico-kinetics of Metals. Univ Occup Environ Health, Kitakyushu. 

Tallkvist J, Wing AM and Tjalve H (1994) Enhanced intestinal nickel absorption in iron-deficient rats. Pharmacol Toxicol 75 244-249. 

The platinum loop-nickel absorption tube technique of White (1969) gave a 2-fold increase in FAAS sensitivity for copper in aqueous solutions. A later modification of this technique (Hartley and Ellis, 1972) allowed nanogram amounts of free copper to be... 

The sampling-boat technique is frequently hampered by poor precision. Delves (D5) described an improved system. He modified the system of White (W5) who used a platinum-wire loop in conjunction with an absorption tube to increase sensitivity. Delves vaporized samples from microcrucibles made of nickel foil into a nickel absorption tube situated in air-acetylene flame. The sensitivity is 1 X g lead per 1% absorption at the 2833 A line. Only 10 /lil of whole blood are required. Before analysis, the sample is dried in the nickel crucible on a hot plate at 140°C (ca. 30 seconds) and then is partially oxidized with 20 jal of 30% hydrogen peroxide at 140°C until a dry yellow residue is obtained. Standards of lead added to normal blood are run in a similar fashion. 

Delves reported on a sampling cup technique to determine lead in blood. The blood is placed in a nickel cup, dried, and oxidized. The sample then is volatilized, using an air-acetylene flame, into a nickel absorption tube mounted parallel to and just above the air-acetylene flame. The instrumental arrangement is shown in Figure 10-22. Delves has reported a sensitivity of 1 x 10 g lead at 1 % absorption and a standard deviation of 4% at the 3-ng level of lead. The sample size most commonly used was 50 fil The nickel absorption tube was 100 mm long with a 12.5 mm inside diameter. 

It is assumed that a supply of fluorine will be available, prepared as described by Simons or Cady. If desired, a small electrolytic generating unit can be purchased ready for operation, or the gas may be obtained in cylinders. A flow of at least 150 ml./min. will be required in the preparations to follow. It is best to remove traces of hydrogen fluoride from the fluorine by means of a cold trap in Dry Ice, followed by a nickel absorption tube containing anhydrous sodium fluoride pellets, maintained at 100 . ... 

Figure 6.7 Most sensitive nickel absorption line at 232.003 nm and two secondary lines at 232.138 nm and 232.195 nm, respectively...

Figure 8.45 Time-resolved absorbance spectrum obtained for a Brazilian crude oil sample as oU-in-water emulsion in the vicinity of the nickel absorption line at 232.003 nm using a pyrolysis temperature of 600 °C, and an atomization temperature of 2400 C...

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