The percent recovery of mercury in the cold-vapor atomic absorption analysis of mercury in various biological matrices is measured. Hair digest samples, urine, and fish samples give nearly quantitative recovery. Milk and brain samples give recoveries of approximately 90%, and liver samples 85%.

Animals↗

PubMedDate not supplied

The observation of unusually large blank values in the cold-vapor atomic absorption analysis for total mercury.

Anomalously high blank values (1000 X normal) have been observed when cold-vapor atomic absorption analysis for total mercury follows analysis for inorganic mercury. The origin of this unexpected phenomenon is considered to be accumulated chemisorption and possible deep embedment of mercury from previous samples within the reaction vessel. Detection of this mercury follows CdCl2-induced desorption. Precautionary measures are suggested.

Cold Temperature↗

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Serious complications in the liquid scintillation counting analysis of mercury-203.

The decrease in the count rate of mercury-203 as calculated from its half-life is approximately 0.06% per hour. In actual practice using liquid scintillation counting, this decrease can be far greater. It is shown that fluorescence, adsorption, and chemical reduction followed by volatilization are not responsible for this apparent loss of activity. The origin of the phenomenon is shown to be precipitation in the short term (24 h) followed by surface adsorption of the precipate in the longer term (greater than 2 days).

Chemical Precipitation↗

PubMedDate not supplied

The matrix effect in the cold-vapor atomic absorption analysis of mercury in environmental samples.

In contrast to analyses of biological samples, the cold-vapor atomic absorption determination of mercury in environmental samples exhibits essentially no matrix effect.

Environmental Pollutants↗

PubMedDate not supplied

The effect of experimental parameters on the cold-vapor mercury atomic absorption determination. Speciation analysis of sulfhydryl-bound mercury.

Two schools of thought have dominated the reduction procedure in cold-vapor atomic absorption: acidic reduction following the method of Hatch and Ott (4), and alkaline reduction as devised by Magos and Cernik (5). Our study investigates the effect of cysteine added to both mercury stock solutions and reducing solutions in combination with acidic and alkaline reduction procedures. The results allow the separate identification of mercury in the sulfhydryl complexed and uncomplexed form.

Mercury↗

PubMedDate not supplied

The effects of copper, zinc, mercury, and cadmium on rabbit erythrocytic porphobilinogen synthase in vivo.

The interactions of Zn2+, Hg2+, Cd2+, and Cu2+ with normal and lead-intoxicated rabbit erythrocytic porphobilinogen synthase (PBG-S) were studied in vivo. The results obtained show that each divalent ion has a characteristic effect on the pH-activity relationship of PBG-S. The effects for a given ion were both pH and concentration dependent and were similar to those obtained in vitro. Lead was found to be the most potent effector in vivo.

Animals↗

PubMedDate not supplied

Cold-vapor mercury atomic absorption spectrometry: HCl as the cause of the double peak phenomenon.

An investigation has been made on the intermittent second peak that occurs in cold-vapor mercury atomic absorption spectrometry. Evidence that this peak is due to hydrogen chloride gas is presented. Analytical determination of mercury should therefore not include this peak, and a means to suppress or eliminate it, using glass wool adsorption between the reaction vessel and the spectrometer, is suggested.

Hydrochloric Acid↗

PubMedDate not supplied

Elimination of the matrix effect in the cold-vapor atomic absorption analysis of mercury in human hair samples.

The percent recovery of mercury from human hair digest samples, using the peak height cold-vapor atomic adsorption method is 73.0% +/- 10.3%. This value and its reproducibility are raised to 102.2% +/- 6.3% by use of peak area measurements in place of peak height. The so-called matrix effect is thus eliminated, and its origin shown to be in the slower (but still quantitative) release of mercury from biological samples. Although greater reliability is obtained using peak area, this is gained at the cost of analysis time.

Hair↗

PubMedDate not supplied

Interferences in the delta-aminolevulinic acid dehydratase (ALA-D) assay.

A systematic study of the effect of procedural variables on the ALA-D assay has been carried out. Because of metal content in vacutainers, artifactual results are obtained on blood samples drawn by this method and the method of choice is the use of plastic syringes and tubes. The use of isopropyl alcohol as a skin sterilizing agent, although it gives measurable blood alcohol readings, does not affect the ALA-D assay. The handling of the whole blood has been investigated and the two methods of hemolysis compared. Trichloroacetic acid, a reagent used in the final assay of porphobilinogen, has been found to be a serious interference in the method, making it essential for this reagent to be kept in a securely sealed container. The deterioration of the trichloroacetic acid--mercuric chloride reagent is also a potential procedural problem that must be considered.

1-Propanol↗

PubMedDate not supplied

Assessment of the methods available for the determination of carbon monoxide in blood.

Experimental evaluation of methods for assessing the carboxyhemoglobin (COHb) content in blood using gas chromatography, UV-visible spectrophotometry (three methods), and magnetic circular dichroism (MCD) has been made. From the point of view of measurements where the COHb content is low (less than 15%), elevated simply by the smoking population, the spectrophotometric method by Rodkey, et al. (7) emerges as the most satisfactory. MCD analysis, however, is potentially considerably simpler, not requiring chemical pretreatment of the blood, and provided that analysis time can be improved, is likely to replace the spectrophotometric method as the method of choice.

Carbon Monoxide↗

PubMedDate not supplied

Effect of alcohol and carbon monoxide on the pH-activity relationship of erythrocytic delta-aminolevulinate dehydratase (ALA-D).

The effect of blood alcohol on the pH-activity profile of ALA-D in humans and rabbits has been measured. The shape of the pH-activity profile remains unchanged, although enzyme activities are significantly affected (up to 40%). In order for the blood lead assay using ALA-D to remain independent of the presence of alcohol, an alternative methodology, such as a ratio of activities at two pH values, and not a measurement at a single pH value should be used. The effect of carbon monoxide on the pH-activity profile of ALA-D, on the other hand, is minimal.

Animals↗

PubMedDate not supplied

Automation of the Magos mercury determination.

Explore the source record for details and available documents.

Autoanalysis↗

PubMedDate not supplied

Speciation of trace quantities of mercury using a double Magos determination.

Aqueous solutions containing zero-valent and divalent mercury may be analysed using a double-Magos determination. Results are compared with standard methodology incorporating determinations of divalent mercury, by the dithizone technique, and of total mercury. Excellent correlations of Hg2+ concentrations by the two methods were obtained; the scatter in the comparison of Hg0 determinations was interpreted in terms of the substantial error unavoidably present in the standard methodology. The new method represents a significant improvement.

Dithizone↗