Cold Vapour Atomic Absorption Method Research Articles

Total mercury and methylmercury in garfish (Belone belone) of different body weights, sizes, ages, and sexes

BackgroundGarfish, (Belone belone) is a migratory pelagic fish that inhabits the waters of coastal Europe, North Africa, the North Sea, the Mediterranean Sea. Little information about garfish has been disseminated mainly because of its low abundance and its brief occurrence in various water bodies. Data is lacking on mercury compounds, particularly dangerous the toxic organic form of methylmercury (MeHg), which endangers the health of fish and their consumers. MethodsThe research material was garfish caught off the southern Baltic Sea coast in Puck Bay during the spawning period. Total mercury (THg) content was assayed with the cold vapour atomic absorption method in an AMA 254 mercury analyser. The MeHg extraction procedure was based on three-step sequential extraction method: hydrolysis using of hydrochloric acid, extract by toluene, bind the MeHg by L-cysteine. ResultsThe concentrations of THg and MeHg was determined in the muscle of garfish. The highest concentrations of THg (0.210 mg kg-1) and MeHg (0154 mg kg-1) were detected in the longest specimens (80 cm). The THg and MeHg concentrations in garfish muscles increased with specimens length, weight and age, which was confirmed by positive correlations. Differences were also noted depending on sex. Males accumulated more THg and MeHg than did females. The mercury in garfish from the southern Baltic Sea occurred mainly in its organic form MeHg and accounted for 84.7% of the THg. ConclusionSignificant differences were noted in mercury concentrations depends on length, weight, age and sex. Concentration of MeHg in garfish must be done by length class, and fish sex when selecting this fish for contamination studies and risk assessment. The toxic MeHg in garfish tissues did not pose a threat to the health of consumers, as indicated by the low values of EDI, TWI and THQ indices.

A carbon-based fluorescent probe (N-CDs) encapsulated in a zeolite matrix (NaFZ) for ultrasensitive detection of Hg (II) in fish

In this work, a novel strategy was addressed to fabricate new sensing probe (N-CDs@NaFZ) from nitrogen doped carbon dots (N-CDs) confined in Al-free ferrisilicates zeolite (NaFZ) by hydrothermal/solvothermal method. The probe was systematically characterized by HR-TEM, FTIR, energy dispersive X-ray (EDX), powder X-ray diffraction, and UV–Vis absorption and fluorescence spectrophotometers. Characterization of the designed nanocomposite template N-CDs@NaFZ by fluorescence spectrum demonstrates a variety of important conducts as stability improvements, reasonable dispersibility in water, highly emission intensity enhancement at 435 nm when excited at 340 nm, excitation independent fluorescence behaviors, great quantum yield percentage of 91.2%, and narrow size distribution 12 nm, as a nano-space confinement effect of zeolite effectively increase the rigidity of N-CDs. Based on the fluorescence quenching mechanism, the designed approach exhibits an excellent selectivity and good sensitive response to the presence of Hg(II) ions under ambient temperature, with a wide linear range of 0.1–1500 nM and lower detection limits of 5.5 pM. Influences of variables pH and incubation time were optimized. The N-CDs@NaFZ sensor was effectively applied for the detection of Hg(II) ions in the farmed and wild rainbow trout fishes, and the results are in reasonable agreement when compared with that obtained by the cold vapor atomic absorption method.

In situ stabilization of some mercury-containing soils using organically modified montmorillonite loading by thiol-based material

In situ stabilization is a remediation technology that reduces the availability of mercury in contaminated soils by adding chemical substances. In this study, thiol-functionalized montmorillonite modified by organic surfactant (Mont-OR-SH) was used to stabilize soils contaminated with different concentrations of mercury. The Mont-OR-SH used in this study was obtained by grafting the thiol group (–SH) to the montmorillonite modified by organic surfactant (Mont-OR). The physicochemical characteristics were analyzed by XRD, FTIR, and SEM, confirming that the Mont was successfully functionalized, while the concentration of mercury was analyzed by the cold-vapor atomic absorption (CVAA) method. Contaminated soils were mixed with Mont-OR and Mont-OR-SH at different dosages. The effect of stabilization time was investigated when the Mont-OR-SH dosages were 7 wt% and 8 wt%, and five different stabilization pH values were used to investigate the influence on stabilization when the stabilizer dosages was 8 wt%. A sequential extraction procedure and a toxicity leaching procedure were used to evaluate remediation performance. The result indicated that the Mont-OR-SH was effective in stabilizing mercury-contaminated soil, and the stabilization capacity was greatly enhanced upon thiol grafting. Stabilization efficiency for both kinds of soil was greater than 90% after stabilizing by Mont-OR-SH. For two kinds of soils, with a stabilization duration of 14 days, the stabilizer dosage was about 8 wt% and the pH of the leaching was 8.0; the stabilization efficiency could reach 91.7% and 96.7% when stabilized by Mont-OR-SH which is higher than 60.4% and 82.4% when stabilized by Mont-OR. For two kinds of soils, the contents of neutral fraction were reduced and changed to acid fraction, base fraction, sulfide fraction, and residual fraction. Stabilization capacity of Mont-OR was greatly enhanced after the thiol group was loaded; the stabilization process using Mont-OR-SH was effective to treat mercury-containing soils.

Isolation and Characterization of Mercury Resistant <i>Trichoderma</i> Strains from Soil with High Levels of Mercury and Its Effects on <i>Arabidopsis thaliana</i> Mercury Uptake

Traditional mining activities are usually correlated with high levels of soil pollution, which is a major environmental concern. Extensive mining activities have taken place in the San Joaquin region in the State of Querétaro, México resulting in high levels of mercury soil pollution (up to 1532 ± 300 mg/kg). We isolated mercury-resistant fungal strains from the San Joaquin region soils and identified them through morphologic characteristics and ITS rDNA region sequence analysis. We determined that fungi isolated belong to the genus Trichoderma. All the isolates selected showed the ability to catalyze the volatilization of Hg. For air sampling, an active sampling device was constructed and using acid KMnO4 as an absorbent, the concentration of mercury in solution was determined through the cold vapor atomic absorption method. The results show mercury volatilization from the fungal species assay, with a maximum of 213.04 ± 32.6 μg/m3 while mycelium accumulation ranged from less than 17.5 ± 2.9 to 20.0 ± 3.4 μg/g. The fungal isolates were also evaluated for their ability to reduce mercury uptake in Arabidopsis thaliana. These observations suggest the utility of Trichoderma for the mobilization of mercury in those contaminated soils.

New transverse Zeeman effect method for mercury detection based on common mercury lamp

The accurate background correction can determine the minimum limit of trace mercury measurement in atmosphere by the cold vapor atomic absorption method. This paper studies a new method of mercury detection using the common mercury lamp as sources which correct the background according to the transverse Zeeman effect. The resonance spectral line (253.65 nm) of the meccury lamp generates σ-, σ+, and π linear polarized light in the vertical direction of the magnetic field. This study obtains mercury absorbance of σ-, σ+, and π light in different magnetic field intensity by using ultra-high resolution spectrometer, then gets the minimum field intensity of the method. We discuss the existing possible interference caused by benzene with narrow-band absorption and acetone with broadband absorption under 1.78 T magnetic field intensity. Taking σ- and σ+ as background light, and π as absorption light, we quantify the saturated mercury vapor cell with different lengths. With the accurate background correction, the R value of absorption fitting curve can achieve 0.99. Results indicate that the method can accomplish the job of accurate background correction and can be applied to trace mercury measurement in atmosphere.

Analysis of heavy metals and inorganic element content in Stereospermum colais leaves

In the present study, the presence of heavy metals (Lead, Copper, Cadmium, Arsenic and Mercury) and inorganic elements (Sulphate, Fluoride, Chloride) were quantitatively estimated from the leaves of Stereospermum colais. Lead, Copper and Cadmium were analyzed using Atomic Absorption Spectrophotometry (AAS). Arsenic was estimated by colorimetric method. Mercury was estimated by cold vapour atomic absorption method. The qualitative analysis of inorganic elements was performed. Sulphate, fluoride and chloride were quantitatively estimated by turbidimetric, colorimetric and argentometric methods, respectively. The obtained results revealed that the content of heavy metals was within the permissible levels and hence the plant was safe to be utilized in herbal drug formulation.DOI: http://dx.doi.org/10.3329/icpj.v2i3.13583 International Current Pharmaceutical Journal, February 2013, 2(3): 63-66

RETRACTED: Serum hormone and biochemical activity as biomarkers of mercury toxicity in the yellowfin seabream Acanthopagrus latus

This study was undertaken in two separate environmental and experimental conditions. The environmental test was carried out at creeks in the Persian Gulf and the experimental test was undertaken in seawater re-circulatory tanks. Mercury concentrations were determined using a standard cold vapour atomic absorption method. Serum enzymes were determined with Diagnostics Infinity reagent kit. Serum glucose and total protein were measured photometrically. Serum hormones were assayed using diagnostic ELISA kits. Results of the present investigation indicated that the sub-acute and chronic mercury concentrations tested may cause several changes in the biochemical and hormone parameters of the studied fish and we can use these changes as biomarkers for mercury detection. The range of mercury concentrations found in the creek water and specially sediments along the Mahshahr coast was higher than the other marine environment. It was declared that between enzymatic indices serum acid phosphatase (ACP) amount and ACP activity, between hormonal indices testosterone, T3 and T3/T4 and between metabolite index total protein can be considered as suitable and effective biomarkers of mercury pollution in yellowfin seabream.

Thermodynamic and kinetic study of the single extraction of mercury from soil using sodium-thiosulfate

The use of sodium-thiosulfate (Na-thiosulfate) as a reagent for the extraction of mercury (Hg) from soil was investigated. High organic matter content in soil plays a major role in retaining metals. It has previously been reported that using the cold vapour atomic absorption method, powerful reagents such as EDTA, DTPA and cysteine could not release Hg from soil samples. The optimal conditions for using Na-thiosulfate to extract soil-Hg are presented here. Our results show that 50 ± 5% of total Hg was extracted from soil samples using 0.01 mol L −1 of the reagent without pH adjustment. Increasing the reagent concentration above this level showed no significant change in Hg extraction. From this extraction three fractions of Hg were obtained, the labile, slowly labile and un-extractable. We further applied the use of a kinetic extraction approach that has never been applied for Hg. We observed a correlation between the first two fractions and the quantity of organic matter content in soils. The labile fraction could be released by using any concentration of the reagent. However, the slowly labile fraction was dependent on time and increased concentrations of Na-thiosulfate. Furthermore, our results suggest that the labile and slowly labile fractions involve two different sites of reduced sulphur groups contained in soil organic matter and Hg levels present in the soil samples did not appear high enough to saturate all these high affinity sulphur sites. The capacity of Na-thiosulfate to reduce (Hg(II)) to (Hg(0)), was determined to be negligible. Our results further suggest the implication of iron (Fe(II)) for reducing Hg(II) to Hg(0). Here we have demonstrated that Na-thiosulfate is an effective reagent in the extraction of Hg from soil, with the particular characteristic of its ability to remove strongly bound Hg from sulphur groups contained in soil organic matter.

The study of Effective Factors in Mercury Removed from Aqueous Solutions Using Granular Activated Carbon

Introduction: Wastewaters of chemical, petrochemical, electrical, pharmaceutical and paper industries are the main sources of mercury and its compounds. Mercury is one of the toxic elements, so its removal from water and industrial wastewaters seems to be important and essential. The objective of this study was to investigate effective factors such as PH, contact time, absorbent dose, mixing rate and initial concentration in mercury removed by employing Granular Activated Carbon (GAC). Materials and Methods: In this study GAC was used as absorbent of the mercury. Mercury solution was prepared by mercury chloride. 136 samples were analyzed and the mixture of samples and activated carbon in 100 cc flasks were shaked. Then the samples filtered and the filtrates were tested to determine the mercury concentration by employing Cold Vapor Atomic Absorption Method at the wavelength of 253.7 nm. Results: Mercury removal increased at pH from 2 to 4 and optimum pH occurred in the range of 4-8. Increasing processing time to more than 10 min, had no significant effect on the absorption rate of mercury. Removal percentage increased with increasing weight of GAC but the amount of absorbed mercury ion per unit weight decreased from 2.216 mg to 0.0806 mg. conclusion: Increasing the amount of mercury at pH>4 was due to formation of predominant species of Hg(OH) 2 which retained in micro pores of GAC particles. The kinetic of mercury absorption by GAC was remarkably fast and increasing processing time to more than 10 min up to equilibrium absorption had no significant effect The results showed that the mercury removal had increased with increasing weight of GAC. This phenomenon happened as the result of increasing absorbent surface.

Blood mercury levels of dental students and dentists at a dental school.

To determine the blood mercury levels in dental students and clinical teaching staff in a dental school using amalgam as a restorative material. A dental school in Ege University, Turkey surveyed during one academic year. Cross-sectional study of groups of dental students (n=92) in years I to V, clinical teachers in restorative dentistry (n=16) and controls (n=14). Mercury concentration was estimated in venous blood samples using a cold vapour atomic absorption method at the commencement and end of the academic year. Daily air mercury levels were determined in clinical and teaching areas by measuring the darkening of palladium chloride discs using spectrophotometry. There were statistically significant increases (p<0.001) in plasma mercury concentration between measurements in all groups at the end of the academic year. Red cell mercury levels were also consistently elevated. Although the highest levels of mercury were recorded in persons working with amalgam, increased levels were also found in subjects working in the teaching classrooms but not with amalgam (controls and first year students). Increased mercury levels appeared to be due to background exposure from spillage of mercury and amalgam residues on floors. Increased mercury hygiene and regular control of working atmosphere should be implemented to prevent mercury exposure in the dental pre-clinical laboratory.

Mercury vapour exposure: a study of dental student

Objective To determine the blood mercury levels in dental students and clinical teaching staff in a dental school using amalgam as a restorative material. Setting A dental school in Ege University, Turkey surveyed during one academic year. Subjects and methods Cross-sectional study of groups of dental students (n=92) in years I to V, clinical teachers in restorative dentistry (n=16) and controls (n=14). Mercury concentration was estimated in venous blood samples using a cold vapour atomic absorption method at the commencement and end of the academic year. Daily air mercury levels were determined in clinical and teaching areas by measuring the darkening of palladium chloride discs using spectrophotometry. Results here were statistically significant increases (p<0.001) in plasma mercury concentration between measurements in all groups at the end of the academic year. Red cell mercury levels were also consistently elevated. Although the highest levels of mercury were recorded in persons working with amalgam, increased levels were also found in subjects working in the teaching classrooms but not with amalgam (controls and first year students). Conclusion Increased mercury levels appeared to be due to background exposure from spillage of mercury and amalgam residues on floors. Increased mercury hygiene and regular control of working atmosphere should be implemented to prevent mercury exposure in the dental pre-clinical laboratory.

A sequential injection cold-vapor atomic absorption method for the determination of total mercury.

A sequential injection (SI) method for the determination of mercury via cold vapor atomic absorption spectrophotometry is presented. The method differs from flow injection (FI) cold vapor methods for the determination of mercury because of the simplicity of the system required for the method: one pump, one valve, a gas-liquid separator, and an atomic absorption spectrophotometer equipped with a quartz cell. Under optimal conditions, the method has the following figures of merit: a linear calibration range of 1.0 to 20 microg L(-1); a detection limit of 0.46 microg L(-1); and a precision of 0.90% RSD (8 microg L(-1)). The procedure allows for a sampling rate of one injection per 80 s (excluding sample pretreatment). Results from the determination of mercury in water and fish specimens are also presented. The figures of merit of the method are compared to two other SI methods for the determination of mercury.

Distribution of mercury in lichens across St. Charles, St. James, and St. John Parishes, Louisiana

Concentrations of mercury in the lichens Ramalina stenospora and Parmotrema praesorediosum were determined using a Bacharach Model 50B analyzer system employing the Environmental Protection Agency (EPA) cold vapor atomic absorption method. Samples were collected from the limbs of live oak trees in a three-parish area in south-east Louisiana. The highest concentrations detected were above 0.8 ppm (μg/ml) and fell off rapidly with increasing distance from possible sources of trace metals. The spatial distribution of mercury concentrations correlated with predominant wind patterns for the region.

Chelating 2-mercaptobenzothiazole loaded resin. Application to the separation of inorganic and alkylmercury species for their atomic absorption spectrometry determination in natural waters

A new 2-mercaptobenzothiazole loaded Bio-Beads SM-7 resin has been prepared and its analytical properties were established. The sorbent was applied to the separation and preconcentration of inorganic and alkylmercury from natural waters. Optimum conditions of separation as pH, flow rate on column, volume of samples and desorbing agent were established. The cold vapour atomic absorption method determination of both forms of mercury after their successive reduction by tin(II) was used. The low limit of determination for this method was established as 10 ng l −1 for 1.0 l water sample. Accuracy and precision of the method was estimated by using test water standards and samples of natural water spiked with known amounts of mercury species.

Mercury uptake patterns of biota in a seasonally anoxic northern California Reservoir

Biotic uptake of mercury (Hg) in Davis Creek Reservoir, California increased dramatically in conjunction with the entrainment of anoxic hypolimnetic water into the mixed layer. This indicated a seasonal pulse increase of bioavailable Hg associated with thermal destratification. The effect was more pronounced in juvenile bass (70–200% seasonal increases in muscle Hg concentration), as compared to adults (15–25% increases), and was most distinct in zooplankton, which spiked to concentrations of 3–6 mg/kg, dry weight, immediately following fall destratification (130–270% seasonal increases over pre-fall levels). In addition to the general buildup of methyl Hg in the hypolimnion under anoxic conditions, a dense layer of photosynthetic anaerobic bacteria just beneath the thermocline is implicated as a potentially important seasonal source of methyl Hg to reservoir fish. Hg increases in juvenile and adult fish correspond to late summer and fall entrainment of upper hypolimnetic water, while zooplankton spike increases may be partially related to ingestion or adsorption of Hg-scavenging manganese oxides, which precipitate following full turnover. A simple and effective, syringe-based cold vapor atomic absorption method for total Hg is also described.

Cold Vapor Atomic Absorption determination of mercury by Flow Injection Analysis using a Teflon membrane phase separator coupled to the absorption cell

A Flow Injection Analysis (FIA) procedure for the determination of trace amounts of mercury by the Cold Vapor Atomic Absorption (CVAA) method is presented. In order to make efficient use of the FIA technique, a new flow cell was developed to permit a rapid separation of elemental mercury from the carrier solution. The design of this device is based on the permeability of Hg 0 in commercially available Teflon (PTFE) tape, which acts as a membrane phase separator. The calibration curve is linear up to 70 ng.ml −1 ( A = 0.005 + 0.008 Hg(ng.ml −1); r = 0.9996) using a 15-cm open cell approach, with a detection limit of 1.4 ng. ml −1 (0.66 ng of mercury), considering a signal to noise ratio of three. The standard deviation is s = ±0.004 absorbance units, calculated at a level of 50 ng.ml −1 of Hg 2+. The sampling rate was 110 samples per h.

The Measurement of the Solubility of Metallic Mercury in Hydrocarbons by Means of the Cold-vapor Atomic Absorption Method

Abstract The metallic mercury solubility in hydrocarbons (pentane, hexane, heptane, and octane) was determined in the temperature range from 5 to 40 °C by the cold-vapor atomic absorption method. The results, for pentane at 25 °C, were found to agree well with Kuntz’s result obtained by means of the ultraviolet absorption method, while those for hexane, heptane, and octane were found to agree well with Spencer’s results, which were obtained using a radioactivetracer technique in the above temperature range. The liquid-liquid distribution constant for metallic mercury between the above hydrocarbons and water was measured at 25 °C, and in each case was found to be equal to the ratio of the independent solubility in the hydrocarbon and in water.

Effect of sorption on mercury determination by the cold-vapor atomic-absorption method

Effect of sorption on mercury determination by the cold-vapor atomic-absorption method

Epidemiological Experience with the Magos' Reagents in the Determination of Different Forms of Mercury in Biological Samples by Flameless Atomic Absorption

Total mercury was determined by the introduction of CdCl/sub 2/ in the presence of SnCl/sub 2/ to break the mercury to carbon bond with subsequent reduction of Hg/sup 2 +/ to Hg/sup 0/ which is determined by a flameless atomic absorption method. Inorganic mercury is determined in the absence of CdCl/sub 2/, and the organic mercury is calculated by the difference between total and inorganic mercury. The preparation of samples of whole blood, hair, urine, tissue, fish, and sediment samples is described in detail. Results obtained by this cold vapor atomic absorption method are shown to be in good agreement with results obtained for mercury content of samples analyzed by gas chromatography, proton microprobe, and x-ray fluorescence.

Determination of mercury in fish from rivers and lakes in Hungary by atomic absorption technique

In 1975, in cooperation with 8 County Hygienic Stations, total mercury content in fish from rivers and lakes in Hungary was measured. The mercury content in fish muscle-tissue from 164 fish samples averaged 0.36 mg/kg. Average levels in different fish species ranged from 0.10 to 0.57 mg/kg. The amount of mercury in fish from rivers and lakes, with the exception of the Danube, was, in general, lower than the tolerance level (0.50 mg/kg) as adopted in many countries. Mercury levels in fish from Lake Balaton did not amount to more than 0.30 mg/kg. The circulating cold vapour atomic absorption method was used to determine the mercury content in the fish samples.