4,111 research outputs found

    Determination of Arsenic, Mercury and Barium in herbarium mount paper using dynamic ultrasound-assisted extraction prior to atomic fluorescence and absorption spectrometry

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    A dynamic ultrasound-assisted extraction method using Atomic Absorption and Atomic Flourescence spectrometers as detectors was developed to analyse mercury, arsenic and barium from herbarium mount paper originating from the herbarium collection of the National Museum of Wales. The variables influencing extraction were optimised by a multivariate approach. The optimal conditions were found to be 1% HNO3 extractant solution used at a flow rate of 1 mL min-1. The duty cycle and amplitude of the ultrasonic probe was found to be 50% in both cases with an ultrasound power of 400 W. The optimal distance between the probe and the top face of the extraction chamber was found to be 0 cm. Under these conditions the time required for complete extraction of the three analytes was 25 min. Cold vapour and hydride generation coupled to atomic fluorescence spectrometry was utilized to determine mercury and arsenic, respectively. The chemical and instrumental conditions were optimized to provide detection limits of 0.01ng g-1 and 1.25 ng g-1 for mercury and arsenic, respectively. Barium was determined by graphite-furnace atomic absorption spectrometry, with a detection limit of 25 ng g-1. By using 0.5 g of sample, the concentrations of the target analytes varied for the different types of paper and ranged between 0.4–2.55 ”g g-1 for Ba, 0.035–10.47 ”g g-1 for As and 0.0046–2.37 ”g g-1 for Hg

    A field deployable method for a rapid screening analysis of inorganic arsenic in seaweed

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    The authors thank the support for getting the seaweed samples from the projects funded under the Department of Agriculture, Food and the Marine’s Competitive research programmes in Ireland. Reference number 14 SF 860. The authors thank Corny Brombach for the graphical abstract.Peer reviewedPublisher PD

    Pollution of the aquatic biosphere by arsenic and other elements in the Taupo volcanic zone : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Biology at Massey University

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    An introduction to the Taupo Volcanic Zone and probable sources of polluting elements entering the aquatic environment is followed by a description of collection and treatment of samples used in this study. The construction of a hydride generation apparatus for use with an atomic absorption spectrophotometer for the determination of arsenic and other hydride forming elements is described. Flame emission, flame atomic absorption and inductively coupled plasma emission spectroscopy (I.C.P.-E.S.) were used for the determination of other elements. Determinations of arsenic and other elements were made on some geothermal waters of the area. It was found that these waters contribute large (relative to background levels) amounts of arsenic, boron and alkali metals to the aquatic environment. Some terrestrial vegetation surrounding hot pools at Lake Rotokawa and the Champagne Pool at Waiotapu was found to have high arsenic concentrations. Arsenic determinations made on the waters of the Waikato River and some lakes of the Taupo Volcanic Zone revealed that water from the Waikato River between Lake Aratiatia and Whakamaru as well as Lakes Rotokawa, Rotomahana and Rotoehu was above the World Health Organisation limit for arsenic in drinking water (0.05 ”g/mL) at the time of sampling. Arsenic accumulates in the sediments of the Waikato River and Lakes of the Taupo Volcanic Zone. The levels were variable, but characteristically around 100 ”g/g. Trout taken from the Waikato River and some lakes in the Taupo Volcanic Zone, had flesh arsenic concentrations of the same order of magnitude as the water from which they were taken. Trout from Lakes Rotorua, Rotoiti and Rotomahana contained average flesh mercury concentrations above the World Health Organisations limit for mercury in foodstuffs (0.5 ”g/g). There were positive correlations between weight, length and flesh mercury concentration. Freshwater mussels from Lakes Rotorua and Tarawera had arsenic concentrations above the World Health Organisations limit for arsenic in foodstuffs (2 ”g/g). Shellfish taken from the mouth of the Waikato river and from Raglan were below the World Health Organisation's limit for arsenic and mercury. Aquatic macrophytes from the Waikato River had arsenic concentrations many times greater than the water from which they were taken. Some samples of Ceratophyllum demersum had arsenic concentrations above 1000 ”g/g dry weight. Water cress from the Waikato River at Broadlands and Orakei Korako contained on average 400 ”g/g and 30 ”g/g arsenic respectively. An experiment was conducted on the uptake of arsenic by water cress. It was found that water cress does accumulate arsenic if placed in an arsenic solution

    Reliability of graphite furnace atomic absorption spectrometry as alternative method for trace analysis of arsenic in natural medicinal products

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    Purpose: To evaluate the comparative efficiency of graphite furnace atomic absorption spectrometry (GFAAS) and hydride generation atomic absorption spectrometry (HGAAS) for trace analysis of arsenic (As) in natural herbal products (NHPs).Method: Arsenic analysis in natural herbal products and standard reference material was conducted using atomic absorption spectrometry (AAS), namely, hydride generation ASSAAS (HGAAS) and graphite furnace (GFAAS). The samples were digested with HNO3–H2O2 in a ratio of 4:1 using microwave-assisted acid digestion. The methods were validated with the aid of the standard reference material 1515 Apple Leaves (SRM) from NISTResults: Mean recovery of three different samples of NHPs, using HGAAS and GFAAS, ranged from 89.3 - 91.4 %, and 91.7 - 93.0 %, respectively. The difference between the two methods was insignificant. A (P= 0.5), B (P=0.4) and C (P=0.88) Relative standard deviation (RSD) RSD, i.e., precision was 2.5 - 6.5 % and 2.3 - 6.7 % using HGAAS and GFAAS techniques, respectively. Recovery of arsenic in SRM was 98 and 102 % by GFAAS and HGAAS, respectively.Conclusion: GFAAS demonstrates acceptable levels of precision and accuracy. Both techniques possess comparable accuracy and repeatability. Thus, the two methods are recommended as an alternative approach for trace analysis of arsenic in natural herbal products.Keywords: Arsenic, Graphite furnace atomic absorption spectrometer (GFAAS), Hydride generation atomic absorption spectrometer (HGAAS), Natural herbal product

    Surface transects for arsenic speciation, antimony speciation, and alkaline phosphatase activity from R/V Knorr cruise KN204-01 in the Subtropical North Atlantic Ocean in 2011 (U.S. GEOTRACES NAT project)

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    Dataset: GT11 - As AP Surface TransectsSurface transects for arsenic speciation, antimony speciation, and alkaline phosphatase activity. Data for the concentrations of the dissolved (<0.4 ”m) arsenic species: total inorganic As (III+V), arsenite (AsIII), As(V), monomethyl As, dimethyl As, and the activity of the enzyme alkaline phosphatase (unfiltered). For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/3830NSF Division of Ocean Sciences (NSF OCE) OCE-0926423, NSF Division of Ocean Sciences (NSF OCE) OCE-092609

    Determination of Arsenic Content of Available Traditional Medicines in Malaysia using Hydride Generation Atomic Absorption Spectrometry

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    Purpose: To determine the content of arsenic (As) in some locally available traditional medicines in the East Coast region of Malaysia.Methods: The determination of As was conducted using hydride generation-atomic absorption spectrometry (HG-AAS). Sample preparation entailed mineral acid digestion using hydrochloric acid and nitric acid mixture in a ratio of 1:3. Sixty samples were collected from different locations including shops and open markets in East Coast region of Malaysia, namely, Pahang, Terengganu and Kelantan states. Most of these preparations were not registered with Malaysian drug authority.Results: Out of sixty traditional medicine samples, twenty six contained As in a concentration range of 0.2150 - 1.3254 ppm. As for the rest, they were below the limit of quantification (LOQ).Conclusion: Traditional medicine samples available in the east coast region of Malaysia contain levels of arsenic that can adversely affect health upon consumption.Keywords: Traditional medicine, Arsenic, Hydride Generation –Atomic Absorption Spectrometer HGAAS

    INTEGRATED GAS-LIQUID SEPARATOR-REACTOR FOR DETERMINATIONSn(lI) AT TRACE LEVELS IN SOLUTION Reaktor Separator Gas-Cair Terintegrasi untuk Penentuan Sn(lI) pada Level Renik dalam Larutan

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    ABSTRACT The determination of Sn(lI) ion at trace levels using integrated gas-liquid separator-reactor with hydride generation-quartz furnace atomic absorption spectrophotometer (HG-QFAAS) has been done. This modified gasliquid separator at various sizes was able to increase sensitivity in the determination of Sn(lI) in solution. The acid reagent mixing techniques, sample and reductant optimally occurs in a coil reaction before they are going to the gasliquid separators. The optimum conditions of parameter measurementin the determinationof Sn ion with HG method are influenced by type and concentration of acid, and the concentration of reductant has been evaluated. This optimum parameters can increase of analytical performance simultantly, which is shown by detection limit 3.74 J.lgCI for 100J.lLinjection volume (3.74 pg Sn). The accuracy of measurementshown by the % recovery of the Sn determination in natural water sample at > 95%, indicate this technique is good to be applied for tin analysis at picogram level. Keywords: Sn, hydride generation, gas-liquid reactor separator, QFAA

    Seasonal variation of arsenic concentrations in tubewells in west Bengal, India.

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    This study was conducted to monitor the changes in arsenic concentration during different seasons in a one-year period during 2002-2003 in selected tubewells in an arsenic-affected area in the district of South 24 Parganas in West Bengal, India, and to map the location of the wells. Seasonal variations in concentrations of arsenic in water were measured from 74 selected tubewells, ranging in depth from 40 to 500 feet. Water samples were collected from these wells during winter, summer, monsoon, and the following winter in 2002-2003. A global positioning system was used for locating the tubewells, and a geographic information system was used for mapping. There was evidence of seasonal variation in concentrations of arsenic in water (p=0.02) with the minimum average concentration occurring in the summer season (694 microg/L) and the maximum in the monsoon season (906 microg/L). From the winter of 2002 to the winter of 2003, arsenic concentrations increased, irrespective of the depth of the tubewells, from an average of 464 microg/L to 820 microg/L (p&lt;0.001). This extent of variation in arsenic concentration, if confirmed, has important implications for both epidemiological research and mitigation programmes

    Surface arsenic, antimony speciation, and alkaline phosphatase activity along with US GEOTRACES North Atlantic Transect from the R/V Knorr KN199-04, KN199-05 cruises in the subtropical N. Atlantic during 2010 (U.S. GEOTRACES NAT project)

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    Dataset: GT10 - As AP Surface TransectsData for the concentrations of the dissolved (<0.4 ”m) arsenic species: total inorganic As (III+V), arsenite (AsIII), arsenate (AsV), monomethyl As, and dimethyl As; and the activity of the enzyme alkaline phosphatase (unfiltered) on the surface transect. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/3520NSF Division of Ocean Sciences (NSF OCE) OCE-0926423, NSF Division of Ocean Sciences (NSF OCE) OCE-092609
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