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颗粒中空气中HG标准分析操作步骤EPA

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  • 第1楼2004/08/04

    我看不懂你的题目意思??????

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  • 第3楼2004/08/05

    就是在空气中的汞VAPOR翻译成空气不准确。
    以及在颗粒物中的汞
    取样及分析方法,
    用的是国外的原子荧光。
    Standard Operating Procedure for Analysis of Particulate Phase Mercury
    Standard Operating Procedure for Analysis of Vapor Phase Mercury

    仪器
    Cold Vapor Atomic Florescence Detector

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  • 第6楼2004/08/06

    Standard Operating Procedure for Analysis of Particulate Phase Mercury
    June 1, 1994
    Version 2.0

    Standard Operating Procedure for Analysis of Particulate Phase Mercury
    1.0 Introduction/Overview
    The objective of the Lake Michigan Loading Study is to assess the contribution of atmospheric
    deposition to the concentration of mercury and other toxic trace species found in Lake Michigan.
    The atmosphere has been implicated as one of the dominant sources of mercury and trace elements
    to bodies of water and it is clear from investigations in remote regions of the globe that long range
    transport of mercury and other toxics from source regions is occurring. By quantifying the wet
    deposition and ambient concentrations of mercury it will be possible to determine the relative
    importance of precipitation and dry deposition in accounting for the atmospheric loading of
    mercury to Lake Michigan. In addition, investigating other ambient trace species will aid in the
    identification of significant mercury sources.
    Particle-phase mercury, Hg(p), generally represents a small but significant fraction of total
    atmospheric mercury. Recent advances in analytical chemistry have made quantification of the
    extremely low levels of Hg(p) possible, however, tremendous care must be exercised in all phases
    of sample handling and analysis. This protocol describes analysis of ‘acid-extractable’ total
    mercury from atmospheric particulate samples.
    2.0 Sample Analysis
    2.1 Summary
    The technique described by this protocol is designed for use with glass-fiber or quartz fiber filter
    media. When used in conjunction with an open-faced filter pack, these media demonstrate a low
    pressure drop and have a very low background level of Hg with proper pretreatment. Sample
    filters are stored at -40EC before analysis to prevent volatilization of the collected Hg(p).
    Particulate mercury is extracted into a 1.6 M nitric acid solution utilizing a microwave digestion
    technique. The mercury forms are then oxidized with bromine monochloride, to Hg2+. Oxidized
    mercury forms are subsequently reduced to Hg0 with stannous chloride (SnCl2). In this volatile
    form, the metal is purged from solution using an Hg-free nitrogen stream and collected on a goldcoated
    bead trap. A mercury-free pretreated soda lime trap is utilized in the purge system to
    capture acid gases that may damage the gold-coated bead trap. Quantification is accomplished
    using a dual amalgamation technique followed by cold vapor atomic fluorescence spectroscopy
    (CVAFS).
    All analytical procedures for determination of particulate phase mercury are carried out in a class
    100 laminar flow exhaust hood inside a Class 100 Clean Room. Nitrogen utilized for purging is
    99.998% pure and is stripped of any mercury using a gold coated trap before use in the purge
    system. Clean room gloves are worn at all times and all labware with which the samples and
    reagents comes into contact is cleaned weekly using the acid cleaning procedure described in
    Standard Operating Procedure for Sampling of Particulate Phase Mercury, Section 2.1.
    SOP for Analysis of Particulate Phase Mercury Volume 2, Chapter 2
    2-434
    2.2 Reagents and Materials
    All reagent lot numbers, preparation dates and procedures are recorded for each new batch of
    reagent used. A reagent blank is obtained after each new batch of reagent has been prepared.
    Bromine monochloride (BrCl), stannous chloride (SnCl2) and hydroxylamine hydrochloride
    (NH2OHCHCl) are prepared fresh monthly.
    Solid reagents (potassium bromide, potassium bromate, hydroxylamine hydrochloride and stannous
    chloride) are stored in the clean room in a desiccator containing silica gel and an open bed of
    activated charcoal. The caps of all reagent bottles are Teflon taped to reduce entry of vapor phase
    compounds. Even with these precautions, reagents will nevertheless absorb mercury over time and
    must be replaced. All reagents are made in the clean room, except the working standard solution.
    2.2.1 Hydrochloric Acid
    EM Science Suprapur hydrochloric acid is used to prepare BrCl and SnCl2. This acid
    characteristically has a very low blank value (20 pg/mL).
    2.2.2 Bromine Monochloride
    Bromine monochloride is prepared in a class 100 laminar flow exhaust hood by adding
    11.0 mg KBr per mL of HCl while the solution is stirred using an acid-cleaned Tefloncoated
    magnestir. When the KBr is dissolved, 15.0 mg KBrO3 per mL of HCl is added
    slowly and the solution is allowed to continue stirring. This process produces chlorine and
    bromine gas and must be performed slowly in a functioning exhaust hood. After addition
    of the salts the solution is a deep yellow color. If there is no color (or very faint) then the
    BrCl has been substantially reduced and will not have enough oxidizing power for use. In
    this case, the solution is remade. Bromine monochloride is stored at room temperature in
    the clean room. Fresh bromine monochloride is be prepared monthly or as needed.
    2.2.3 Hydroxylamine Hydrochloride
    30 grams of NH2OHCHCl is dissolved in MQ-water to make 100 mL in an acid-cleaned
    100 mL volumetric flask. This solution is purified by adding 0.5 mL of SnCl2 and purging
    overnight with Hg-free N2. The solution is stored in an acid-cleaned, dark Teflon bottle in
    the refrigerator. Fresh hydroxylamine solution is prepared every month or as needed.
    2.2.4 Stannous Chloride
    20.0 gm of SnCl2CH2O is placed into an acid-cleaned 100 mL volumetric flask. Working
    in a fume hood, 10 mL of concentrated HCl is added and the solution is then brought to
    100 mL with Milli-Q water. The solution is stored in an acid-cleaned, dark Teflon bottle
    in the refrigerator. Fresh stannous chloride is prepared every month or as needed.
    Volume 2, Chapter 2 SOP for Analysis of Particulate Phase Mercury
    2-435
    2.2.5 Milli-Q Water
    Deionized water, with a resistivity of 18.2 MÙ/cm, is prepared using a Milli-Q system
    from a pre-purified (reverse osmosis) water source. Milli-Q water is used for reagent
    preparation.
    2.2.6 Soda Lime Traps
    High purity grade soda lime (EM Science) is utilized in an acid-cleaned glass tube with
    glass wool endplugs and Teflon connectors. After packing, this trap is conditioned by
    purging a 0.5 M HCl solution through the trap for 30 minutes. The soda lime trap is
    changed after analysis of 30 samples.
    2.2.7 Preparation of Working Standard Solution
    100 µL of the stock Hg solution (1 mg/mL in nitric acid) is pipetted into a 1 L volumetric
    flask. 5 mL of concentrated BrCl is added and the flask is brought up to volume with
    MQ-water and thoroughly mixed. This is the Secondary Standard solution (100 ng
    Hg/mL). Replace this solution as needed (it is stable for at least one year).
    The Working Standard (2 ng Hg/mL) is prepared from the Secondary Standard solution by
    placing 2 mL of Secondary Standard into a 100 mL volumetric flask, adding 1 mL of BrCl
    and bringing the solution to volume with MQ. The Working Standard is replaced monthly.
    2.2.8 Nitric Acid Extraction Solution.
    The extraction solution is a 10% dilution of concentrated nitric acid (1.6M). A 1000 mL
    volumetric flask is filled with about

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  • 第7楼2004/08/06

    那两个连接就是文件。看英文我也有点

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  • 第8楼2004/08/06

    我试试看能不能看明白

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  • 第9楼2004/08/08

    我也是偶然才发现着两片文章的,居然和EPA有关系就发出来了。

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