土壤中锰的形态分析方法研究

采用Tessler的连续浸取程序，利用La-Zr涂履石墨管，石墨炉原子吸收光谱对土壤中不同形态锰的浸取与测定的条件进行了研究。经过对土样－3各形态的浸取液进行加标试验，其回收率在90%－110%，测定了一组土样，结果满意。     

涂层平台技术用于石墨炉原子吸收光谱法测定矿石中痕量金

关于改善石墨炉原子吸收光谱分析特性已有不少报导,其中以平台原子化技术和以难熔碳化物形式涂覆于石墨管表面的涂层技术具有成本低、简便易行的特点。本文则以氯氧酰锆涂覆处理平台(即涂层平台技术),不但解决了石墨管性能差异所引起的灵敏度差别,同时提高了灵敏度、稳定性,延长了石墨管使用寿命。本法用于矿石中痕量金的测定,灵敏度(特征浓度)为0.0004微克/毫升(1%吸收),变异系数小于10%。适用于地质样品中0.001～     

塞曼效应石墨炉原子吸收法测定骨肿瘤患者血清中铬

用镧盐涂覆石墨管,大幅度提高测定血清铬灵敏度,选用硝酸铵基体改进剂,消除干扰,方法简便快速,灵敏度和精密度高。     

石墨炉原子吸收法中热解涂层石墨管在无标准分析法测定环境样品中铬的应用

本文探讨了热解涂层石墨管测定铬的最佳实验条件,研究了各种酸和干扰物质的基体效应,提出用浓氨水为基体改进剂克服高氯酸的干扰。比较了各原子化温度时的理论和实验特征量。使热解涂层石墨管有可能用于无标准分析法测定各种环境样品中的铬。     

石墨炉原子吸收光谱法测定痕量钒的研究

本文采用石记原子吸收光谱对钒吸收线的特征，普通石墨管和热解石墨管中钒的原子化行为，灰化和原子化条件，基体效应等进行了研究，综合应用基体改进剂，光控升温和解石墨管技术，提高了电热原子吸收测定钒的灵敏度，特征质量为２４ｐｇ／０．００４４Ａ。     

石墨炉原子吸收法直接测定半导体材料-磷化铟中的微量铁

本文叙述用石墨炉原子吸收光谱法,直接测定半导体材料-磷化铟中微量铁的分析方法。样品用盐酸溶解。测定下限为0.3ppm,相对标准偏差为6％,加入回收率为98％。试验表明,用金属钽的盐溶液涂覆平度热解涂层石墨管,可使铁的吸光度增加2—3倍,测定的精密度也获得显著改善。在石墨炉的一般升温程序中,增加冷却步时,铁的吸光度提高15％左右。     

石墨管测试性能的研究及在无焰原子吸收法测定化探样品痕量银镉铍中的应用

本文详细研究了各种石墨管的测试性能和实际应用,对各种石墨管的记忆效应,灵敏度检测限,精密度和抗酸能力进行了比较,并研究了各种石墨管对银、镉、铍的灰化和原子化温度及在样品分析中的适应性。发现不同元素应选用不同厂家的石墨管是重要的,拟定了加入基体改进剂后的直接测定程序,应用于地球化学标样中痕量银、镉、铍的测定,其结果与可用值相符。本工作对其它元素测定和石墨管种类选择,也具有普遍的借鉴作用。     

对石墨管内锆涂层作用的初探

对石墨管表面进行难熔碳化物涂覆处理,是原子吸收分析中一种操作简单、成本低廉的石墨管改进技术。通常认为,管内的锆涂层可以减少试液及原子蒸气通过管壁的渗透、阻止某些待测元素与管壁直接接触生成难熔碳化物,并可能参与管内的化学反应。我们对涂锆与非涂锆管进行了电子显微形貌观察,并选择锑、锡在涂锆管与非涂锆管中进行了原子吸收测定的对比,以期对试验现象及锆涂层在石墨管内的主要作用做一些初步的探讨。     

石墨炉原子吸收光谱法测定高温合金中镓

研究了普通石墨管、平台石墨管和涂钼普通石墨管对镓的测定性能.得出涂钼普通石墨管对镓的测定灵敏度和重现性均好于其他石墨管.从而建立了一种更为满意的石墨炉原子吸收测定高温合金中镓的新方法.     

涂层石墨管的制备和应用——铝合金中锡的测定

本文研究了各种涂层石墨管的制备方法和应用效果,提出了用超声浸渍法处理石墨管,大大地缩短了处理时间,效果良好。用涂层管测定锡,灵敏度和精密度都得到提高,应用于铝合金中锡的测定,结果较满意。     

Surface and subsurface examination of graphite tubes after electrodeposition of noble metals for electrothermal atomic absorption spectrometry

The modification phenomena of noble metals (Pd, Ir, Rh) electrodeposited onto the inner surface of pyrolytic graphite (PG) coated furnaces were investigated mainly by electron microprobe analysis with energy dispersive X-ray emission detection. The conditions of electrodeposition were optimized in order to achieve the best analytical performance of atomic absorption measurements. Investigations concerning the distribution of noble metals on the tube surface and in-depth were performed at different stages of the tube history. It was found that the noble metals used for the modification do not form a compact layer on the surface but penetrate into the pyrolytic graphite structure already at the deposition step. When two metals were deposited together, both penetrated into the graphite structure. The degree of penetration of the pyrolytic graphite at high temperature differs for various metals. It was also demonstrated that electrodeposited noble metals remain in sub-surface domains of the graphite for hundreds of atomization cycles, which means that they can be used as permanent modifiers.     

不同表面石墨管测定比较及采用WPGT直接测定水系沉积物及煤飞灰中的钇

本文采用自制的钨金属表面石墨管(WPGT)测钇,并与其它石墨管进行了比较。WPGT测钇灵敏度高,为PGT的340倍,重现性好,抗干扰能力强,可用于水系沉积物等样品中钇的直接测定。     

石墨炉原子吸收法测定钒的研究

本文比较了在标准石墨管,热解涂层和全热解石墨管中钒的吸收信号形状。用全热解石墨管和EDTA铵盐作基体改进剂,直接测定水系沉积物中痕量钒。方法的特征量为61pg/0.0044A。     

Comparison of uncoated, pyro-coated and totally pyrolytic graphite tubes for the HGA-500 electrothermal atomiser

The analytical performance of three uncoated electrographite tubes, three pyro-coated electrographite tubes, one tantalum carbide (TaC) coated electrographite tube, and three totally pyrolytic graphite (TPG) tubes has been evaluated and compared. A test programme was devised to determine the useful operational lifetime of each tube, and assess the influence of tube age on the sensitivity of lead, manganese and vanadium measurements by atomic absorption spectrometry. The TPG tubes were found to be more durable than the other types studied, but the lifetime advantage depended on the thickness of the pyrolytic graphite. The best TPG tube, of 720 μm wall-thickness, lasted 2.5 times longer than the pyro-coated tubes, and 5 times longer than the uncoated electrographite tubes.The TPG tubes gave slightly poorer AAS sensitivity for lead, equivalent sensitivity for manganese, and 4 times better sensitivity for vanadium than the pyro-coated electrographite tubes. Also, with TPG, signal magnitude was more consistent throughout the lifetime of a tube. For each of the test elements studied, poorest sensitivity was encountered with the TaC-coated electrographite tube.     

Determination of vanadium in water by electrothermal atomisation atomic absorption spectrometry after extraction with 8-hydroxyquinoline in isobutyl methyl ketone

A sensitive method for the determination of vanadium in water by electrothermal atomisation atomic absorption spectrometry (ETAAS) is described. The vanadium is chelated with 8-hydroxyquinoline in isobutyl methyl ketone and determined by ETAAS after pre-heating the pyrolytic graphite coated graphite tube of a graphite furnace atomiser before injection. The effects of the pH and amount of reagent required for the extraction were studied. The precision, accuracy and interferences of the method were also investigated. The proposed method allows concentrations of vanadium of 0.16 microgram l-1 to be detected.     

Concentration conditions of formation of electrically conducting coatings from colloid-graphite dispersions

Concentration conditions under which electrically conducting graphite coatings can be formed on cardboard and polymeric dielectric substrates by deposition of graphite particles from colloid graphite dispersions were studied. It was found how the surface resistance of the samples varies, in the dc mode and in the microwave range, with the concentration and time conditions of formation of electrically conducting coatings. The transmittance and reflectance to microwave electromagnetic radiation were measured for samples coated with particles of colloid graphite from suspensions with various particle sizes.     

Glassy carbon tubes for electrothermal atomic absorption spectrometry

Summary The use of glassy carbon as a tube material in electrothermal atomic absorption spectrometry requires modifications to the power supply if temperatures and heating rates comparable to those for graphite tubes are to be obtained. Glassy carbon tubes frequently have a longer lifetime than pyrolytic graphite coated tubes made of polycrystalline electrographite. Peak height sensitivity for glassy carbon is better by a factor of two for some volatile elements, but up to a factor of five inferior for less volatile elements than that for pyrolytic graphite coated tubes. Peak area sensitivity is generally inferior by about a factor of two. Sample volume is limited to 5–10 l because of the smooth surface.From the signal shape it can be deduced that adsorption of analyte atoms at the tube wall plays an important role in glassy carbon, and is responsible at least in part for the lower sensitivity. Non-spectral interferences can be less pronounced in glassy carbon tubes for those interferents which interact with graphite tube surfaces. Glassy carbon is, however, no alternative to pyrolytic graphite coated tubes.

---

Glasartiger Kohlenstoff als Rohrmaterial für elektrothermische Atomabsorptionsspektrometrie

     

Preatomization behaviour of Se(-II), Se(IV), and Se(VI) in the graphite furnace without and with matrix modifiers

Summary Using ⁷⁵Se as a radiotracer, the preatomization behaviour of selenium in the graphite furnace was studied. The selenium forms investigated included Se(-II)-methionine, selenite, and selenate in a 0.2% HNO₃ solution, and in a 0.2% HNO₃ solution containing 1% NaCl. The effect of nickel nitrate and of the mixture of palladium/magnesium nitrates as matrix modifiers and of boron nitride coating of the graphite tube on the behaviour of selenium was investigated. The best stabilization effect for all oxidation states of selenium in the conventional graphite tube was achieved by using the mixture Pd/Mg. A considerable degree of modifier-free stabilization of selenuium could be achieved in boron nitride coated tubes. After the conversion of Se(IV) to a volatile piaselenol, a quantitative preatomization separation of Se(IV) from Se(VI) in the boron nitride coated tube was possible. However problems with these newtype tubes still to be solved include the need to increase the thermal stability of the coating.     

Electrothermal atomic absorption spectrometry of silicon vaporized from different surfaces

The dependence of silicon absorbance on inert gas flow rate, ashing temperature and the amount injected was studied for uncoated, pyrolytically coated and tantalum carbide-coated graphite tubes. The reasons for the anomalous curvature of the calibration graphs and other unusual phenomena are discussed. Most sensitive results for silicon were obtained by isothermal atomization from a tantalum-treated tube and platform.     

涂钨石墨管石墨炉原子吸收光谱法测定人参中锗

石墨炉原子吸收法测定锗的问题主要是样品原子化前会形成易挥发的GeO,影响分析灵敏度。有关测锗的报道见文献。本工作应用CCl_4萃取和水反萃取,涂钨石墨管石墨炉原子吸收测定人参中锗,获得满意的结果。