益智及其种植区土壤中汞含量研究

采用氢化物原子荧光法测定了益智种植区土壤与益智各部位中的痕量汞,比较了HNO3＋HF＋H2O2、HNO3＋HF、HNO3＋HClO43种混酸消解体系的消解效果。结果表明,HNO3＋HF＋H2O2为最佳消解体系;样品加标回收率为93．70％～102．25％;土壤及益智果实、根、茎、叶中汞含量分别为0．3583、0．1632、0．0950、0．0700、0．0747mg·kg^-1,土壤中汞在益智果实、根、茎、叶间的迁移率分别为45．55％、26．51％、19．52％、20．83％,土壤及益智各部位的汞含量均在国家规定标准以内。说明海南益智种植区地理环境良好,未受到汞污染。     

不同消解方式对土壤中锑的原子荧光法检测影响

氢化物发生-原子荧光光谱法是土壤环境中锑检测所广泛使用的方法．土壤的消解前处理分别采用王水微波消解（半消解）、混酸全消解（硝酸＋高氯酸＋氢氟酸）方式．研究结果表明王水微波消解对锑的检测效果较好,标准土壤9次测定值的相对标准偏差为3．6％,实际样品的回收率为96％-102％．而采用混酸全消解的方式测定值偏低,实际样品的回收率为78％～86％,而且精密度超过5％,这是由于在赶酸过程中样品易被蒸干而造成痕量锑元素的损失．     

微波消解-原子荧光光谱法测定服药动物排泄物中的微量汞

采用微波消解溶样技术和原子荧光光谱法，测定了服药(安宫牛黄九、朱砂、硫化汞)实验动物大众粪便排泄物中不同时间的汞合量，初步研究了汞的排泄情况，确定了微波消解样品的条件，优化了仪器的最佳工作参数。该法简便、快速、准确，汞合量在0—20ng／mL范围内线性良好，r＝0．9996，RSD＝2．8％，为安宫牛黄九的减毒机理、药效和毒性的科学评价提供了一定的依据。     

微波消解-氢化物发生原子荧光光谱法测定头发样品中的微量汞

对微波消解-氢化物发生原子荧光光谱法测定头发样品中微量汞的方法进行了研究。采用HNO3和H2O2作消解剂,在最佳微波消解条件和测定条件下,线性回归线方程为Y=259．7c 155.4,相关系数r=0.9996,检出限为0．01ng／mL,线性范围为0-20ng／mL。测定结果的相对标准偏差为0,4％～2．8％,回收率为94,0％-102．0％。     

微波消解一氢化物原子荧光光谱法测定罐头食品中锡

为建立微波消解-氢化物原子荧光光谱法测定罐头食品中锡含量的方法。样品在HNO3＋HC1或HN03＋HCl＋H2O2体系中经微波消解处理后,以硫脲-抗坏血酸混合液作预还原剂,用氢化物原子荧光光谱法测定罐头食品中锡。结果表明,在优化的条件下,锡质量浓度在0～100μg／L范围内线性关系良好,相关系数为0．9998,方法最低检出限为0．067mg／kg,加标回收率在99．7％～108．3％之间,方法变异系数为2．67％（n=6）。该法具有准确度高、精密度好、灵敏快速且安全环保等优点,适用于罐头食品中锡的测定。     

“新型高压湿法消解方法”在铅检测中的应用

在食品中和生物材料的微量元素检测中,应用新型高压湿法消解前处理方法,快速、高效地消解各类样品。综合各种因素,对普通食品、生物样品,最佳消解条件为120℃时,3h,样品质量（g）／浓HNO3量（mL）／H2O2（mL）为1：3：1。由回收率试验可知,铅的回收率在95．8％－104．5％,其准确度完全能够满足食品或生物材料中微量金融分析的要求。由于高压湿法消解比干法灰化方法具有快速、高效、准确度高,且消解温度低（低于150℃）,无污染,节省能源等优点,将该法引入食品和生物材料检测工作,可大大提高工作效率,而且可以提高检测准确度。     

高压消解-双道氢化物发生-原子荧光光谱法同时测定女贞属苦丁茶中砷与汞

采用HNO3/H2SO4常压预消解,HNO3/H2O2高压消解,硫脲-抗坏血酸溶液预还原等手段,建立了高压消解-双道氢化物发生-原子荧光光谱法同时测定女贞属苦丁茶中砷和汞含量的新方法。考察并优化了分析条件。该方法砷与汞的检出限分别是4.73×10-5 mg.L-1、8.7×10-6 mg.L-1;相对标准偏差(n=10)砷小于2.15%,汞小于3.47%。方法可应用于女贞属六种苦丁茶中砷和汞的测定。     

微波消解-氢化物发生原子荧光光谱法同时测定化肥中砷、汞含量

采用微波消解样品前处理手段以及双道原子荧光光度计,建立了微波消解一氢化物发生原子荧光光谱法同时测定化肥中砷、汞含量的方法。通过试验确定了样品前处理方法,对负高压、灯电流,载气、屏蔽气、原子化器高度、酸度等测试条件进行了优化。在优化的工作条件下,砷、汞含量分别在0-50ng／mL和0—1．0ng／mL范围内与荧光强度呈良好的线性关系,线性相关系数分别为0．9996,0．9996,检出限分别为0．085,0．008ng／mL,回收率分别为88．8％～107．4％,90．0％～120％,测定结果的相对标准偏差均小于7％（n=6）。     

Keggin型磷钼钒季铵盐催化氧化苯制苯酚反应研究

采用分步反应、分步酸化法制备了磷钼钒缺位型杂多酸,用（C4H9）4N^＋（以下简写为Bu4N^＋）阳离子取代杂多酸中H^＋作为反荷离子合成了杂多季铵盐（用于苯氧化制苯酚反应）．FT-IR分析反应前后催化剂结构的变化．以苯为原料,乙酸为溶剂,30％H2O2作氧化剂,系统考察了催化剂类型、催化剂用量、氧化剂用量、反应时间及温度对反应的影响．实验结果表明,56．4mmol苯在（Bu4N）5PMo10V2O40用量0．25mmol,30％H2O2用量10mL,溶剂乙酸10mL,70℃条件下回流反应6h,苯酚收率可达到27．9％．     

有机复习中的专题讲座

有机复习的基本任务是架设以CH4、CH3COOC2H5为代表物的“分条分块”体系和以“CH3CH3←CH2＝CH2←CH＝CH络”关系。同时,还必须针对高考热点,开辟若干专题进行深入的复习。一、燃烧问题专题印发下列问题师生共同讨论：1．两个通式烃类燃烧通式：CxHy＋（X＋y／4）O2→XCO2＋y／2H2O烃的衍生物燃烧通式：Cx＋HyOz＋（x＋y／4－Z／2）O2→XCO2＋y／2H2O2．四种量（1）体积变化量气态烃（或气态烃的混合物）CxHy与足量氧气混合点燃,然后恢复到原状况（水为蒸气）,则总体积变化量是烃体积的（y／4－1）倍。显然,当y＝4时…     

柱前衍生化高效液相色谱法测定朱砂中可溶性汞的含量

采用二乙基二硫代氨基甲酸钠柱前衍生化高效液相色谱法测定了朱砂在人工胃液中的可溶性汞含量;本法简便,灵敏,精确,可用于朱砂及含朱砂的中成药中可溶性汞的含量测定及质量检验.     

Atomic absorption spectrometric determination of mercury in soil standard reference material following microwave sample pretreatment

Several decomposition procedures and their influence on the determination of mercury by electrothermal (ET) and cold vapour (CV) atomic absorption spectrometry (AAS) have been studied. Soil samples were decomposed by microwave digestion in closed and open vessels as well as by digestion under reflux according to German standard. The use of different acids (HNO₃, HCl or aqua regia) was evaluated and compared in respect to their influence on the determination of mercury by ET AAS and CV AAS. The digestion solutions were analyzed by ET AAS with a palladium modifier and by CV AAS using SnCl₂ or NaBH₄, as reducing agents. The detection limits obtained with different procedures were also evaluated. For the soil containing 6.25 g/g of Hg the ET AAS measurements were possible. In the case of lower concentration of mercury the CV AAS determination following the microwave digestion procedure with HCl or aqua regia is recommended. The accuracy of the proposed procedure was confirmed by the determination of total mercury in SRM 2711 Montana Soil.On leave from: Institut für Analytische Chemie, Technische Universitat Wien, Getreidemarkt 9, A-1060 Wien, Austria     

朱砂中汞的生物可接受性及其吸收与排泄

研究了朱砂中汞的生物可接受性及其在体内的吸收与排泄.采用体外消化透析法测定了朱砂中汞的生物可接受性;计算了大鼠灌胃给予临床剂量(50mg/kg)朱砂后汞的药动学参数;测定了给予临床剂量的朱砂后大鼠粪样中汞的排泄量.结果表明,朱砂中汞的溶出率为0.011%,生物可接受率为0.003 3%.大鼠灌胃给予临床剂量的朱砂后,汞的药动学参数为:最高血药浓度(ρmax)为(6.3±1.3)μg/L,达峰时间(tmax)为(1.3±0.4)h,半衰期(t1/2)为(4.2±0.5)h,血药浓度-时间曲线下面积(AUC)为(54.7±8.7)μg.h.L-1.给予朱砂12h后汞在粪便中排泄量最大,96h后在粪样中仍可检测到少量汞.朱砂中汞的生物可接受性较低,在体内吸收少,滞留时间较长,排泄缓慢,长期服用可在体内蓄积,产生毒性.     

王水消解-冷原子吸收光谱法测定土壤中汞

为了寻求一种更加适宜测定土壤中汞含量的测试方法,将检出限低、精密度高的冷原子吸收光谱法与便捷、高效的王水水浴消解土壤处理方式相结合,建立了王水消解-冷原子吸收光谱法测定土壤中汞。通过测定方法的线性相关性、方法检出限、准确度、精密度、加标回收率,并与原子荧光光谱法进行对比实验来评价该方法的有效性。王水消解-冷原子吸收光谱法在汞质量浓度0.0～1.0μg/L范围内线性良好,相关系数可以达到0.999 9,方法检出限为0.000 75mg/kg,土壤标准样品测试的相对标准偏差为4.0%～10.7%,实际样品加标回收率分别为93%～104%。采用原子荧光光谱法进行对比测试,原子荧光光谱法的方法检出限为0.002 5 mg/kg,相对标准偏差为4.8%～13.5%,加标回收率为104%～107%。结果表明,对于王水水浴消解土壤的方法不仅适用于原子荧光光谱法测定汞含量,同样可以应用于冷原子吸收光谱法中。所建立的王水消解-冷原子吸收光谱法具有更低的检出限,更优的准确度和精密度,有利于提高土壤样品测试的工作效率,值得推广。     

王水消解-冷原子吸收光谱法测定土壤中汞

为了寻求一种更加适宜测定土壤中汞含量的测试方法,将检出限低、精密度高的冷原子吸收光谱法与便捷、高效的王水水浴消解土壤处理方式相结合,建立了王水消解-冷原子吸收光谱法测定土壤中汞。通过测定方法的线性相关性、方法检出限、准确度、精密度、加标回收率,并与原子荧光光谱法进行对比实验来评价该方法的有效性。王水消解-冷原子吸收光谱法在汞质量浓度0.0~1.0μg/L范围内线性良好,相关系数可以达到0.9999,方法检出限为0.00075 mg/kg,土壤标准样品测试的相对标准偏差为4.0%~10.7%,实际样品加标回收率分别为93%~104%。采用原子荧光光谱法进行对比测试,原子荧光光谱法的方法检出限为0.0025 mg/kg,相对标准偏差为4.8%~13.5%,加标回收率为104%~107%。结果表明,对于王水水浴消解土壤的方法不仅适用于原子荧光光谱法测定汞含量,同样可以应用于冷原子吸收光谱法中。所建立的王水消解-冷原子吸收光谱法具有更低的检出限,更优的准确度和精密度,有利于提高土壤样品测试的工作效率,值得推广。     

Extractability of HgS (cinnabar and metacinnabar) by hydrochloric acid

In this work we investigated the behaviour of pure HgS during extraction with dilute HCl to establish its extractability in 1 and 6 M HCl at the concentration level close to those occurring in natural sediments and soils. We found that neither cinnabar nor metacinnabar were soluble in 1 M HCl, whereas both were partially extracted by 6 M HCl. Metacinnabar precipitated in the laboratory was most prone to dissolution in 6 M HCl (up to 90%), followed by crystalline (commercial) metacinnabar (up to 70%) and cinnabar (up to 15%). Solubility of HgS in 6 M HCl was found to be dependent on its concentration, and an exponential relationship between quantity of HgS added to 20 mL of 6 M HCl (the range of 0.1-10 mg was used) and the solubility in 6 M HCl was established. For higher concentrations of HgS (10 mg in 20 mL of acid), a similarly low solubility of cinnabar was obtained as found in the literature. A study of dissolution kinetics of HgS in 6 M HCl indicated that it was a fairly slow process. Unexpected oxidation of HgS in water or 1 M HCl was found for extractions performed in Teflon vials previously used for the digestion of residual undissolved HgS by aqua regia. We presumed that the Teflon material could preserve some oxidising gases (presumably Cl(2)) developed during digestion with aqua regia which can then oxidise HgS during extraction with water or 1 M HCl. Regarding the extraction of Hg from natural sediments, we concluded that 6 M HCl could not be used to extract reactive Hg and predict bioavailability of mercury in sediments containing HgS and that experiments with model compounds should not be done at a concentration level several orders of magnitude higher than in natural samples.     

Quantification of mercury in soils and sediments – acid digestion versus pyrolysis

Mercury (Hg) pyrolysis techniques allow the differentation of Hg-binding forms in contaminated soils and sediments. However, data about reproducibility and accuracy of the results concerning quantification of single Hg-compounds and total Hg-concentrations are rare. Therefore the total mercury concentration of different contaminated soils and sediments determined by using a pyrolysis technique were compared to those obtained after aqua regia digestion and cold vapor atomic absorption spectroscopy Hg detection. Twenty replicates of four soil and two sediment samples containing different Hg-compounds were investigated by both methods. All samples were analyzed without any pretreatment. For most of the samples total Hg-concentrations determined by pyrolysis show lower values, and up to threefold higher relative standard deviation(s) (RSD) than those obtained after wet digestion. Soil samples containing specified Hg-compounds like metallic Hg (Hg⁰) or cinnabar (α-HgS) show by far higher RSD by means of both methods than samples containing only matrix-bound Hg-compounds. Single peak integration indicate that the distribution of Hg⁰ and cinnabar is usually heterogeneous resulting in RSD of up to 85%, whereas RSD of matrix-bound Hg-compounds were always distinctly lower. Besides the higher standard deviation the pyrolysis technique has been found to be reliable for screening contaminated soils and sediments due to the important additional information about occurring Hg-binding forms. Received: 13 February 1997 / Revised: 13 March 1997 / Accepted: 17 March 1997     

电感耦合等离子体质谱法测定地球化学样品中的银、砷、锑、铋

建立了王水分解样品,电感耦合等离子体质谱法测定地球化学样品中的银、砷、锑、铋的方法,采用王水-水浴分解试样,电感耦合等离子体质谱仪测定新疆和田策勒恰哈地球化学样品中的银、砷、锑、铋,确立了最佳的溶样时间、测定酸度、干扰元素的校正方法,结果令人满意。各元素的方法检出限为0.003 8~0.041g/g;相对标准偏差RSD(n=12)为0.52%~2.8%;方法灵敏度较好、简便、快速,且结果准确,适用于大批量地球化学样品的快速测定。     

微波消解-氢化物发生原子荧光法同时测定土壤中的砷汞

建立了微波消解-氢化物发生原子荧光法同时测定土壤中As、Hg的分析方法。用体积分数35%的王水作为消解溶剂,在设定的微波消解条件下,可以将土壤中的As、Hg提取完全,有效解决了消解液中剩余酸过多的问题。方法用体积分数5%的HCl作为反应介质,20 g/L NaBH4作为还原剂。通过测定国家标准参考物质和加标回收实验,对方法进行了验证。已用于土壤中As、Hg的测定。     

Influence of sample pre-treatment on the determination of trace silver and cadmium in geological and environmental samples by quadrupole inductively coupled plasma mass spectrometry

The suitability of three different digestion procedures has been evaluated with regard to the quantitative determination of trace amounts of silver and cadmium in geological and environmental samples. Procedure A: extraction with aqua regia in an open vessel system; Procedure B: extraction with aqua regia in a closed pressurized vessel system; Procedure C: digestion with HF + HNO₃ in a closed pressurized vessel system. It was found that procedure A represented an effective way of extracting analytes from different types of geological samples while the effect of extracting interfering metals is low. Because it is interference-free, poses a low risk of contamination and is time-saving, sample treatment procedure A was preferred. For this digestion procedure, a series of Chinese geological reference materials was determined by ICP-MS, the results of which were found to be in reasonable agreement with the certified values.