离子色谱法同时测定脱硫海水中的SO_4~(2-)和SO_3~(2-)

采用离子交换色谱法同时定量分析脱硫海水中SO_4~(2-)和SO_3~(2-)。0.01 mol/L EDTA和0.10×10~(-3) mol/L NaOH混合溶液用于除去海水样品中Ca~(2+)、Mg~(2+)干扰,加入0.5%的甲醛溶液防止SO_3~(2-)氧化为SO_4~(2-)。实验采用DINOEX AS-9HC阴离子交换柱作分离柱,以9.00×10~(-3) mol/L Na_2CO_3溶液为淋洗液,电导检测器检测。方法线性范围为5.00~100.00 mg/L,加标回收率为97.85%~103.99%,相对标准偏差(RSD)为0.20%~2.07%。SO_3~(2-)的检出限为0.03mg/L,SO_4~(2-)的检出限为0.04mg/L。结果表明,本方法可以有效消除海水中Ca~(2+)、Mg~(2+)对低浓度SO_3~(2-)、SO_4~(2-)测定的干扰,可同时实现海水脱硫体系中SO_3~(2-)、SO_4~(2-)的定量分析。     

离子色谱法测定土壤中氯离子、硫酸根离子、硝酸根离子

建立离子色谱法测定土壤中Cl~–,SO_4~(2–),NO_3~–3种阴离子的含量。淋洗液为30 mmol/L KOH溶液,等浓度淋洗,流速为1.0 mL/min。Cl~–,SO_4~(2–),NO_3~–的线性范围均为0~20 mg/L,线性相关系数均大于0.999 9,检出限为0.051~0.082 mg/L,混合标准溶液测定结果的相对标准偏差为0.31~0.38%(n=10)。对土壤样品进行重复测定,3种离子测定结果的相对标准偏差均小于3%(n=7),加标回收率在95.0%~104.5%之间。该方法测定结果准确,操作简单、快速,适用于土遗址中Cl~–,SO_4~(2–),NO_3~–的测定。     

流动注射化学发光法测定呋塞米

在酸性条件下呋塞米对Ce(Ⅳ)-Na_2SO_3弱化学发光体系具有很强的增敏作用,据此建立了流动注射化学发光法测定呋塞米的新方法.该法测定呋塞米的线性范围为0.01～1.0 mg/L,检出限为4×10~(-3)mg/L(3σ),RSD为2.2%(n=11,ρ=0.2mg/L),回收率为95%～105%.该法已应用于片剂和针剂中呋塞米含量的测定.     

稳定剂对IC直接检测亚硫酸盐的影响研究

开发了以次磷酸钠为抗氧化剂的亚硫酸根样品预处理方式,与用甲醛稳定SO_3~(2-)相比,二者在前80小时内稳定效果处于同一水平,且SO_3~(2-)保存度皆在90%以上;90 h后甲醛稳定效果下降明显,而次磷酸钠稳定效果下降缓慢,水平占优。最终建立以次磷酸钠为前处理稳定剂的亚硫酸根样品离子色谱检测方法。色谱柱为盛瀚SH-AC-18,淋洗液为3.6mM Na_2CO_3+4.5mM NaHCO_3,流速1 mL·min~(-1),进样量25μL。亚硫酸根在0～12 mg·L~(-1)线性关系良好,相关系数0.999,检出限(S/N=3)0.024 mg·L~(-1)。在土壤浸出液中添加0.056、0.125、2.000 mg·g~(-1)三种水平的标准样品,其加标回收率为89%～105%,平行测试的相对标准偏差小于0.25%,精密度和准确度良好,符合标准要求。     

离子色谱法测定柠檬酸、柠檬酸钠中的F~-、Cl~-、SO_4~(2-)、C_2O_4~(2-)等

利用离子色谱仪,对柠檬酸、柠檬酸钠中的痕量F~-、Cl~-、SO_4~(2-)、C_2O_4~(2-)等进行测定,采用DIONEX ION PAC ASll-HC分离柱,以电导检测器检测,对淋洗分离条件进行了试验。选择NaOH作淋洗液,0.025～0.050mol/L NaOH做梯度淋洗,可使F~-、Cl~-、SO_4~(2-)、C_2O_4~(2-)等很好地分离,其中Cl~-在0.01～200mg/L,F~-在0.05～200mg/L,SO_4~(2-)在0.05～200mg/L,C~2O_4~(2-)在0.1～200mg/L范围内,浓度和响应值有良好的线性关系,检出限分别为F~-0.01mg/L、Cl~-0.01mg/L、SO_4~(2-)0.03mg/L、C_2O_4~(2-)0.03mg/L,回收率为90％～110％。该方法无需前处理,无基体干扰,可用于柠檬酸、柠檬酸钠中F~-、Cl~-、SO_4~(2-)、C_2O_4~(2-)的测定。     

离子色谱法测定石墨及其制品中的F~-和SO_4~(2-)

建立了离子色谱法测定石墨及其制品中F~-和SO_4~(2-)的检验方法。用乙酸钠灼烧样品,水微沸提取,过滤定容,过滤膜后用离子色谱对溶液中的F~-和SO_4~(2-)含量进行测定。选用3.6 mmol/L Na_2CO_3溶液为淋洗液,流量为0.7 mL/min,渗析时间为8 min,转移时间为30 s。F~-和SO_4~(2-)平均加标回收率分别为92.4%,105.2%;测定结果的相对标准偏差分别为1.42%,3.89%(n=8)。该方法稳定,操作简便,准确度高,分析速度快,适用于石墨及其制品中F~-及SO_4~(2-)的测定。     

离子色谱法测定核电站一回路冷却剂中痕量F~-,Cl~-和SO_4~(2-)

建立离子色谱法测定核电站一回路冷却剂中痕量氟离子F~-,氯离子Cl~-,硫酸根离子SO_4~(2-)的方法。采用80 mmol/L硼酸溶液配合氢氧化钾淋洗液发生器在线生成淋洗液,梯度洗脱,淋洗液流量为1.2 mL/min,在选定的分析条件下,NO_2~-,NO_3~-,PO_4~(3-)和CO_3~(2-)不干扰F~-,Cl~-,SO_4~(2-)的测定。F~-,Cl~-,SO_4~(2-)的质量浓度与其色谱峰面积呈良好的线性关系,线性相关系数分别为0.999 8,0.999 5,0.999 7,线性范围分别为0.85~30.0,2.65~30.0,2.00~30.0μg/L。F~-,Cl~-,SO_4~(2-)测定结果的相对标准偏差分别为0.56%~1.58%,0.85%~3.62%,1.21%~4.60%(n=7)。F~-,Cl~-,SO_4~(2-)的加标回收率分别为98%~104%,98%~108%,93%~108%。该方法快速、准确,满足核电站一回路冷却剂中痕量F~-,Cl~-,SO_4~(2-)的检测要求。     

离子色谱法测定土壤中的3种阴离子

采用离子色谱法测定土壤中Cl~-、SO_4~(2-)和NO_3~-的含量。10.000 0g样品加入超纯水100mL,振荡2h,超声60min,离心分离,取上清液,依次经0.45,0.22μm滤膜过滤。滤液中的3种阴离子在Dionex IonPac TM AS18阴离子分离柱上分离,流动相为22 mmol·L~(-1) KOH溶液,采用电导检测器。Cl~-、SO_4~(2-)和NO_3~-的线性范围均为1.00~9.00mg·L~(-1),检出限(3s)分别为0.006,0.006,0.003mg·L~(-1)。3种阴离子的加标回收率在94.0%~96.0%之间,测定值的相对标准偏差(n=10)小于2.0%。     

离子色谱法测定硝酸钠晶体中微量亚硝酸根的方法研究

为保持大尺寸硝酸钠单晶的优良性能,要求控制其微量杂质NO_2~-的含量在极低的浓度水平。因此亟需提供具有高实用性和强操作性的NO_2~-的测定方法。研究并提出了梯度淋洗-离子色谱法(A法)和阀切换-离子色谱法(B法)两种分离模式。取样品0.200 0g溶于水中,定容至100.0mL,经0.22μm滤膜过滤,取滤液进行离子色谱分析。梯度淋洗中,在9 min以内用8mmol·L~(-1) KOH溶液将NO_2~-从AS11-HC阴离子交换柱上洗脱,并用电导检测。随后用30mmol·L~(-1) KOH溶液将交换柱上由样品而来的大量NO_3~-在较短时间内洗脱,从而避免其对下一样品分析的干扰。在阀切换中,利用仪器的六通阀与加装的十通阀之间的切换实现NO_2~-与其基体的高浓度NO_3~-之间的分离。方法采用峰面积积分方式计算测试结果。上述两种方法的线性范围均在0.10～2.00mg·L~(-1)之间,检出限(3S/N)为8×10-4%(A法)和5×10-4%(B法)。另取同一样品分别按两种方法进行6次平行测定,测定值的相对标准偏差(n=6)依次为4.2%,3.2%。另分别在6份样品的基础上加入NO_2~-标准溶液,按上述两种方法操作进行回收试验,测得回收率分别为92.5%～108%(A法)和95.5%～104%(B法),结果表明两种方法各有优缺点。     

比色法测定气田水中SO_4~(2-)

测定SO_4~(2-)的方法有硫酸钡重量法、离子色谱法、比浊法、容量法.重量法测定常规水中SO_4~2准确、可靠,但该标准方法适用范围为SO_4~(2-)含量>40mg·L~(-1):离子色谱法可用于低含量SO_4~2分析,且准确、可靠,但由于该仪器本身条件的限制,对于现场SO_4~(2-)的监测无法进行,且费用高,操作不便;目视比浊法虽然简单、快速,但由于人为因素误差太大,准确度低.为了配合矿区在威远气田进行二造系-震旦系混合气田水防垢试验,达到快速、准确,现场监测SO_4~(2-)含量(防垢试验要求SO_4~(2-)<50mg·L~(-1)),采用硫酸钡比浊法.在酸性介质中,当有保护胶体(明胶)存在时,水中的SO_4~(2-)与Ba~(2 )生成细微的硫酸钡晶体悬浮在溶液中,使水溶液浑浊.在一定条件下,其浑浊度与水样中的SO_4~(2-)含量成正比.在660nm波长下用分光光计测量硫酸钡悬浮体的吸光度.该法的检测范围为5～35mg·L~(-1),可适用于现场监测SO_4~(2-),也可用于室内分析.     

离子色谱法同时测定土壤中Cl-、SO42-和 NO3-

利用离子色谱法同时测定土壤中的Cl^-、SO4^2-、NO3^-三种无机阴离子。采用30 mmol/L KOH淋洗液在1.2 mL/min流速下对Cl^-、SO4^2-、NO3^-三种无机阴离子进行分离测定,混合标准溶液的相对标准偏差为0.16%~0.84%,三种阴离子的线性范围都在0~150 mg/L,线性相关系数均大于0.999。三种阴离子的检出限分别是0.062、0.096和0.064 mg/L。对四种国家标准物质的测定结果表明(n=9),测定值与标准值一致,相对标准偏差(RSD)<3%,三种阴离子的加标回收率为95.6%~109%。采用离子色谱法测定土壤中的Cl^-、SO4^2-、NO3^-三种无机阴离子,方法简便、快捷、无污染,对人体无任何伤害,真正实现了绿色化学的分析要求。在6 min以内完成分析,适合大批量土壤水溶盐阴离子的测定。     

离子色谱法测定烟气脱硫海水中的亚硫酸根离子

建立了燃煤电厂烟气脱硫海水中亚硫酸根(SO2~3)的离子色谱-脉冲安培检测方法。色谱柱为IonPac AS14A阴离子交换柱,流动相为14 mmol/L NaOH-12 mmol/L Na2CO3溶液(pH 11.7),流速1.2 mL/min,脉冲安培法检测。因SO2~3易被氧化,故在采样时加入甲醛作为保护剂,使之稳定存在。在测定海水样品前,用NaOH溶液(pH 12.0)沉淀海水中的Mg2+,以避免其在pH较高的流动相中生成沉淀堵塞色谱柱。采用该方法检测SO2~3的线性范围为0～100 mg/L,平均回收率为116.8%,检出限为0.05 mg/L;对7.5,25.0和75.0 mg/L的海水基底加标溶液分别进行9次平行测定,其相对标准偏差(RSD)分别为2.1%,3.1%和4.0%。该方法具有快速、灵敏、选择性好等特点,用于烟气脱硫的海水中SO2~3的检测,可得到令人满意的结果。     

Flue Gas Desulfurization by Dielectric Barrier Discharge

There are many problems with flue gas desulfurization by traditional gas ionization discharge, including the large size of the plasma source, high energy consumption, and the need for a traditional desulfurization method. This paper introduces oxidization of SO₂ to sulfuric acid (H₂SO₄) in a duct by reactive oxygen species (O₂ ⁺, O₃) produced by strong ionization dielectric barrier discharge. The entire plasma reaction process is completed within the duct without the use of absorbents, catalysts, or large plasma source. The reactive oxygen species O₂ ⁺ reacts with gaseous H₂O in the flue gas to generate ·OH radicals, which can oxidize trace amounts of SO₂ in large volumes of the flue gas to produce H₂SO₄. Sulfuric acid is also produced by O₃ oxidation of SO₂ to SO₃, and SO₃ reacting with gaseous H₂O in the flue gas. Experimental results showed that with a gas temperature of 22 °C and reactive oxygen species injection rate of 0.84 mg/L, the SO₂ removal rate was 81.4 %, and the SO₄ ^2? concentration in the recovered liquid H₂SO₄ reached 53.8 g/L.     

Continuous flow analysis: Photometric determination of Cr(III) with chrome Azurol S using microwave treatment

The effect of microwave and ultraviolet radiation and ultrasonic treatment on the reaction of chromium(III) with Chrome Azurol S, Arsenazo I, Alizarin, and Thoron was studied in the batch and flow modes. It was found that the reaction of chromium with the above photometric reagents is most efficiently activated by microwave radiation of the power 500-200 Wt. The best analytical properties were found for Chrome Azurol S. A flow system was proposed for the photometric determination of chromium(III) with Chrome Azurol S using microwave treatment. The throughput of the system is 68 samples per hour, the analytical range for chromium(III) is 0.03-60 mg/L. Na, K, Mg, Ca, Zn, Cd, Pb, C1^-, SO ₄ ^2- , NO_3/-, CH₃COO^- in 1000-fold amounts; Cu(II) and F^- in 500-fold amounts; Fe(III) in a 10-fold amount; and Cr(VI) in a sevenfold amount do not interfere with the determination of Cr(III). Procedures for the photometric determination of chromium under batch conditions were developed. The accuracy of the developed procedures was verified in the analysis of tanning agents and dyes for leather. Deceased.     

食品中柠檬黄铝色淀和日落黄铝色淀的毛细管区带电泳分析

发展了一种新的采用毛细管区带电泳分析柠檬黄铝色淀和日落黄铝色淀的方法。通过前处理步骤成功实现了铝色淀中铝基质与色素的分离。利用石英毛细管柱（48.50 cm（有效长度40.00 cm）×50 μm）,分别针对柠檬黄铝色淀和日落黄铝色淀进行了电泳条件的优化,并得到最优分离结果。所建立的定量分析方法的检出限对于柠檬黄铝色淀和日落黄铝色淀分别达0.26 mg/L和0.27 mg/L,线性范围分别为0.53~1.3×10²mg/L和0.54~1.4×10²mg/L,两种被分析物的测定重复性（RSD,n=6）分别为4.3%和5.7%,日间重复性（RSD,n=6）分别为5.6%和6.0%。经过更深入研究后,该方法可以发展为食品中相应色淀的检测方法。     

Oxidation of SO2 to sulfate in sea salt aerosols

Summary In laboratory-scale experiments sea salt particles are exposed to SO₂ at a temperature of 22°C and relative humidities of 40, 60 and 80%; the SO₂ gas concentration is fixed to 0.2, 0.5 and 1.0 ppm (v), respectively. In further test series NO₂ is added to the gas phase. As kinetic data the capacity values of the sea salt particles (mg formed sulfate/g dry aerosol) are determined as function of time and from this the reaction rates (mg formed sulfate/g dry aerosol and minute) are calculated in dependence of the yield. The relative humidity (r.h.) has proved to be a decisive reaction parameter. For example, the rate (at a reaction time of one hour) increases at a SO₂ concentration of 0.5 ppm (v) from 0.01 to approx. 0.1 mg SO ₄ ^2– /g·min, if the r.h. will increase from 40 to 80%. However, the gas concentration has only an importance at high humidities (where the reaction takes place in droplets) for the sulfate formation in sea salt aerosols. If the SO₂ concentration is reduced from 1.0 to 0.2 ppm (v) at a r.h. of 80%, the rate will be decreased from 0.2 to about 0.07 mg SO ₄ ^2– /g·min; however, at a r.h. of 60% from 0.075 to 0.04 mg SO ₄ ^2– /g·min. As an increased sulfate formation but no nitrate formation can be detected when NO₂ is added to the gas phase, it can be assumed that SO₂ is oxidized in the electrolyte layer around the sea salt particles whereas NO₂ is reduced. If NO₂ (SO₂:NO₂=1:1) is added to the gas phase, the rate — for example at a r.h. of 40% — will be increased from 0.01 to 0.24 mg SO ₄ ^2– /g·min.     

Selective photometric determination of low conentrations of selenium(IV) and selenium(VI) in bottled drinking water

A procedure is developed for the selective photometric determination of selenium(IV) in bottled drinking water by the oxidation of Methylene Blue in 1 M HCl to colorless decomposition products and of selenium(VI) by its interaction with the specified reagent at pH 5–6 with the formation of a colored ion pair. The limits of detection are 1 and 0.8 µg/L, respectively. At the concentration of selenium(IV) 2 µg/L, the admissible weight ratios are: SeO₄^2-, Br₃^- (1: 20); Br^– (1: 60); I^–, IO₃^- and IO₄^- (1: 100). At equal concentration of selenium(VI), the following species: SeO₄^2-(1: 20); Br₃^-, Br^–, I^–, IO₃^-, and IO₄^- (1: 100) do not interfere with the determination. Other anions and cations present in highly mineralized waters do not interfere with the determination. The relative error of determination is 8–10% in the concentration range 2–10 µg/L of selenium(IV) and selenium(VI) and does not exceed 5% in their concentration range of 10–100 µg/L.     

Comparison of no gas and He/H2 cell modes used for reduction of isobaric interferences in selenium speciation by ion chromatography with inductively coupled plasma mass spectrometry

Inductively coupled plasma mass spectrometry (ICP-MS) used for the detection of most common selenium isotopes ⁷⁸Se (23.8%, abundance) and ⁸⁰Se (49.6%, abundance) is interfered in the presence of ³⁸Ar⁴⁰Ar⁺ and ⁴⁰Ar⁴⁰Ar⁺ in argon (Ar) gas. To address this issue, ICP-MS with an octopole reaction system (ORS) was explored for the detection of selenite and selenate, which was separated by anion-exchange chromatography. Results indicate that it was possible to detect ⁷⁸Se using no collusion gas, while to detect ⁸⁰Se a H₂ as the collusion/reaction gas was recommended since the background and noise were significantly reduced using H₂ as the gas. The selenium speciation interested was separated on a new column (G3154/101A, Agilent technologies) within 5 min using a mobile phase containing 10 mM NH₄H₂PO₄ and 20 mM NH₄NO₃ at pH 6.5. Linear plots were obtained in a concentration range of 1–200 μg/L with detection limits less than of 0.4 μg/L for ⁸⁰Se (IV) and 0.6 μg/L for ⁸⁰Se (VI) using H₂ as the reaction gas. Finally, the proposed method was used in the determination of selenium in water and soil.     

Residue analysis of onions and other foodstuffs with a complex matrix using two-dimensional capillary-GC with three selective detectors

Summary A very fast determination of sulphate in ground and drinking water by inductively coupled plasma emission spectrometry (ICP/OES) is described. The 182.037 nm line was selected for the measurement of the total sulphur content, because this line is not disturbed by calcium, one of the main components in natural waters. The limit of determination (0.5 mg/l SO ₄ ^2– ) is low enough for most aquatic samples. With a two point calibration the linear working range is between 0.5 and 100 mg/l SO ₄ ^2– .     

Determination of sulfite in water samples by flow injection analysis with fluorescence detection

<正>A fast,sensitive,and reliable method for the determination of sulfite(SO_3~(2-)) in fresh water and seawater samples was developed.The proposed method was based on the reaction of o-phthalaldehyde(OPA)-sulfite-NH_3 in alkaline solution,with flow injection analysis and fluorescence detection.The experimental parameters were investigated in pure water and seawater matrixes. The detection limits(S/N = 3) were 0.006μmol/L in pure water and 0.018μmol/L in seawater for SO_3~(2-).The method was successfully applied to analyze SO_3~(2-) in the samples of rain water and flue gas desulfurization seawater.