离子色谱-柱切换法测定土壤浸出液中的氟离子

建立了离子色谱-柱切换测定土壤浸出液中氟离子的方法。使用柱切换技术,将样品通过高聚物反相色谱柱进行在线预处理,分离氟离子和小分子有机酸,同时除去水溶性有机杂质,采用收集环收集氟离子并进入分析系统分析,消除了测定氟离子时普遍存在的干扰问题。分析系统的淋洗液为KOH溶液,流速为1.0 mL/min,采用抑制性电导检测,外标法定量。氟离子的线性范围为0.05~10.0 mg/L,相关系数为0.9999,加标回收率为103.4%~105.3%,相对标准偏差为2.0%~2.1%,检出限 (S/N=3)为5.50 μg/L。该方法适用于测定复杂基体样品中的氟离子。     

氟离子选择电极测定黄磷尾气中气态氟含量

采用NaOH溶液吸收黄磷尾气中气态氟,氟离子选择电极测定其氟含量。结果表明,电极电位与5~100.0μg/mL氟离子浓度的对数有良好的线性关系(R=0.99992)。相对标准偏差(RSD)为3.05%,平均回收率为98.70%~99.69%。该方法操作简便、干扰小、准确度高,分析成本低,适用于黄磷尾气中氟含量的测定。     

离子选择电极法测定食品添加剂硫酸钙中的氟离子

建立了氟离子选择性电极对食品添加剂硫酸钙中氟离子含量的测定方法,通过标准曲线法进行定量,线性相关系数为0.999 1,线性范围为0.2~3.0μg/mL,方法的相对标准偏差为3.2%,加标回收率为97.8%~102.0%,实验结果表明所建立的方法简单、快速、准确,适用于食品级硫酸钙中氟离子含量的测定。     

磁力搅拌-离子选择电极法测量铜精矿中的水溶性氟

建立磁力搅拌–离子选择电极法测定铜精矿中的水溶性氟。采用磁力搅拌法对样品进行前处理,研究了浸取温度、浸取时间、测量温度等因素对氟测定的影响,经试验确定浸取温度为50℃,浸取时间为180 min,测量温度为20℃。氟在0.5～2.5μg/mL范围内其质量浓度的自然对数与电位值呈良好的线性关系,相关系数r2=0.999 8,方法检出限为0.03μg/mL,定量限为0.1μg/mL。铜精矿样品测定结果的相对标准偏差为4.26%(n=6),加标回收率为97.9%～105.0%。该方法重现性好,操作简单,可用于铜精矿中水溶性氟的准确定量分析。     

在线超滤-离子色谱法测定降水中4种阴离子

建立在线超滤–离子色谱法测定降水中4种阴离子。采用在线超滤技术,以Metrosep A Supp 5–150色谱柱为分析柱,3.2 mmol/L Na_2CO_3–1.0 mmol/LNaHCO_3溶液为淋洗液,流量为0.7 mL/min,0.5%H_2SO_4为抑制器再生液,用离子色谱法对降水中4种阴离子进行测定。氟离子、氯离子、硝酸根离子、硫酸根离子质量浓度在各自范围内与色谱峰面积呈良好的线性关系,相关系数均大于0.999,方法检出限为0.005～0.015 mg/L。测定结果的相对标准偏差为0.7%～2.2%(n=6),样品加标回收率为97.0%～103.0%。该法操作简单、成本低,适于大气降水中阴离子的测定。     

高温热水解-离子色谱法测定铬矿中氟含量

建立了一种快速、准确的离子色谱法测定铬矿中氟含量的方法,将铬矿与石英砂混合,控制氧气和水蒸气的流量,于1 100℃高温下热水解30min,水解液经吸收后,选用Dionex AS11-HC阴离子分析柱,以KOH(20mmol/L)作淋洗液,自动再生抑制型电导检测器检测,离子色谱法测定铬矿中氟的含量。方法的检出限为0.022μg/mL,定量限为0.073μg/mL,方法的检测范围为0.0015%~0.20%,加标回收率在92%~101%。应用于实际样品的测定结果表明,铬矿中氟含量的测定值与标准方法的测定值一致。方法简单快速、检出限低、精密度高、准确度好。能满足铬矿中氟含量的快速准确检测要求。     

GC—MS-相转移衍生化法分析水相中亚硝酸根离子

采用相转移催化剂四辛基溴化铵及五氟苄基溴将水相(血、尿)中亚硝酸根离子衍生化生成可挥发性化合物,然后用GC-MS法进行测定.亚硝酸根离子含量在0.2～10 μg/ mL范围内与离子峰面积呈良好的线性关系,相关系数r=0.9998,检出限为0.1 μg / mL.用该方法对水、尿、血中亚硝酸根离子进行测定,测定结果的相对标准偏差为1.44%～4.17%(n=6),回收率为82%～84%.     

造纸法烟草薄片浆液、白水及成品中铝的测定

采用氟离子选择电极法测定造纸法烟草薄片浆液、白水及成品中的铝。研究了影响测定结果的主要因素,确定了适宜的测定条件。结果表明:当F-的初始浓度为1×10-3mol/L时,电极电位(E)与铝量(ρ)线性关系良好(R=0.9996),线性范围为2.0~10.0μg/mL,回收率为84.71%~88.42%,RSD为0.57%~3.1%。该法通过控制溶液中氟离子浓度从而实现铝的测定,方法适合于样品中铝的分析。     

在酸性介质中用氟电极测定氟离子的新方法

基于弱酸根离子在不同酸度溶液中的化学平衡和离子选择电极的响应特征, 本文推导出了以氟电极为指示电极, 玻璃pH电极作参比在酸性介质中测定氟的新方法. 经验证： 当pH＜2时, 氟离子浓度在10^-2～10^-5 mol/L范围内, 电池电动势值与氟离子总量呈能斯特响应, 试液中少量铝的存在对测定不构成干扰. 用该法直接测定了酸蚀法铝型材废水中的氟, 加标回收率达96%～98%.     

QuEChERS-气相色谱/质谱法测定牛奶中氟虫腈及其代谢物的残留量北大核心CSCD

建立了QuEChERS-气相色谱/质谱法测定牛奶中氟虫腈及其代谢物氟甲腈、氟虫腈砜、氟虫腈硫醚残留量。样品经QuEChERS法提取净化,采用DB-5MS柱进行分离,选择离子模式下同时测定,外标法定量。结果表明,氟虫腈及其代谢物在0.01~0.50μg/mL质量浓度范围内均呈良好的线性关系,相关系数R^(2)>0.997,该方法检出限为0.30~0.68μg/kg,定量限为0.90~1.20μg/kg。在加标水平分别为0.01、0.10、0.50 mg/kg下,4种化合物的回收率范围为83.7%~112.6%,相对标准偏差范围为1.8%~4.2%。该方法简单快捷、准确可靠,适用于牛奶中氟虫腈及其代谢物的同时测定。     

A highly sensitive fluorimetric method for the determination of fluoride in biological material with Al3+-calcein complex

A highly sensitive fluorimetric method for the determination of fluoride was established. The method was based on quenching of the fluorescence of the Al³⁺-calcein complex in CCl₃COOH-CH₃COOK buffer solution by fluoride. The fluorescence emission was measured at λ_ex/λ_em 480/503 nm, and the experimental variables and interference in this determination were studied. The linear calibration range was 0.8 ng/mL to 150 ng/mL and the detection limit was 0.2 ng/mL. The method was applied to determine fluoride in biological materials. The recovery was in the range of 96.3% to 104.7% and the relative standard deviation was 4.6%. The results obtained from the certified reference material by the present method agreed with the certified values.     

A highly sensitive fluorimetric method for the determination of fluoride in biological material with Al3+-calcein complex

A highly sensitive fluorimetric method for the determination of fluoride was established. The method was based on quenching of the fluorescence of the Al3+-calcein complex in CCl3COOH-CH3COOK buffer solution by fluoride. The fluorescence emission was measured at lambdaex/lambdaem 480/503 nm, and the experimental variables and interference in this determination were studied. The linear calibration range was 0.8 ng/mL to 150 ng/mL and the detection limit was 0.2 ng/mL. The method was applied to determine fluoride in biological materials. The recovery was in the range of 96.3% to 104.7% and the relative standard deviation was 4.6%. The results obtained from the certified reference material by the present method agreed with the certified values.     

锆-氟-7-碘-8-羟基喹啉-5-磺酸-EDTA-表面活性剂体系的荧光光度研究

在pH5.5～7.0的HAc-NaAc缓冲溶液中,锆与氟、7-碘-8-羟基喹啉-5-磺酸(H_2QSI)、EDTA及十六烷基三甲基溴化铵(CTMAB)形成五元荧光络合物,其组成为Zr(Ⅳ):F:H_2QSI:EDTA:CTMAB=1:2:1:1:4.络合物的最大激发波长(λ_(ex))为365nm,最大发射波长(λ_(em))为 500 nm.由此建立了锆的选择性好、灵敏度高的荧光测定新方法.方法的检测限为 0.8μg/L.测锆的线性范围为 0.0016～1.04 mg/L.应用于合金中锆的测定,结果满意.     

环境水中低含量氟化物的离子色谱分析

建立了离子色谱仪测定环境水中氟离子的方法.优化了试验条件,即淋洗液选1.8 mmol/L Na_2CO_3-1.7mmol/L NaHCO_3,流速0.8 m L/min.试验选择了活性炭作为固体吸附剂,采用固相萃取消除环境水中有可能存在的痕量乙酸对检测F~-的干扰.方法的检出限为0.022 2 mg/L,回收率为97.6%~98.9%,相对标准偏差小于2%.结果表明方法处理简单、准确度高,可用于环境水中低含量氟化物的测定.     

Rapid method for the determination of trace fluoride and activation of ion-selective electrode.

A method for activating ISE is proposed that can allow determination of the fluoride concentration at ng mL(-1) level with good precision and accuracy. Fluoride ISE is activated in 0.5 mol L(-1) HClO4 medium and then fluoride is determined in the same medium. The linear range for the determination of fluoride is between 1.00 x 10(-2)-1.00 x 10(-7) mol L(-1), and the detection limit of the method is 1.0 ng mL(-1). The advantage of this method is that it is free from the use of TISAB solution while being, time-saving and labor-saving. A mechanism study of the activation of FISE in HClO4 medium is explained. The method has been used for the determination of trace fluoride in milk and flour with satisfactory results.     

Determination of fluoride by an ion chromatography system using the preconcentration on nanometer-size zirconia

A simple rapid microcolumn preconcentration technique is described for the determination of fluoride ions in geological samples through the ion chromatography system. The technique is based on the adsorption of fluoride ions on H₂SO₄-activated nanometer-size zirconia (NSZ) packed in a microcolumn. Activation parameters (concentration and contact time) were studied, and an activation time of about 50 min and a concentration of 6 M were then selected. The analytical procedure was optimized in terms of the flow rate of the sample solution, eluent concentration, and the eluent flow rate for the adsorption capacities of H₂SO₄-activated NSZ. At a flow rate of 1.0 mL/min, the detection limits (3σ) of the technique for fluoride ions was 0.3 ng/mL, and the RSD was 0.04%. The dynamic adsorption capacity of NSZ was found to be 8.4 mg/g. The text was submitted by the authors in English.     

EDTA滴定法测定萤石中氟化钙含量的方法改进

建立了EDTA滴定法测定矿石中氟化钙的方法。引入了钙乙酸为溶解试样的溶剂,溶解样品中的碳酸钙,同时,通过同离子效应减少氟化钙的溶解度。实验中探究了钙离子的浓度与氟化钙溶解度的关系,通过对比实验确定选择了含钙乙酸的最佳浓度(10g/L)。同时,对实验中的其他条件也进行了相应的探究与优化,确定最佳实验条件为:最小称样量为0.5g,洗涤沉淀用水量为50mL左右,第二次过滤时的洗涤次数为8～10次,滴定时加入氢氧化钾的量为20mL。方法的精密度(0.10%)和准确度(0.08%)皆能满足实验要求。     

EDTA滴定法测定萤石中氟化钙含量的方法改进

建立了EDTA滴定法测定矿石中氟化钙的方法。引入了钙乙酸为溶解试样的溶剂,溶解样品中的碳酸钙,同时,通过同离子效应减少氟化钙的溶解度。实验中探究了钙离子的浓度与氟化钙溶解度的关系,通过对比实验确定选择了含钙乙酸的最佳浓度(10g/L)。同时,对实验中的其他条件也进行了相应的探究与优化,确定最佳实验条件为:最小称样量为0.5g,洗涤沉淀用水量为50mL左右,第二次过滤时的洗涤次数为8～10次,滴定时加入氢氧化钾的量为20mL。方法的精密度(0.10%)和准确度(0.08%)皆能满足实验要求。     

EDTA滴定法测定矿石中铅含量的方法改进

对以往测定铅的方法进行了改进。消解样品的体系为盐酸-硝酸-硫酸和氟化铵,氟化铵(200 g/L)的加入量为3 mL;硫酸加入量为10 mL,浓度为1+1;硫酸铅沉淀静止时间为45 min;除去铋干扰的方法为调节溶液的pH值用EDTA溶液进行分步滴定;将过滤后的滤液进行回收测定,与滴定的结果相加以得到最终结果,滤液中铅含量的大概范围为0.13 %~0.27 %。本方法的精密度为0.12%~0.15% ,准确度为0.24%~0.43%。     

Direct inhibition of Re Du Ning Injection and its active compounds on human liver cytochrome P450 enzymes by a cocktail method

The aim of this study was to investigate the direct inhibitory effects of Re Du Ning Injection (RDN) and its active compounds on the major cytochrome P450 enzyme (CYP) isoforms (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 and CYP3A4) of human liver microsomes by ‘a cocktail method’. The activity of each CYP isform was represented as the formation rate of the specific metabolite from relevant substrate. Then a sensitive and specific ultra‐performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was developed and validated to simultaneously analyze the seven metabolites. RDN (0.035–2.26 mg/mL) showed a strong inhibitiory effect on CYP2C8, followed by CYP2C9, CYP2B6, CYP2C19, CYP1A2 and CYP3A4. The IC₅₀ value for each enzyme was 0.19, 0.66, 0.72, 1.27, 1.66 and 2.13 mg/mL, respectively. RDN competitively inhibited the activities of CYP1A2 (K _i = 1.22 mg/mL), CYP2B6 (K _i = 0.65 mg/mL) and CYP3A4 (K _i = 0.88 mg/mL); it also exhibited mixed inhibition of CYP2C8, CYP2C9 and CYP2C19 with a K _i value of 0.26, 0.64 and 0.82 mg/mL, respectively. However, the activity of CYP2D6 was not significantly inhibited even by 2.26 mg/mL RDN. Moreover, the data of nine active compounds on the CYPs showed that cryptochlorogenin acid, sochlorogenic acid B and sochlorogenic acid C were the major contributors to the inhibitory effect of RDN on CYP2C8, while the inhibitory effect of RDN on CYP2C9 might be caused by sochlorogenic acid A and sochlorogenic acid C. Moreover, neochlorogenic acid might be the major contributor to the inhibitory effect on CYP2B6. All of the findings suggested that drug–drug interactions may occur and great caution should be taken when RDN is combined with drugs metabolized by these CYPs.