KBrO3-KBr紫外分光光度法测定痕量苯酚

研究了在盐酸介质中以 KBrO3-KBr 紫外分光光度法测定痕量苯酚的条件,在浓度为 0.6mol/L HCl,3×10-5mol/L KBrO3,5×10-4mol/L KBr,6×10-4mol/L KI 溶液中测定苯酚时,线性范围为 0.10～2.5mg/L,表观摩尔吸光系数为 1.89×104L·mol-1·cm-1,Sandell 指数为 4.98μg/cm2.本法已用于测定废水中苯酚.     

流动注射化学发光法测定水样中痕量间苯二酚

基于在甲醛存在条件下,高锰酸钾在酸性介质中氧化间苯二酚而发生化学发光反应,建立了测定痕量的间苯二酚化学发光分析法.该法测定间苯二酚的线性范围为5.0×10-9～1.0×10-4mol/L,检出限为3.0×10-9mol/L,相对标准偏差为3.5%(1.0×10-6mol/L间苯二酚,n=11).该法应用于测定水样中加入的间苯二酚,结果令人满意.     

Ru（bipy）3^2＋—CO3^2——SO3^2——KClO3体系化学发光法测定空气中的二氧化硫

提出了Ru(bipy) 2+ 3-CO 2- 3-SO 2- 3-KClO 3体系化学发光法测定溶液中亚硫酸盐的方法.SO 2- 3浓度与化学发光强度在1.0×10-7～1.0×10-4 mol/L 范围内成正比,检出限为8.76×10-8 mol/L,对1.0×10-4 mol/L SO2-3溶液6次测定的相对标准偏差为2.9%.该法用三乙醇胺作为吸收液,成功地用于测定空气中二氧化硫的含量,结果满意.     

夜蓝与阴离子表面活性剂在水溶液中显色反应——吸光光度法测定环境水样中阴离子表面活性剂

在聚乙烯醇存在的1.8mol/L磷酸溶液中,夜蓝与阴离子表面活性剂形成离子缔合物。溶液由绿色变为蓝色,可用于水相直接光度测定阴离子表面活性剂。最大吸收波长555nm,摩尔吸光系数分别为5.72×10~4L·mol~(-1)·cm~(-1)(十二烷基苯磺酸钠),5.77×10~4 L·mol~(-1)·cm~(-1)(十二烷基硫酸钠),4.36×10~4 L·mol~(-1)·cm~(-1)(十二烷基磺酸钠)。方法简便、快速,具有良好的选择性。可用于河水和生活废水中10~(-6)—10~(-7)mol/L阴离子表面活性剂的测定。     

磷钼杂多酸光度法测定吲哚乙酸

研究了吲哚乙酸与磷钼杂多酸在浓度为 0 .0 3 mol/L的硫酸介质中发生氧化还原反应 ,形成的还原产物 (钼蓝 )在 NH3-NH4Cl缓冲溶液 (p H8.4)中最大吸收波长为 314 nm,表观摩尔吸光系数 ε值为 3.5 4× 10 4L· mol-1·cm-1 ,吲哚乙酸含量在 5 .0× 10 -7～ 5 .0× 10 -5 mol/L范围内符合比尔定律 ,检出限为 1.0× 10 -7mol/L,对 2 .0 0× 10 -5 mol/L吲哚乙酸测定 10次的相对标准偏差为 6 .42 % ,加标回收率为 94.2 %～ 10 0 .1%     

荧光光度法测定苯二酚异构体中的邻苯二酚

用荧光光度法测定苯二酚异构体中的邻苯二酚。在硼砂缓冲溶液介质中,氰乙酰胺能与邻苯二酚生成荧光物质,在最佳实验条件下,邻苯二酚的浓度在1×10~(-8)～3×10~(-6)mol/L范围内与荧光强度呈线性关系,检出限为6.2×10~(-9)mol/L,对苯二酚和间苯二酚不干扰测定。     

Ru(bipy)_3~(2+)-CO_3~(2-)-SO_3~(2-)-KClO_3体系化学发光法测定空气中的二氧化硫

提出了 Ru(bipy) 2 +3 - CO2 -3 - SO2 -3 - KCl O3 体系化学发光法测定溶液中亚硫酸盐的方法。SO2 -3 浓度与化学发光强度在 1 .0× 1 0 - 7～ 1 .0× 1 0 - 4mol/L 范围内成正比 ,检出限为 8.76× 1 0 - 8mol/L,对 1 .0× 1 0 - 4mol/L SO2 - 3 溶液 6次测定的相对标准偏差为 2 .9%。该法用三乙醇胺作为吸收液 ,成功地用于测定空气中二氧化硫的含量 ,结果满意。     

顺序注射化学发光联用技术测定食品中的碘

基于酸性溶液中HCHO存在下,KMnO4可氧化I-产生很强的化学发光的原理,建立了一个简单快速测定微量碘的顺序注射化学发光分析方法。I-在3.0×10-8~8.0×10-6mol/L范围内与发光强度呈良好线性关系。对2.0×10-6mol/L I-11次重复测定的相对标准偏差(RSD)为2.6%,方法的检出限(3σ)1.3×10-8mol/L,测定了4种食品中的碘量,回收率为92.8%~107.7%。分析频率为70 h。     

毛细管电泳-电化学检测测定茶叶中咖啡因、表儿茶素和抗坏血酸

高效毛细管电泳电化学检测同时测定了6种茶叶中的咖啡因、表儿茶素和抗坏血酸的含量,考察了实验参数对分离、检测的影响。在最佳实验条件下,以300 靘直径的碳圆盘电极为检测电极,检测电极为1.20 V(vs.SCE),在25 mmol/L硼酸盐25 mmol/L磷酸盐(pH 7.6)的混合运行缓冲液中,上述各组分在16 min内能完全分离。咖啡因、表儿茶素和抗坏血酸在2×10-3mol/L～１×10-5 mol/L、5×10-5mol/L～5×10-7mol/L、2×10-4 mol/L～1×10-5mol/L范围内呈线性关系,检测下限分别为6×10-6mol/L、4×10-7mol/L和1×10-6mol/L。该法直接用于茶叶中咖啡因、表儿茶素和抗坏血酸的测定,结果令人满意。     

四种阴离子的毛细管电泳电导检测(英文)

 采用柠檬酸 柠檬酸钠作为缓冲体系 ,使用负高压 ,对Cl-,NO3 -,HCO3 -和H2 PO4 -等 4种常见阴离子进行了分离检测 ,研究了缓冲剂的种类、浓度、pH值及操作电压对分离的影响。在选定的条件下 ,4种离子的定量线性范围 :Cl-5 0× 10 -5mol/L～ 2 5× 10 -3 mol/L ,NO3 -6 0× 10 -5mol/L～ 2 0× 10 -3 mol/L ,HCO3 -5 0× 10 -6mol/L～ 2 0× 10 -4 mol/L ,H2 PO4 -6 0× 10 -5mol/L～ 1 0× 10 -3 mol/L ;检出限 :Cl-1 5× 10 -5mol/L ,NO3 -3 0×10 -5mol/L ,HCO3 -1 0× 10 -6mol/L ,H2 PO4 -2 0× 10 -5mol/L ;峰面积的RSD (n =6 ) :Cl-3 1% ,     

Influence of Potassium Metal-Support Interactions on Dendrite Growth

Combined synchrotron X-ray nanotomography imaging, cryogenic electron microscopy (cryo-EM) and modeling elucidate how potassium (K) metal-support energetics influence electrodeposit microstructure. Three model supports are employed: O-functionalized carbon cloth (potassiophilic, fully-wetted), non-functionalized cloth and Cu foil (potassiophobic, nonwetted). Nanotomography and focused ion beam (cryo-FIB) cross-sections yield complementary three-dimensional (3D) maps of cycled electrodeposits. Electrodeposit on potassiophobic support is a triphasic sponge, with fibrous dendrites covered by solid electrolyte interphase (SEI) and interspersed with nanopores (sub-10 nm to 100 nm scale). Lage cracks and voids are also a key feature. On potassiophilic support, the deposit is dense and pore-free, with uniform surface and SEI morphology. Mesoscale modeling captures the critical role of substrate-metal interaction on K metal film nucleation and growth, as well as the associated stress state.     

Cleavage of different ether bonds in butyl glycidyl ether and allyl glycidyl ether by K, K(15-crown-5)2

The kind of substituent in alkyl glycidyl ethers affects the course of their reaction with K⁻, K⁺(15-crown-5)₂. The cyclic oxirane ring is exclusively cleaved in the case of butyl glycidyl ether whereas the presence of the unsaturated allyl group in the glycidyl ether molecule unexpectedly prefers the scission of the linear ether bond. In both the systems organometallic intermediates are formed. They react with crown ether causing its ring opening. Allylpotassium formed from allyl glycidyl ether reacts also with another glycidyl ether molecule; the oxirane ring is opened in this case.     

痕量碘离子的铬(Ⅵ)-碱性呫吨染料体系分光光度法测定

在过量溴化物存在下的稀磷酸介质中 ,I-被Cr(Ⅵ )氧化成I2 后与Br-结合形成[I2Br] -配阴离子 ,该配阴离子能进一步与罗丹明6G、罗丹明B、吖啶红等碱性吨染料阳离子形成离子缔合配合物。在聚乙烯醇存在下 ,缔合物体系稳定且溶液颜色有明显的变化 ,可用于I-离子的光度测定。方法具有高灵敏度 ,不同体系的摩尔吸光系数在4 .96×104 ～1 .1×105 L·mol-1·cm-1 之间 ,以罗丹明6G和罗丹明B体系灵敏度较高。碘离子质量浓度分别在0～0.8mg/L(罗丹明B和罗丹明6G体系)、0～1.0mg/L(吖啶红体系 )之间遵守比尔定律。方法具有良好的选择性 ,用于海带、黄豆和含碘药片的测定结果令人满意     

几种钛酸钾纤维的合成及其相关性研究

本文以Ｋ＿２ＣＯ＿３和ＴｉＯ＿２为主要原料，采用混练－干燥－煅烧三步法合成出了Ｋ＿２Ｔｉ＿２Ｏ＿５、Ｋ＿２Ｔｉ＿４Ｏ＿９、Ｋ＿２Ｔｉ＿６Ｏ＿１３三种形式的钛酸钾纤维物质。测定了它们的ＸＲＤ、ＤＴＡ－ＴＧ、ＳＥＭ、ＩＣＰ、激光拉曼等有关特征数据和谱图，并对它们之间的相互关系进行了研究。     

流动注射化学发光法测定青霉素G钾

在甲醛的存在下,酸性KMnO4与青霉素G钾能够产生很强的化学发光,从而建立了KMnO4-甲醛-青霉素G钾化学发光体系来测定青霉素G钾.青霉素G钾的测定线性范围为2.0×10-7～1.0×10-5 g/mL,方法的检出限为1.4×10-7 g/mL,对4.0×10-7 g/mL的青霉素G钾进行11次平行测定,相对标准偏差为1.0%,用此法测定青霉素G钾取得了较好的结果.     

New facts concerning the reaction of K, K(15-crown-5)2 with phenyl glycidyl ether: unexpected formation of potassium cyclopropoxide

A new mechanism of the reaction of K⁻, K⁺(15-crown-5)₂ with phenyl glycidyl ether is presented. The linear ether bond is attacked only to a small extent, if at all. As the main reaction path the oxirane bond in the β-position is cleaved, followed by the γ-elimination of potassium phenoxide and the formation of potassium cyclopropoxide. Crown ether ring opening also occurs in reactions with organometallic intermediates.     

四元体系KCl-K2SO4-CO(NH2)2-H2O有25℃时的等温溶度研究

测定了四元体系KCl－K₂SO₄－CO(NH₂)₂－H₂O及边界三元体系K₂SO－CO(NH₂)₂-H₂O在25℃时的溶度及饱和溶液密度值和折光率,绘制了相应的溶度图及相应的组成-性质图.测定并绘制了该四元体系K₂SO₄单饱区的溶度面、折光率面和密度面图.两个体系的溶度图均属于低共饱型,平衡固相为组份化合物.     

Potassium phthalimide promoted green multicomponent tandem synthesis of 2-amino-4H-chromenes and 6-amino-4H-pyran-3-carboxylates

A one-pot efficient, green, practical, and environmentally friendly multicomponent synthesis of 5-oxo-4-aryl-5,6,7,8-tetrahydro-4H-chromenes, ethyl-6-amino-4-aryl-5-cyano-2-methyl-4H-pyran-3-carboxylates as well as 2-amino-4-aryl-7-hydroxy-4H-chromene-3-carbonitriles via tandem the Knoevenagel-cyclocondensation has been described in the presence of a green, low-cost, mild, efficient, and commercially available potassium phthalimide as the organocatalyst. This technique is a safe and ecofriendly approach to the synthesis of different 4H-chromens and 4H-pyrans that offers many merits including short reaction times, high yields, straightforward work-up, and no use of hazardous organic solvents.     

Das Mischkristallsystem K2OsCl6

The Mixed Crystal System K₂OsCl₆? K₂SnCl₆ Homogeneous mixed crystals between K₂OsCl₆ and K₂SnCl₆ have been prepared in any composition ratio by precipitation from concentrated K₂OsCl₆/K₂SnCl₆ solutions with concentrated hydrochloric acid. The lattice constants follow Vegard's rule.     

Crystal structure,spectroscopic and thermal studies of anhydrous potassium 2,6-dihydroxybenzoate

The crystal structure, infrared spectrum and thermal stability of the potassium salt of 2,6-dihydroxybenzoic acid have been studied. The compound crystallizes in the monoclinic space group P2₁/n with a = 3.847(1) Å, b = 15.099(5) Å, c = 13.248(4) Å, β = 98.35(2)° and Z = 4. The compound of the general formula KL is a three-dimensional polymer, in which K ions are bridged by coordinated organic ligands by oxygen atoms of carboxylate and hydroxy groups. The anhydrous compound decomposes at 230°C. The IR spectrum of the potassium salt is discussed.