Indirect determination of cefradine with n-propyl alcohol–ammonium sulfate–water system by extraction–flotation of cuprous thiocyanate

A new method was developed for the determination of cefradine by extraction-flotation of CuSCN. The experiment indicated that in the presence of 0.20 mol/L NaOH the degradation of cefradine took place in water bath at 100 ℃. The thiol group （-SH） of the degradation product could reduce Cu（Ⅱ） to Cu（Ⅰ） for the formation of the emulsion CuSCN in the presence of NH4SCN at pH 4.0. By determining the residual amount of Cu（Ⅱ） in the solution and calculating the flotation yield of Cu（Ⅱ）, the indirect determination of cefradine can be obtained. This method has been applied to determine cefradine in capsules, human serum and urine samples, respectively.     

硫普罗宁的药代动力学及光度法测定

建立了光度法测定硫普罗宁的新方法。研究表明:在SCN-和KNO3存在下,控制溶液pH4.0,Cu(II)被硫普罗宁还原生成的Cu(I)与SCN-反应形成CuSCN沉淀,该沉淀能浮在水相表面。通过测定溶液中剩余Cu(II)的量,可以测定硫普罗宁的含量。吸光度与硫普罗宁浓度之间存在良好线性关系。线性方程:A=4.898-0.3616ρ(μg/mL),线性范围为0.25～12.0μg/mL,相关系数R=0.9993,检出限为0.16μg/mL。该方法可直接用于药物中硫普罗宁含量的测定及其药代动力学行为研究。     

Indirect Determination of Sodium Cefotaxime with N‐Propyl Alcohol‐Ammonium Sulfate‐Water System by Extraction‐Flotation of Cuprous Thiocyanate

A novel method for the indirect determination of sodium cefotaxime by the extraction‐flotation of cuprous thiocyanate is described in this paper. The experiment indicated that the degradation of sodium cefotaxime took place in the presence of 0.20 M sodium hydroxide in a boiling water bath for 40 min. At pH 4.0, the thiol group (‐SH) of the degradation product of sodium cefotaxime could reduce Cu(II) to Cu(I) for the formation of the emulsion CuSCN precipitation in the presence of ammonium thiocyanate. By determining the residual amount of Cu(II) in the solution and calculating the flotation yield of CuSCN, the indirect determination of sodium cefotaxime can be achieved. When the concentration of Cu(II) was 5.0 μg mL^?1, a good linear relationship was obtained between the flotation yield of CuSCN and the amount of sodium cefotaxime in the range of 0.50～20 μg mL^?1. The linear equation is E = 1.329 + 2.654C with a correlation coefficient r = 0.9988. The detection limit of sodium cefotaxime of this proposed method evaluated by calibration curve (3σ/k) was found to be 0.39 μg mL^?1. Every parameter has been optimized and the reaction mechanism has been studied. This method has been successfully applied to the determination of sodium cefotaxime in pharmaceutical formulations, human serum, and urine samples, respectively. Analytical results obtained with this novel method are satisfactory.     

Indirect determination of thiamazole with the <Emphasis Type="Italic">n</Emphasis>-propyl alcohol-ammonium sulfate-H<Subscript>2</Subscript>O system by the extraction-flotation of CuSCN

In this paper, a new method for the determination of thiamazole by the extraction-flotation of CuSCN with n-propyl alcohol-ammonium sulfate-H₂O system was described. The experiment indicated that in the presence of SCN⁻, Cu(II) was reduced to Cu(I) by thiamazole because of the formation of CuSCN. In the course of phase separation of n-propyl alcohol from water, the precipitated CuSCN remained at the interface of n-propyl alcohol and water. A good linear relationship was obtained between the flotation yield of CuSCN and the amount of thiamazole. The detection limit of thiamazole was found to be 0.12 μg/mL and the linear range was 0.15–4.0 μg/mL with a correlation coefficient 0.9995. As a preliminary application, this method has been successfully applied to the determination of thiamazole in pharmaceutical formulations, human plasma and urine samples. The recoveries were in the range 98–103%, and the relative standard deviation values were not higher than 3.08%. The text was submitted by the authors in English.     

Mechanochemical and solution synthesis, X-ray structure and IR and 31P solid state NMR spectroscopic studies of copper(I) thiocyanate adducts with bulky monodentate tertiary phosphine ligands

A number of adducts of copper(I) thiocyanate with bulky tertiary phosphine ligands, and some nitrogen-base solvates, were synthesized and structurally and spectroscopically characterised. CuSCN:PCy3 (1:2), as crystallized from pyridine, is shown by a single crystal X-ray study to be a one-dimensional polymer ...(Cy3P)2CuSCN(Cy3P)2CuSCN... (1) with the four-coordinate copper atoms linked end-on by S-SCN-N bridging thiocyanate groups. A second form (2), obtained from acetonitrile, was also identified and shown by IR and 31P CPMAS NMR spectroscopy to be mononuclear, with the magnitude of the dν(Cu) parameter measured from the 31P CPMAS and the ν(CN) value from the IR clearly establishing this compound as three-coordinate [(Cy3P)2CuNCS]. Two further CuSCN/PCy3 compounds CuSCN:PCy3 (1:1) (3), and CuSCN:PCy3:py (1:1:1) (4) were also characterized spectroscopically, with the dν(Cu) parameters indicating three- and four-coordinate copper sites, respectively. Attempts to obtain a 1:2 adduct with tri-t-butylphosphine have yielded, from pyridine, the 1:1 adduct as a dimer [(Bu(t)3P)((SCN)(NCS))Cu(PBu(t)3)] (5), while similar attempts with tri-o-tolylphosphine (from acetonitrile and pyridine (= L)) resulted in solvated 1:1:1 CuSCN:P(o-tol)3:L forms as dimeric [{(o-tol)3P}LCu((SCN)(NCS))CuL{P(o-tol)3}] (6 and 8). The solvent-free 1:1 CuSCN:P(o-tol)3 adduct (7), obtained by desolvation of 6, was characterized spectroscopically and dν(Cu) measurements from the 31P CPMAS NMR data are consistent with the decrease in coordination number of the copper atom from four (for 6) (P,N(MeCN)Cu,S,N) to three (for 7) (PCuS,N) upon loss of the acetonitrile of solvation. These results are compared with those previously reported for mononuclear and binuclear PPh3 adducts which demonstrate a clear tendency for the copper centre to remain four-coordinate. The IR spectroscopic measurements on these compounds show that bands in the far-IR spectra provide a much more definitive criterion for distinguishing between bridging and terminal bonding than does an often-used empirical rule based on ν(CN) in the mid-IR, which leads to the wrong conclusion in some cases.     

The Study of Indirect Determination of Tiopronin by Extraction Flotation Copper(II) with an Ammonium Sulfate‐Water‐n‐Propyl Alcohol System

A novel method for indirect determination of tiopronin by extraction flotation of copper(II) with an ammonium sulfate‐water‐n‐propyl alcohol system was developed. The effects of different parameters, such as acidity, the amount of NH₄SCN and various salts on the flotation yield of Cu(II), have been studied to optimize the experimental conditions. Under the optimum conditions, Cu(II) is reduced to Cu(I) by tiopronin, and the resulting Cu(I) can react with SCN^? to form a white emulsion precipitate CuSCN. In the presence of (NH₄)₂SO₄, the mixture consisting of n‐propyl alcohol and water can be separated into an n‐propyl alcohol phase and a water phase. In the process of phase separation of n‐propyl alcohol from water, the precipitated CuSCN is extracted and stays in the interface of n‐propyl alcohol and water. The amount of tiopronin can be determined by measuring the flotation yield of Cu(II). The detection limit is 0.32 mg L^?1 and the linear range is maintained in the range of 0.40±13.0 mg L^?1 with a correlation coefficient of 0.9991. This proposed method has been successfully applied to the determination of tiopronin in tablets, urine and human plasma with satisfactory results.     

Indirect Determination of Ascorbic Acid with Ammonium Sulfate and Ethanol by Extraction and Flotation of Copper

A new method of indirect determination of ascorbic acid with ammonium sulfate and ethanol by extraction and flotation of copper in the presence of thiocyanate has been studied in this paper. The study shows that a small amount of Cu(II) is reduced to Cu(I) by ascorbic acid, then Cu(I) precipitates with SCN^?. In the course of phase separation of ethanol from water, the precipitated CuSCN is extracted and stays in the interface of ethanol and water. A good linear relationship is observed between the extraction yield of Cu(II) and the amount of ascorbic acid. The detection limit for ascorbic acid is 1 10^?5 M. Every parameter has been optimized and the reaction mechanism has been studied. The method is simple, rapid (5 min) and suffers from few interferences of common anions and cations. It has been successfully applied for the determination of ascorbic acid in pharmaceuticals and fruits.     

以Cu(II)为光谱探针离子分光光度法测定异烟肼的新方法

以Cu(II)为光谱探针建立了一种高选择性、高灵敏度测定异烟肼的新方法。试验表明：在pH 6.0时，Cu(II)可被异烟肼还原生成Cu(I)，反应生成的Cu(I) 与SCN-反应生成CuSCN白色乳状沉淀，在硝酸钠的存在下该沉淀可被浮选至水相表面。通过测定水相中剩余Cu(II)的量，可以间接测定异烟肼的含量。已反应Cu(II) 的量与异烟肼的浓度呈良好的线性关系，线性范围为0.050-4.50 µg mL-1，检出限为0.048 µg mL-1。该法已经成功的用于药物样品和病人尿液样品中异烟肼含量的测定。     

不同温度下选择性合成硫氰酸亚铜与硫化亚铜微晶

Hexagonal CuSCN and cubic Cu₂S micro-scale crystallites have been selectively fabricated using CuCl₂·2H₂O and KSCN as the starting materials at 30 ℃ and 220 ℃, respectively. The results reveal that the reaction temperature plays a key role in obtaining pure phase of CuSCN and Cu₂S crystallites. Nearly monodispersed Cu₂S nanocrystals were prepared by introducing surfactant into reaction system. The possible reaction mechanism is also discussed.     

Indirect determination of thiocyanate with ammonium sulfate and ethanol by extraction-flotation of copper

A new method for the indirect determination of thiocyanate with ammonium sulfate and ethanol by extraction-flotation of copper in the presence of ascorbic acid is described. A small amount of Cu(II) is reduced to Cu(I) by ascorbic acid, then Cu(I) is precipitated with SCN-. In the course of phase separation of ethanol from water, the precipitated CuSCN stays in the interface of ethanol and water. A good linear relationship is observed between the flotation yield of Cu(II) and the amount of SCN-. Using 1.0 ml of 1 x 10(-3) M ascorbic acid solution, 50 micrograms of Cu(II), 3.5 g of (NH4)2SO4 and 3.0 ml of ethanol with a total volume of 10 ml, the concentration of thiocyanate could then be determined by determining the flotation yield of Cu(II). The detection limit for thiocyanate is 5 x 10(-5) M. Every parameter was optimized and the reaction mechanism was studied. The method is simple and rapid and it was successfully applied to the determination of thiocyanate in urine and saliva of smokers and non-smokers and in venous blood of patients infused with sodium nitroprusside.     

Determination of Adrenaline by Atomic Absorption Spectrometry Using Copper as Probe Reagent in Pharmaceutical and Serum Samples

In this paper, an atomic absorption spectrometric method has been established to determine adrenaline using Cu(II) as probe reagent. In the presence of SCN^?, it has been demonstrated that Cu(II) is reduced to Cu(I) by adrenaline at pH 6.0, and the in situ formed Cu(I) reacts with SCN‐ to form the white emulsion of CuSCN. According to the amount of residual Cu(II) which is measured by atomic absorption spectrometry, the amount of adrenaline can be determined indirectly. Beer's law is obeyed in the range of adrenaline concentration of 0.080‐6.00 mg mL‐1, and the linear regression equation is A = 0.20342 ‐ 0.02756C (μg mL^?1) with a correlation coefficient of 0.9998. The detection limit is 0.033 μg mL^?1 and R.S.D. is 0.56%. This method has been successfully applied to determine adrenaline in pharmaceutical and serum samples with satisfactory results.     

Electrochemical fabrication and characterization of p-CuSCN/n-ZnO heterojunction devices

p-CuSCN/n-ZnO heterojunction devices were prepared by depositing CuSCN electrochemically over a ZnO film previously deposited. The compact and smooth surface films of n-ZnO on FTO substrate were deposited electrochemically from a nonaqueous bath. The CuSCN films were characterized by cyclic voltammetry, chronoamperometry, SEM, energy-dispersive X-ray spectroscopy, and XRD measurements. The pure crystalline films of CuSCN with intrinsic trigonal pyramidal morphology over the ZnO films were obtained electrochemically by fixing the SCN/Cu ratio in the electrolytic bath 1.5:1 at 60 °C with ?0.4 V deposition potential. Photocurrent measurements showed the increase of intrinsic surface states or defects in ZnO/CuSCN interface. The I–V characteristic of p-CuSCN/n-ZnO heterojunctions shows good rectification behavior with a rectification ratio of 250 at ±2 V. The value of 2.81 of the ideality factor calculated by fitting the semilogarithmic I–V data with the ideal diode equation revealed the better electrical contact between the smooth ZnO and CuSCN films than that of ZnO nano-rods and CuSCN crystallites.     

基于铜离子促水解反应高灵敏电化学检测鸡肉中头孢氨苄残留

利用纳米金( AuNPs)和L-半胱氨酸( Cys)修饰金电极( AuE),得到对Cu2+具有灵敏响应的电化学修饰电极( Cys/AuNPs/AuE)。在Cu2+存在时对头孢氨苄进行水解,通过方波伏安法测定水解液中剩余Cu2+的浓度,从而间接测得头孢氨苄的含量。对金电极的修饰条件、头孢氨苄的水解条件等进行了优化。在pH 4.5的HAc-NaAc缓冲液中,头孢氨苄在Cu2+存在时于沸水浴中水解25 min后,溶液中剩余Cu2+在Cys/AuNPs/AuE上有良好的电化学响应,还原峰电流差与头孢氨苄的浓度分别在0.0058~0.12μmol/L和0.12~2.9μmol/L范围内呈良好的线性关系,检出限为1.9 nmol/L(S/N=3)。用本方法对鸡肉样品中的头孢氨苄残留进行测定,结果表明,本方法简便快速、灵敏度高,适用于鸡肉等食品样品中头孢氨苄残留的测定。     

Syntheses of supramolecular CuCN complexes by decomposing CuSCN: a general route to CuCN coordination polymers?

The solvothermal reaction of CuSCN with 1,2-bis(diphenylphosphino)ethane (dppe) yielded a coordination polymer, which was characterized to be a complex of CuCN and 1,2-bis(diphenylthiophosphinyl)ethane (dppeS2): [(CuCN)2(dppeS2)]n (1). The identification of complex 1 reveals that CuSCN was decomposed and the sulfur was transferred to dppe, and represents a new example of the transformation of inorganic sulfur to organic sulfur. The weak coordination interactions between CuCN and dppeS2 indicate that dppeS2 may be substituted by ligands with strong coordination ability. The ligand 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tpt) was chosen as a substitute ligand. Three novel CuCN coordination polymers of tpt were synthesized and characterized: [Cu2(CN)2(tpt)]n (2) with a 3-D (10,3)-a network, [Cu2(CN)2(tpt)]n (3) and [Cu2(SCN)(CN)(tpt)]n (4) both with a 2-D (6,3) network, and only complex 2 can be obtained from CuCN directly. Interestingly, compounds 2 and 3 are genuine high-dimensional supramolecular isomers. During the syntheses of 2-4, single crystals of dppeS2 were isolated, which indicates it was substituted by tpt ligand and also confirmed the transformation of sulfur from CuSCN to dppe. The transformation of sulfur can be observed only when the temperature is relative high (>160 degrees C). At 140 degrees C, complex 5 containing only CuSCN was attained and no dppeS2 has been monitored in the resulting filtrate.     

Electrochemistry of the system Cu(II)Cu(I)Cu(0) in acidified thiocyanate solutions

The system Cu(II)Cu(I)Cu(0) in acidified thiocyanate medium was investigated at carbon, mercury, and copper amalgam electrodes using cyclic voltammetry, normal, differential and reverse pulse voltammetry, double potential step chronocoulometry, and exhaustive coulometry. Reduction of Cu(II) to Cu(I) on carbon electrodes proceeds quasireversibly. At moderate concentrations of Cu(II) and SCN^? the reduction of Cu(II) leads to three-dimensional precipitation of CuSCN which can be deposited at the electrode surface. At high concentration of SCN^? complexation dominates over precipitation and only soluble species are formed. At mercury and copper amalgam electrodes the situation is more complicated. The three- dimensional precipitation is preceded by strong thiocyanate-induced adsorption of Cu(I) which results in formation of a mono layer at potential well-separated from those where diffusing product is formed.     

N-苄基甘氨酸-N-乙基磷酸离解常数及其有关配合物稳定常数的确定

用 p H滴定法测定了标题化合物在 2 5± 0 .1℃、3 5± 0 .1℃和 4 5± 0 .1℃ KNO3 存在下的离解常数 ;计算了 2 5± 0 .1℃离解反应的焓变Δr Hm和熵变Δr Sm。确定了 2 5± 0 .1℃ KNO3 存在下 ,它与 Co( )、Ni( )及Cu( )形成的配合物的稳定常数     

From encapsulation to polypseudorotaxane: unusual anion networks driven by predesigned metal bis(terpyridine) complex cations

Solvothermal reactions of CuSCN, metal (Mn2+, Fe2+, Co2+, Ni2+, Cu2+) sulfate, and terpyridine (2,2':6',2' '-terpyridine or 4'-p-tolyl-2,2':6',2' '-terpyridine) in the presence of triphenylphosphine yielded a series of hybrid coordination compounds, in which in situ formed metal bis(terpyridine) complex cations are encapsulated by a 3D anionic network or entangled by 2D heartlike networks, forming encapsulation or polypseudorotaxane supramolecules. The complex cations play a role as template to direct the fabrication of the structures.     

在线流动注射螯合树脂预富集石英缝管增敏火焰原子吸收法测定水中痕量镉和铜

应用高效的在线流动注射螯合树脂预富集石英缝管增敏火焰原子吸收系统直接测定水中痕量镉和铜 ,试验用内装 2 0 0 mg Amberlite XAD- 4键合的 5-磺酸 - 8-羟基喹啉螯合树脂的锥形柱 ,在 p H6条件下 ,样品流速为 6.0 ml·min-1,90 s装样 ,用 0 .5mol· L-1HCl洗脱 ,分析速度为30样·h-1分别获得 38和 40倍的富集 ,经石英缝管增敏 ,总灵敏度分别提高 1 36和 1 2 0倍 ,检出限为 0 .1和 0 .2μg· L-1。对镉和铜含量分别为 2 .0 ,5.0μg· L-1的水样连续测定 1 1次的相对标准偏差分别为 2 .8%和 3.4% ,可直接测定水体中 μg· L-1级的镉和铜。     

A novel method for the spectrophotometric determination of cefradine by using sodium nitroprusside as chromogenic reagent

A novel method is developed for the determination of cefradine by using sodium nitroprusside as chromogenic reagent. The experiment indicates that a russety product is formed by the reaction of cefradine with sodium nitroprusside in basic solution, and the maximum absorption wavelength （λmax） of russety product is 505 rim. And the sensitization of tetradecyl benzyl dimethyl ammonium chloride for the reaction of cefradine with sodium nitroprusside is remarkable, The apparent molar absorption coefficient （5505） is 2.81 × 103 L/mol cm. The linear equation isA = 0.0657 ＋ 0.00804C （μg/mL） in the range of 1.50-55.0μg/mL of cefradine with a correlation coefficient r = 0.9992, and the detection limit is 1.38 p,g/mL. This method has been applied to determine cefradine in capsule and tablet samples.     

PAN胶束增溶光度法测定铝合金中铜

PAN是铜生成的配合物在水中溶解度很小。在水溶液中,PAN作显色剂作光度法测定铜时,常用表面活性剂增溶。已使用过的表面活性剂有非离子型^[1]和阴离子型^[2]。本文较详细地研究了在CTMAB存在下,铜（Ⅱ）与PAN的显色反应条件,并拟定了一种铝合金中铅测定的直接分光光度法。方法不需萃取,结果令人满意^[3,4]。