荧光动力学法测定唾液中痕量硫氰根

人体内的SCN-主要分布于人体体液及代谢物中,如唾液、血浆、尿液等。其来源主要有两种途径:一是烟草中氰化物的代谢产物,人体内硫氰酸盐的含量是区别吸烟者和不吸烟者的重要标志[1,2];二是某些食物的代谢产物,如卷心菜等。硫氰酸盐可作为药物用于治疗甲状腺疾病,但体液中SCN-含     

Kinetic Spectrophotometric Determination of Trace Amounts of Nitrite by Catalytic Reaction between Methylthymol Blue and Bromate

A kinetic spectrophotometric method for determination of trace nitrite in two dynamic ranges (2–100 and 100–500 ng/mL) based on its catalytic effect on the reaction between methylthymol blue and potassium bromate in acidic (sulfuric acid) media is described. The reaction was monitored spectrophotometrically by measuring the decreasing color of methylthymol blue at 437 nm by the fixed‐time method of 4.0 min at 30°C. The detection limit is 0.6 ng/mL, and the relative standard deviations for 50.0 and 250.0 ng/mL nitrite are 1.6% and 1.3%, respectively. The method was used for the determination of nitrite in water samples.     

动力学荧光光度法测定己烯雌酚

基于酸性介质中己烯雌酚对羟自由基与吖啶橙氧化还原反应的阻抑作用,建立了测定己烯雌酚的动力学荧光分析新方法。方法线性范围为0.1~50 ng/mL,检出限为0.03 ng/mL。     

吖啶橙指示荧光分析法测定双酚A

基于在酸性介质中,双酚A对羟自由基与吖啶橙的氧化还原反应的阻抑作用,建立了测定双酚A的荧光分析新方法.该方法简单,快速,线性范围为1.0～100 ng/mL,检出限为0.21 ng/mL.将其用于塑料制品中双酚A的测定,结果满意.     

Kinetic spectrophotometric determination of traces of iron(II)

A simple method for the selective and sensitive kinetic spectrophotometric determination of iron (II) is described. The method is based on the oxidation reaction of reduced phenolphthalein by periodate in alkaline media. The change in absorbance was measured using the fixed time method. The effect of different variables on the reaction was investigated and optimum conditions were obtained. The calibration curve was linear in the range 50–3000 ng/mL, and a detection limit of 17 ng/mL was obtained. The relative standard deviation of ten replicate determinations of 200 ng/mL of Fe(II) was 1.2%. The determination of Fe(II) in the presence of a 50-fold amount of Fe(III) could be carried out. This article was submitted by the authors in English.     

Catalytic determination of ultra trace amounts of palladium by linear sweep voltammetry

A sensitive method is proposed for the determination of palladium, based on its catalytic effect on the reduction of malachite green by hypophosphite. The reaction rate is monitored by measuring the current of product of reaction at −0.79 V vs. Ag/AgCl reference electrode. The linear dynamic range is 30.0–300.0 ng/mL with a limit of detection of 10.0 ng/mL. The interference effects of many ions were studied. The method was used for the determination of Pd(II) in synthetic samples of dental alloys with satisfactory results.     

Spectrophotometric determination of palladium(II) based on its catalytic effect on the reduction of azure I by sodium hypophosphite

A catalytic-spectrophotometric method for the determination of traces of palladium(II) is proposed. The reaction is based on the catalytic action of palladium(II) on the reduction of azure I (λ_max = 647 nm) by sodium hypophosphite. The various variables affecting the sensitivity were studied, and a study of interfering ions was also carried out. The reaction gave a detection limit of 4.3 ng/mL palladium(II) and good reproducibility with a relative standard deviation of 1.53–1.98% in the palladium(II) concentration range 40–200 ng/mL. The method yielded another linear range (5–40 ng/mL) when using slightly different conditions. In this case, the detection limit was 0.78 ng/mL palladium(II), and the relative standard deviation for ten replicate analyses of 20 ng/mL palladium(II) was 2.05%. The method was applied to the determination of palladium in a sample of activated charcoal. The text was submitted by the authors in English.     

Kinetic spectrophotometric method for the determination of selenium(IV) by its catalytic effect on the reduction of spadns by sulphide in micellar media

A simple kinetic spectrophotometric method was developed for the determination of ultratrace amounts of Se(IV). The method is based on the reduction of spadns by sulphide in micellar media. The reaction was monitored spectrophotometrically by measuring the decrease in the absorbance of spadns at 515 nm with a fixed-time method. The decrease in the absorbance of spadns is proportional to the concentration of Se(IV) in the range 0.5–100 ng/mL with a fixed time of 2.5–7.0 min from the initiation of the reaction. The limit of detection is 0.3 ng/mL Se(IV). The relative standard deviation for the determination of 0.02 and 0.10 μg/mL Se(IV) was 2.10 and 1.95%, respectively. The method was applied to the determination of Se(IV) in water. The text was submitted by the authors in English.     

Kinetic-Spectrophotometric Determination of Tellurium (IV) by Its Catalytic Effect on the Reduction of Thionine by Sodium Sulfide in Cationic Micellar Medium

A simple and highly sensitive method is proposed for the determination of Te(IV) by its catalytic effect on the reduction of thionine by sodium sulfide in the presence of cetyl trimethyl ammonium bromide as a micelle media. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of thionine at 600 nm with a fixed time of 0.5-2.5 min from initiation of the reaction. Tellurium can be measured in the concentration range of 0.6-500.0 ng/mL, with a limit of detection of 0.3 ng/mL Te(IV). The influence of more than thirty potential interfering ions was studied on the determination of tellurium. The relative standard deviation for ten replicate measurements of 0.020 and 50.0 ng/mL Te(IV) was 2.1 and 1.9%, respectively. The method was applied for the determination of tellurium in synthetic samples.     

光化学-荧光分析法研究(Ⅷ)——波长扫描-反应速差分析法

提出了波长扫描-光化学反应速差荧光分析同时测定双组分的方法,以核黄素的光分解反应和甲萘醌的光还原反应为例考察了方法的可行性.结果表明,核黄素、甲萘醌浓度分别在(0～1.20)μg/mL和(0～2.70)μg/mL范围内呈良好的线性关系(γ为0.999和0.998).检出限分别为0.22ng/mL和2.6ng/mL(n=11).平均回收率分别为101%、99%.     

Chemiluminescence Determination of Molybdenum by on-Line Reduction with a Flow Injection System

ThereactionsofLuwithhydrogenperoxidecatalysedbymetalionsandalsoreactionofLuwithorganicreductantssuchasglucoseandascorbicacidhavebeenreported"=.OurrecentstudiesshowedthatsomeinorganicreductantssuchasMo(Ill),V(11),U(ill),W(ill),Cr(II),Ti(ill)andFe(11)etc.canreactwithLuinstrongalkalinemediumtogenerateCL.Inthispaper,theCLreactionbetweenLuandMo(ill)producedbyaJonesreductor3hasbeenstudiedindetailforthefirsttime,andtheCLreactionhasbeensuccessfullyappliedtodeterminemolybdenumwithexcellentsensi…     

Determination of the antibacterial drug sulfamethoxazole in pharmaceutical preparations containing trimethoprim by spectrofluorimetry after derivatization with fluorescamine

An analytical method was developed for the determination of sulfamethoxazole (SMZ) in the presence of trimethoprim (TMP) by normal fluorescence. When both analytes are present a selective derivatization with fluorescamine of SMZ gives an intense fluorescent derivative with no interference from the other compound. The reaction was optimized to obtain the best analytical performance. The detection limit and the lower limit of quantitation of SMZ in the reaction medium was 5.2 ng/mL. The intra-day precision (relative standard deviation) was 1.51% for a 100 ng/mL SMZ standard solution and the inter-day precision over 7 days for a 100 ng/mL solution in the presence of 20 ng/mL TMP solution was 2.5%. The method has been applied to three pharmaceutical preparations containing both compounds, without any separation steps required.     

Determination of the antibacterial drug sulfamethoxazole in pharmaceutical preparations containing trimethoprim by spectrofluorimetry after derivatization with fluorescamine

An analytical method was developed for the determination of sulfamethoxazole (SMZ) in the presence of trimethoprim (TMP) by normal fluorescence. When both analytes are present a selective derivatization with fluorescamine of SMZ gives an intense fluorescent derivative with no interference from the other compound. The reaction was optimized to obtain the best analytical performance. The detection limit and the lower limit of quantitation of SMZ in the reaction medium was 5.2 ng/mL. The intra-day precision (relative standard deviation) was 1.51% for a 100 ng/mL SMZ standard solution and the inter-day precision over 7 days for a 100 ng/mL solution in the presence of 20 ng/mL TMP solution was 2.5%. The method has been applied to three pharmaceutical preparations containing both compounds, without any separation steps required. Received: 28 December 1998 / Revised: 28 April 1999 / Accepted: 30 April 1999     

Highly selective catalytic determination of ultra trace amounts of rhodium by linear sweep voltammetry

A highly selective and sensitive method is proposed for the determination of rhodium, based on the catalytic effect on the oxidation of Nile blue by periodate. The reaction rate is monitored by measuring the current of Nile blue at –0.37 V vs. Ag/AgCl reference electrode. The linear working range is 5 to 100 ng/mL with a limit of detection of 0.1 ng/mL. The interference effects of more than forty ions were studied. The method was used for the determination of Rh (III) in synthetic samples with satisfactory results.     

Kinetic spectrophotometric determination of trace amounts of selenium and vanadium

A sensitive kinetic spectrophotometric method has been developed for the determination of Se(IV) over the range of 45 to 4000 ng in 10 mL of solution. The method is based on the catalytic effect of Se(IV) on the reduction reaction of bromate by hydrazinium dichloride, with subsequent reaction of Ponceau S with products of the above reaction (chlorine and bromine), causing color changing of Ponceau S. Method development includes optimization of time interval for measurement of slope, pH, reagents concentration, and temperature. The optimized conditions yielded a theoretical detection limit of 33 ng/¶10 mL of solution of Se(IV). The interfering effects were studied and removed. The method was applied to the determination of selenium in spiked water, Kjeldahl tablet, selenium tablet, and shampoo. Vanadium(V) has an inhibition effect on the catalyzed reaction of bromate and hydrazine by selenium. Using this effect, V(V) can be determined in the range of 70 to 2500 ng in 10 mL of solution. The optimization procedure includes pH and selenium concentration. An extraction method was used for interference removal. The method was applied to the determination of vanadium in petroleum.     

Kinetic spectrophotometric determination of trace amounts of selenium and vanadium

A sensitive kinetic spectrophotometric method has been developed for the determination of Se(IV) over the range of 45 to 4000 ng in 10 mL of solution. The method is based on the catalytic effect of Se(IV) on the reduction reaction of bromate by hydrazinium dichloride, with subsequent reaction of Ponceau S with products of the above reaction (chlorine and bromine), causing color changing of Ponceau S. Method development includes optimization of time interval for measurement of slope, pH, reagents concentration, and temperature. The optimized conditions yielded a theoretical detection limit of 33 ng/?10 mL of solution of Se(IV). The interfering effects were studied and removed. The method was applied to the determination of selenium in spiked water, Kjeldahl tablet, selenium tablet, and shampoo. Vanadium(V) has an inhibition effect on the catalyzed reaction of bromate and hydrazine by selenium. Using this effect, V(V) can be determined in the range of 70 to 2500 ng in 10 mL of solution. The optimization procedure includes pH and selenium concentration. An extraction method was used for interference removal. The method was applied to the determination of vanadium in petroleum. Received: 20 October 1998 / Revised: 17 April 1999 / Accepted: 3 June 1999     

钴(Ⅱ)-过氧化氢-DCF 偶氮胂体系催化动力学光度法测定中草药中痕量钴

在邻苯二甲酸氢钾-氢氧化钠介质中,以钴(Ⅱ)催化过氧化氢氧化 DCF 偶氮胂的褪色反应为指示反应,建立了测定痕量钴(Ⅱ)的新方法。测定了反应级数和表面活化能。方法的检出限为 2.6×10-12 g/mL,线性范围为 0～23 ng/10mL。用于测定几种中草药样品中的钴,相对标准偏差为 2.8%～3.0%。     

铑-钨酸盐-罗丹明B缔合显色反应的研究及应用

在聚乙烯醇 (PVA)存在下 ,铑 ( )与钨酸盐及罗丹明 B(RB)形成的离子缔合物在 570 nm处产生最大吸收。建立了测定铑 ( )的光度分析方法 ,其表观摩尔吸光系数 ε达 1 0 7(L·mol-1·cm-1)数量级。方法的检测范围为 0～ 50ng/2 5m L ,检出下限为 0 .2 9ng/2 5m L。大量存在的常见离子对 Rh( )的测定不干扰。用此方法测定了催化剂及工业产品中铑的含量 ,结果与标准方法 (Sn Cl2法 )一致。     

溴酸钾二甲酚橙体系-顺序注射-催化光度法测定痕量钒

在酸性介质条件下,钒(Ⅳ)能显著催化溴酸钾对二甲酚橙的氧化褪色反应。据此建立了测定痕量钒(Ⅳ)的顺序注射催化光度法。方法的线性范围为0.5⁵0ng/mL、检出限为0.4ng/mL。对10ng/mL的钒(Ⅳ)连续11次测定的相对标准偏差为1.1%。用于环境水样中痕量钒(Ⅳ)的测定,加标回收率为91%50ng/mL、检出限为0.4ng/mL。对10ng/mL的钒(Ⅳ)连续11次测定的相对标准偏差为1.1%。用于环境水样中痕量钒(Ⅳ)的测定,加标回收率为91%¹08%。