A clean method for flow injection spectrophotometric determination of cyclamate in table sweeteners

A flow system based on the multicommutation is proposed for fast and clean determination of cyclamate. The procedure exploits the reaction of cyclamate with nitrite in acidic medium and the spectrophotometric determination of the excess of nitrite by iodometry. The flow system was designed with a set of solenoid micro-pumps to minimize reagent consumption and waste generation. The detection limit was estimated as 30 μmol L⁻¹ (99.7% confidence level) with linear response ranging up to 3.0 mmol L⁻¹. The coefficient of variation was estimated as 1.7% for a solution containing 2.0 mmol L⁻¹ cyclamate (n = 20). About 60 samples can be analyzed per hour, consuming only 3 mg KI and 1.3 μg NaNO₂, and generating 2.0 mL of effluent per determination, thus providing an environmentally friendly alternative to previously proposed procedures. Common artificial and natural sweeteners did not interfere when present in concentrations 10-times higher than cyclamate. The procedure was successfully applied for determination of cyclamate in artificial table sweeteners with results in agreement with the reference method at the 95% confidence level.     

流动注射协同化学发光法测定盐酸多巴胺

基于在碱性介质中,盐酸多巴胺和单宁协同促进KIO4氧化鲁米诺反应而产生发光,建立了流动注射化学发光法测定盐酸多巴胺的新方法。该方法测定盐酸多巴胺的线性范围为2.0×10-10～6.0×10-8g/mL,检出限为1.17×10-10g/mL,对于8.0×10-10g/mL盐酸多巴胺测定11次的相对标准偏差为1.92%。方法可应用于盐酸多巴胺注射液和尿样中盐酸多巴胺的测定。     

Pt NPs catalyzed chemiluminescence method for Hg2+ detection based on a flow injection system

Establishing a simple and accurate method for Hg²⁺ detection is of great importance for the environment and human health. In this work, platinum nanoparticles (Pt NPs) with different capped agents and morphologies were synthesized. It was found that Pt NPs exhibited peroxidase‐like activity that can catalyze the chemiluminescence (CL) of the luminol system without H₂O₂. The most intensive CL signals were obtained by using PVP‐capped Pt NPs as catalysis. Based on the fact that Hg²⁺ could further enhance the CL intensity in the Pt NPs‐luminol CL system, a Pt NPs‐catalyzed CL method based on a flow injection system is developed for the sensitive analysis of Hg²⁺. When the concentration of Hg²⁺ in the system increases, the CL intensity would together increase, thereby achieving sensitive Hg²⁺ detection. The limit of detection (LOD) was calculated to be 8.6 nM. This developed method provides a simple and rapid approach for the sensitive detection of Hg²⁺ and shows great promise for applications in other complex systems.     

流动注射阻抑化学发光法测定己烯雌酚

基于在碱性介质中,己烯雌酚对N-溴代丁二酰亚胺-鲁米诺化学发光体系的阻抑作用,建立了测定己烯雌酚的流动注射化学发光分析新方法,探讨并优化了流动注射化学发光的分析条件。该方法测定己烯雌酚的线性范围为1.5×10-8~2.6×10-7g/mL,检出限为5.0×10-9g/mL,对1.0×10-7g/mL的己烯雌酚标准溶液进行11次测定,相对标准偏差为2.6%。并应用于饲料、己烯雌酚片剂中的己烯雌酚的测定。     

流动注射化学发光法测定褪黑素

在强碱性介质中,铁氰化钾可直接氧化褪黑素产生化学发光。基于此,建立了一种测定褪黑素的流动注射化学发光分析方法。线性范围为1.9×10-6~2.3×10-4g/mL,检出限为5×10-7g/mL,该法已用于药物中褪黑素的测定。     

Flow injection chemiluminescence analysis of phenolic compounds using the NCS-luminol system

A flow injection system coupled with two simple and sensitive chemiluminescence (CL) methods is described for the determination of some phenolic compounds. The methods are based on the inhibition effects of the investigated phenols on the CL signal intensities of N-chlorosuccinimide-KI-luminol (NCS-KI-luminol) and NCS-luminol systems. The influences of the chemical and hydrodynamic parameters on the decrease in CL signal intensities of NCS-KI-luminol and NCS-luminol systems for hydroquinone, catechol, and resorcinol, serving as the model compounds of analyte, were studied in the flow injection mode of analysis. Under the selected conditions, the proposed CL systems were used for the determination of some phenolic compound and analytical characteristics of the systems including calibration equation, correlation coefficient, linear dynamic range, limit of detection, and sample throughput. The limits of detection for hydroquinone, catechol, and resorcinol were 0.002, 0.01, and 0.3 μM using the NCS-KI-luminol system; for the NCS-luminol system these were 0.01, 0.17, and 1.6 μM, respectively. The relative standard deviation for 10 repeated measurements of 0.04, 0.06, and 1 μM of hydroquinone, catechol, and resorcinol were 1.9, 1.4, and 2.0%, respectively, with the NCS-KI-luminol system; for 0.2, 0.5, and 4 μM of hydroquinone, catechol, and resorcinol these were 2.6, 2.2, and 3.7%, respectively, using the NCS-luminol system. The method was applied to the determination of catechol in known environmental water samples with a relative error of less than 6%. A possible reaction mechanism of the proposed CL system is discussed briefly.      

Flow injection chemiluminescence determination of isoniazid using luminol and silver nanoparticles

The effect of silver colloidal nanoparticles (AgNPs) on the luminol–isoniazid system was investigated. It was found that AgNPs could act as a nanocatalyst on the luminol–isoniazid system to generate chemiluminescence (CL). The CL emission spectrum of the luminol–isoniazid–AgNPs system showed a peak with a maximum at 425 nm. It was suggested that the luminophor species was the excited state 3-aminophthalate. The reduction of dissolved O₂ to H₂O₂ by isoniazid and decomposition of H₂O₂ to the oxygen-related radicals were attributed to the catalytic effect of AgNPs. Under optimized conditions, the CL signal intensity was linear with the isoniazid concentration in the range of 10–1000 ng mL^{− 1}, with the correlation coefficient of 0.9996. The limit of detection was 2.7 ng mL^{− 1} isoniazid. The relative standard deviations for seven repeated measurements of 60 and 200 ng mL^{− 1} isoniazid were 1.4 and 2.4%, respectively. The effect of potent interfering compounds on the CL signal intensity of the proposed luminol–isoniazid–AgNPs system was investigated. The proposed method was successfully applied to the determination of isoniazid in a pharmaceutical sample.     

流动注射化学发光法测定DL-酪氨酸

在甲醛存在下 ,高锰酸钾与DL 酪氨酸能够发生化学发光反应 ,产生很强的化学发光。据此采用流动注射技术 ,建立了一种测定DL 酪氨酸的化学发光分析法。方法的检出限为 2 .9× 1 0 - 8g/mL ,相对标准偏差为 1 .5 % ( 1 .0× 1 0 - 6g/mLDL 酪氨酸 ,n =1 1 ) ,线性范围为 1 .0× 1 0 - 7g/mL～ 5 .0× 1 0 - 6g/mL。     

快速化学发光联用流动注射技术测定西咪替丁

在NaOH-NaHCO3介质中,铁氰化钾氧化西咪替丁产生快速化学发光反应,0.5 s后发光达到最大,2 s后迅速衰减至零。本文结合流动注射技术,建立了一种化学发光测定西咪替丁的新方法。针对这一快速发光反应,设计了与之相应的管路系统和最短的反应管道来捕捉最大化学发光信号,发光强度与西咪替丁质量浓度在5×10-7~1×10-4g/mL范围内呈线性关系,检出限为1.1×10-7g/mL。对5×10-6g/mL西咪替丁进行11次平行测定,相对标准偏差为1.8%。本法已用于西咪替丁片剂的测定。     

流动注射化学发光法测定甲氧氯普胺

在酸性条件下，甲醛对高锰酸钾氧化甲氧氯普胺的化学发光反应有很强的增敏作用，据此，建立了流动注射化学发光法测定甲氧氯普胺纳新方法。方法的线性范围为0．4-100μg/mL，检出限为0．2μg/mL，对10μg/mL的甲氧氯普胺标准溶液连续11次测定的相对标准偏差为1．8％。方法已用于药物中甲氧氯普胺含量的测定。     

流动注射化学发光法测定甲硝唑

在碱性条件下 ,铁氰化钾氧化鲁米诺产生化学发光 ,甲硝唑对该体系有显著的增强作用 (亚铁氰化钾存在时 )。基于此 ,建立了流动注射化学发光测定痕量甲硝唑的新方法。甲硝唑浓度在 2 .0× 1 0 -6～ 4 .0× 1 0 -4 mol L范围内与发光强度呈良好的线性关系 ;检出限 (3σ)为 1 .5× 1 0 -7mol L。相对标准偏差 (c =1 .0× 1 0 -5mol L ,n=1 1 )为 3.6 %。方法已用于制剂中甲硝唑含量测定     

流动注射-化学发光法测定决明子蒽醌类化合物

基于在碱性条件下,蒽醌对ClO- Luminol化学发光体系的显著抑制作用,结合反向流动注射技术,提出了蒽醌的流动注射 化学发光分析新方法。蒽醌的质量浓度在0.5～100μg mL范围内与化学发光的抑制强度呈良好的线性关系。检出限为0.05μg mL,RSD=1.6%,采样频率为150次 h,回收率为105%～107.5%。     

流动注射阻抑化学发光法测定环境水中的酚

A new flow injection chemiluminesenet method was presented for the determination of phenol based on the inhibition effect of trace phenol on the chemiluminescence reaction between luminol and N-chlorosuccinimide system.The linear range for the determination of phenol is 1.5×10~(-5)~3.5×10~(-4)mg/mL,the detection limit is 2.36×10~(-6)mg/mL.This method has been used for the determination of phenol in water samples with satisfactory results.The mechanism of the inhibitory reaction was also discussed.     

A flow injection procedure based on solenoid micro-pumps for spectrophotometric determination of free glycerol in biodiesel

A flow system designed with solenoid micro-pumps is proposed for fast and greener spectrophotometric determination of free glycerol in biodiesel. Glycerol was extracted from samples without using organic solvents. The determination involves glycerol oxidation by periodate, yielding formaldehyde followed by formation of the colored (3,5-diacetil-1,4-dihidrolutidine) product upon reaction with acetylacetone. The coefficient of variation, sampling rate and detection limit were estimated as 1.5% (20.0 mg L⁻¹ glycerol, n = 10), 34 h⁻¹, and 1.0 mg L⁻¹ (99.7% confidence level), respectively. A linear response was observed from 5 to 50 mg L⁻¹, with reagent consumption estimated as 345 μg of KIO₄ and 15 mg of acetylacetone per determination. The procedure was successfully applied to the analysis of biodiesel samples and the results agreed with the batch reference method at the 95% confidence level.     

流动注射化学发光法测定茶饮料中的茶多酚

在碱性条件下,茶多酚对鲁米诺-KMnO4化学发光体系具有较强的抑制作用,据此建立了茶多酚的流动注射化学发光测定法。该法的化学发光抑制值ΔICL与茶多酚质量浓度在2.0×10-6~5.0×10-4mg/mL范围内,呈现出良好的线性关系,检出限为1.2×10-7mg/mL,对1.0×10-5mg/mL茶多酚测定的相对标准偏差为2.9%(n=11)。用于茶饮料中茶多酚的测定。     

流动注射化学发光法测定痕量NO_2~-的研究与应用

Based on the principle of the reaction of NO2-with I-and formation of I2 in HCl solution,and the chemiluminescence(CL) reaction between luminol and I2 in an alkaline medium.A fairly sensitive,simple and rapid flow-injection analysis-chemiluminescence method for the determina-tion of trace nitrite with the luminal-I——NO2-coupling luminescence system has been developed.Experiment conditions of flow-injection analysis are optimized.When satisfying the condition that Luminol as 4.0×10-4 mol/L,0.7 % KI,0.04 mol/...     

流动注射化学发光法测定己烯雌酚

基于己烯雌酚对鲁米诺与高碘酸钾在碱性介质中反应产生的化学发光信号有较强的增敏作用,建立了测定己烯雌酚的流动注射化学发光分析法。己烯雌酚质量浓度在13．4—1340μg／L范围内与化学发光强度呈良好的线性关系,检出限（3d）为4μg／L;对26．8μg／L己烯雌酚进行11次平行测定,相对标准偏差（RSD）为1．4％。该法已用于药物制剂中己烯雌酚的测定。     

Sensitive and selective determination of molybdenum by flow injection chemiluminescence method combined with controlled potential electrolysis technique

A sensitive and selective flow injection chemiluminescence (CL) method combined with controlled potential electrolysis technique was described for the determination of molybdenum. The method is based on the chemiluminescence reaction of luminol with unstable molybdenum(III) in alkaline solution. The molybdenum(III) was on-line reduced from molybdenum(VI) via controlled potential electrolysis technique using a homemade flow-through carbon electrolytic cell at the potential of −0.6 V (versus Ag/AgCl). The method allows the determination of molybdenum in the 5.0×10⁻¹⁰ to 5.0×10⁻⁷ g ml⁻¹ range with a limit of detection (3σ) of 5×10⁻¹¹ g ml⁻¹ molybdenum. The relative standard deviation is 2.6% for the 1.0×10⁻⁹ g ml⁻¹ molybdenum solution in 11 repeated measurements. This method was successfully applied to the determination of molybdenum in water samples.     

鲁米诺-铁氰化钾流动注射化学发光法测定头孢拉定

在碱性介质中,铁氰化钾氧化鲁米诺产生化学发光,头孢拉定对该体系有显著的增强作用。基于此并结合流动注射技术建立了测定头孢拉定含量的化学发光新方法。该法线性范围为0.16~160 mg/L,检出限为0.028 mg/L;对80 mg/L的头孢拉定进行平行测定11次,其相对标准偏差为0.99%。用本法对胶囊中头孢拉定进行测定,并初步探讨了该化学发光的反应机理。     

流动注射化学发光法测定阿莫西林

在碱性介质中 ,阿莫西林抗生素对鲁米诺 KMnO4化学发光反应有增敏作用 ,据此建立了微量快速测定阿莫西林的流动注射化学发光分析法。该法线性范围为 1 .0× 1 0 -7～ 5 .0× 1 0 -5g mL ,检出限为 3.0× 1 0 -8g mL ;对 1 .0× 1 0 -6g mL阿莫西林 1 1次平行测定 ,其相对标准偏差为 1 .7%。此法已用于阿莫西林胶囊中阿莫西林的测定。