Optical Sensors for the Determination of Heavy Metal Ions

Diese Arbeit beschreibt die Entwicklung optischer Sensoren für die Bestimmung von Schwermetallionen in wässrigem Milieu. Ein Sensorprinzip für die selektive Bestimmung von Kupfer(II) basierend auf der Messung von Fluoreszenzintensitäten wird vorgestellt. Dieses wird anschließend durch eine Referenzierungsmethode optimiert. Ferner wird ein neues Sensorprinzip im Mikrotiterplattenformat für die gleichzeitige Bestimmung mehrerer Ionen mit Hilfe von bildgebenden Verfahren präsentiert

Supramolecular Luminescent Sensors

There is great need for stand-alone luminescence-based chemosensors that exemplify selectivity, sensitivity, and applicability and that overcome the challenges that arise from complex, real-world media. Discussed herein are recent developments toward these goals in the field of supramolecular luminescent chemosensors, including macrocycles, polymers, and nanomaterials. Specific focus is placed on the development of new macrocycle hosts since 2010, coupled with considerations of the underlying principles of supramolecular chemistry as well as analytes of interest and common luminophores. State-of-the-art developments in the fields of polymer and nanomaterial sensors are also examined, and some remaining unsolved challenges in the area of chemosensors are discussed

Development of a Hybrid Multi-Functional Adsorbent-Solar-Photocatalyst for Detecting and Removing Toxic Heavy Metals and Refractory Pollutants from Water/Wastewater

In this thesis, treating portable water from hazardous pollutants such as dyes were studied by preparing TiO2/ZSM-5 mesoporous and modified RGO/TiO2/ZSM-5 mesoporous. Additionally, novel optical conjugated mesoporous adsorbents were prepared to treat portable water from heavy metal ions such as Hg2+ and Pb2+. Results show significant improvement over previous efforts by researchers. The work presented here has profound implications for future studies of wastewater treatment, and may one day help solve the problem of water scarcity

Desenvolvimento de eletrodos compósitos modificados com a resina de troca catiônica (Amberlite IR120) para determinação não-enzimática da glicose e do pesticida carbendazim

Orientador: Prof. Dr. Luiz Humberto Marcolino-JúniorCoorientador: Prof. Dr. Márcio Fernando BergaminiTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Química. Defesa : Curitiba, 27/09/2018Inclui referências: p. 84-94Resumo: A determinação da glicose por sensores eletroquímicos é amplamente investigada, devido à sua importância no cenário mundial, principalmente pelo aumento do número de pacientes com diabetes mellitus. Atualmente, busca-se novos materiais não-biológicos capazes de oxidar glicose com boa resposta eletroquímica, como o Cu (III), que possui alta atividade eletrocatalítica. No presente trabalho, foram imobilizados íons cobre em resina de troca catiônica (Amberlite IR 120H) e usados para criar o eletrodo compósito (ECR-Cu) para quantificar a glicose. O eletrodo compósito apresentou boa precisão e exatidão, exibindo uma faixa linear de trabalho de 5,0 ?mol L-1 a 1,0 mmol L-1 e um limite de detecção (LD) de 1,8 ?mol L-1. O sensor foi aplicado na determinação de glicose no sangue humano, sem interferência na sensibilidade por espécies eletroativas presentes no sangue, com recuperação ou 100-108%. A resina de troca catiônica (Amberlite IR 120H) também pode ser usada para pré-concentração de cátions orgânicos, como o carbendazim, não apenas como uma fase suporte. O carbendazim é um fungicida empregado em diversas culturas agrícolas, como a manga. O eletrodo composto de resina (ECR) foi aplicado para determinar este fungicida, e parâmetros relacionados como quantidade de resina utilizada na composição do eletrodo composto, pH e tempo de incorporação, parâmetros instrumentais foram estudados. Sob condições otimizadas, uma curva analítica foi obtida para a determinação de carbendazim empregando RCE que apresentou uma faixa de resposta linear entre 80,0 nmol L-1 a 2,0 ?mol L-1, com LD de 19 nmol L-1 calculado. Estudos de adição e recuperação de sucos de frutos de manga enriquecidos com analito foram realizados, resultando em recuperações que variaram de 97 a 99% das amostras de suco.Abstract: ABSTRACT Determination of glucose by an electrochemical sensor, is widely research due to its importance on the world stage, mainly by the increasing number of patients with diabetes mellitus. Currently, hunt up non-biological materials that can oxidize glucose with good electrochemical response, such as Cu (III) which has a high electrocatalytic activity. In the present work, it was immobilized copper ions in a cation exchange resin (Amberlite IR 120H) and used to create a composite electrode RCE-Cu to quantification of glucose. The composite electrode showed a good accuracy and robustness, exhibit a linear dynamic range of 5.0 ?mol L-1 to 1.0 mmol L-1, and a limit of detection (LOD) of 1.8 ?mol L-1. The sensor was applied in determination of glucose in human blood, without interference nor sensitivity affected by species present in blood, with recovery of 100-108%. The cation exchange resin (Amberlite IR 120H) can be used to preconcentration of organic cations, like carbendazim, not just as support phase. Carbendazim is a fungicide employed in several agricultural culture, like mango. A resin composite electrode (RCE) was applied to determinate this fungicide, related parameters such as amount of resin used in the composition of the composite electrode, pH and incorporation time, instrumental parameters was studied. Under optimized conditions, an analytical curve was obtained for the determination of carbendazim employing RCE, which showed a linear response range between 80,0 nmol L-1 to 2.0 ?mol L-1, with LOD of 19 nmol L-1. Studies of addition and recovery in mango fruit juice spiked with analyte were performed, yielding recoveries ranging from 97-99% of juice samples

Determination of Cadmium in Brown Rice Samples by Fluorescence Spectroscopy Using a Fluoroionophore after Purification of Cadmium by Anion Exchange Resin

Simple analytical methods are needed for determining the cadmium (Cd) content of brown rice samples. In the present study, we developed a new analytical procedure consisting of the digestion of rice using HCl, Cd purification using anion exchange resin, and then determining the Cd content using fluorescence spectroscopy. Digestion with 0.1 M HCl for 10 min at room temperature was sufficient to extract Cd from the ground rice samples. The Cd in the extract was successfully purified in preference to other metals using Dowex 1X8 chloride form resin. Low concentrations of Cd in the eluate could be determined using fluorescence spectroscopy with a fluoroionophore. Overall, the actual limit of quantification value for the Cd content in rice was about 0.1 mg-Cd/kg-rice, which was sufficiently low compared with the regulatory value (0.4 mg-Cd/kg-rice) given by the Codex Alimentarius Commission. We analyzed authentic brown rice samples using our new analytical procedure and the results agreed well with those determined using inductively coupled plasma optical emission spectrometry (ICP-OES). Since the fluoroionophore recognized Zn2+ and Hg2+ as well as Cd2+, a sample containing high concentration of Zn2+ or Hg2+ might cause a false positive result

Determination of Cadmium in Brown Rice Samples by Fluorescence Spectroscopy Using a Fluoroionophore after Purification of Cadmium by Anion Exchange Resin

Simple analytical methods are needed for determining the cadmium (Cd) content of brown rice samples. In the present study, we developed a new analytical procedure consisting of the digestion of rice using HCl, Cd purification using anion exchange resin, and then determining the Cd content using fluorescence spectroscopy. Digestion with 0.1 M HCl for 10 min at room temperature was sufficient to extract Cd from the ground rice samples. The Cd in the extract was successfully purified in preference to other metals using Dowex 1X8 chloride form resin. Low concentrations of Cd in the eluate could be determined using fluorescence spectroscopy with a fluoroionophore. Overall, the actual limit of quantification value for the Cd content in rice was about 0.1 mg-Cd/kg-rice, which was sufficiently low compared with the regulatory value (0.4 mg-Cd/kg-rice) given by the Codex Alimentarius Commission. We analyzed authentic brown rice samples using our new analytical procedure and the results agreed well with those determined using inductively coupled plasma optical emission spectrometry (ICP-OES). Since the fluoroionophore recognized Zn2+ and Hg2+ as well as Cd2+, a sample containing high concentration of Zn2+ or Hg2+ might cause a false positive result