Bioelectrochemically Triggered Apoferritin-based Bionanoreactors:Synthesis of CdSe Nanoparticles and Monitoring with Leaky Waveguides

Herein, we describe a novel method for producing cadmium-selenide nanoparticles (CdSe NPs) with controlled size using apoferritin as a bionanoreactor triggered by local pH change at the electrode/solution interface. Apoferritin is known for its reversible self-assembly at alkaline pH. The pH change is induced electrochemically by reducing O2 through the application of sufficiently negative voltages and bioelectrochemically through O2 reduction catalyzed by laccase, co-immobilized with apoferritin on the electrode surface. Specifically, a Ti electrode is modified with (3-Aminopropyl)triethoxysilane, followed by glutaraldehyde cross-linking (1.5% v/v in H2O) of apoferritin (as the bionanoreactor) and laccase (as the local pH change triggering system). This proposed platform offers a universal approach to controlling the synthesis of semiconductor NPs within a bionanoreactor solely driven by (bio)electrochemical inputs. The CdSe NPs obtained through different synthetic approaches, namely electrochemical and bioelectrochemical, were characterized spectroscopically (UV-Vis, Raman, XRD) and morphologically (TEM). Finally, we conducted online monitoring of CdSe NPs formation within the apoferritin core by integrating the electrochemical system with LWs. The quantity of CdSe NPs produced through bioelectrochemical means was determined to be 2.08 ± 0.12 mg after 90 minutes of voltage application in the presence of O2. TEM measurements revealed that the bioelectrochemically synthesized CdSe NPs have a diameter of 4 ± 1 nm, accounting for 85% of the size distribution, a result corroborated by XRD data. Further research is needed to explore the synthesis of nanoparticles using different biological nanoreactors, as the process can be challenging due to the elevated buffer capacitance of biological media

Bioelectrochemically Triggered Apoferritin-based Bionanoreactors:Synthesis of CdSe Nanoparticles and Monitoring with Leaky Waveguides

Herein, we describe a novel method for producing cadmium-selenide nanoparticles (CdSe NPs) with controlled size using apoferritin as a bionanoreactor triggered by local pH change at the electrode/solution interface. Apoferritin is known for its reversible self-assembly at alkaline pH. The pH change is induced electrochemically by reducing O2 through the application of sufficiently negative voltages and bioelectrochemically through O2 reduction catalyzed by laccase, co-immobilized with apoferritin on the electrode surface. Specifically, a Ti electrode is modified with (3-Aminopropyl)triethoxysilane, followed by glutaraldehyde cross-linking (1.5% v/v in H2O) of apoferritin (as the bionanoreactor) and laccase (as the local pH change triggering system). This proposed platform offers a universal approach to controlling the synthesis of semiconductor NPs within a bionanoreactor solely driven by (bio)electrochemical inputs. The CdSe NPs obtained through different synthetic approaches, namely electrochemical and bioelectrochemical, were characterized spectroscopically (UV-Vis, Raman, XRD) and morphologically (TEM). Finally, we conducted online monitoring of CdSe NPs formation within the apoferritin core by integrating the electrochemical system with LWs. The quantity of CdSe NPs produced through bioelectrochemical means was determined to be 2.08 ± 0.12 mg after 90 minutes of voltage application in the presence of O2. TEM measurements revealed that the bioelectrochemically synthesized CdSe NPs have a diameter of 4 ± 1 nm, accounting for 85% of the size distribution, a result corroborated by XRD data. Further research is needed to explore the synthesis of nanoparticles using different biological nanoreactors, as the process can be challenging due to the elevated buffer capacitance of biological media

Metal organic frameworks enhanced dispersive solid phase microextraction of malathion before detection by UHPLC-MS/MS

Metal organic frameworks are considered as an efficient and promised adsorbent for separation of several ions and compounds from solutions due to its unique geometric structure. Herein, copper-benzyl tricarboxylic acid based metal organic frameworks have showed a high efficiency in enrichment and microextraction of malathion from food and water samples. The microextraction procedures were followed by determination of malathion by ultra high performance liquid chromatography with tandem mass spectrometry. The optimum recoveries for malathion were obtained at pH 6, and with using 2 mL of ethyl acetate as the eluent. The microextraction procedures showed a detection limits and the quantification limits of 4.0 and 10.0 mu g/L, respectively. The intra- and interday precision showed a relative standard deviation% less than 10. The feasibility of the proposed procedure was determined by evaluating the addition/recovery studies of malathion from the real samples. The absolute recovery% was >= 92%. Furthermore, some ions were tested as cointerfering ions, and the recovery% was 93-100%. These results confirm that the developed microextraction procedure based on copper-benzyl tricarboxylic acid based metal organic frameworks as extractor for dispersive solid phase microextraction is matrix-independent, and can be applied for various real samples including different matrix or various malathion content

Metal organic frameworks enhanced dispersive solid phase microextraction of malathion before detection by UHPLC‐MS/MS

Metal organic frameworks are considered as an efficient and promised adsorbent for separation of several ions and compounds from solutions due to its unique geometric structure. Herein, copper-benzyl tricarboxylic acid based metal organic frameworks have showed a high efficiency in enrichment and microextraction of malathion from food and water samples. The microextraction procedures were followed by determination of malathion by ultra high performance liquid chromatography with tandem mass spectrometry. The optimum recoveries for malathion were obtained at pH 6, and with using 2 mL of ethyl acetate as the eluent. The microextraction procedures showed a detection limits and the quantification limits of 4.0 and 10.0 mu g/L, respectively. The intra- and interday precision showed a relative standard deviation% less than 10. The feasibility of the proposed procedure was determined by evaluating the addition/recovery studies of malathion from the real samples. The absolute recovery% was >= 92%. Furthermore, some ions were tested as cointerfering ions, and the recovery% was 93-100%. These results confirm that the developed microextraction procedure based on copper-benzyl tricarboxylic acid based metal organic frameworks as extractor for dispersive solid phase microextraction is matrix-independent, and can be applied for various real samples including different matrix or various malathion content

Metal Organic Framework-Based Dispersive Solid-Phase Microextraction of Carbaryl from Food and Water Prior to Detection by Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry

In this work, metal organic frameworks (A100 Al-based MOFs) were used in dispersive solid-phase microextraction (DSPME) for the isolation and preconcentration of the carbaryl from vegetable, fruit and water samples. The A100 Al-based MOFs showed excellent behavior for the adsorption of carbaryl from a water-ethanol solution; additionally, carbaryl was easily desorbed with ethyl acetate for detection by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-TMS). The analytical process of DSPME together with UPLC-TMS provides the accurate monitoring of trace carbaryl residues. The results show that the optimal recovery% of carbaryl was obtained at a sample apparent pH of 5, with the application of 1 mL of ethyl acetate to elute the carbaryl from the A100 Al-based MOFs. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.01 mg.L-1 and 0.03 mg.L-1, respectively. The RSD% was 0.8-1.9, and the preconcentration factor was 45. DSPME and UPLC-TMS were successfully used for the isolation and detection of carbaryl in food and water samples

Development of combined-supramolecular microextraction with ultra-performance liquid chromatography-tandem mass spectrometry procedures for ultra-trace analysis of carbaryl in water, fruits and vegetables

For the fast and selective preconcentration-separation of carbaryl from environmental samples, a simple and cheap supramolecular solvent microextraction method (Ss-ME) has been applied with ultra-performance liquid chromatography-tandem mass spectrometry. Various analytical parameters that have a noticeable effect on the extraction of carbaryl by supramolecular liquid phase microextraction were optimised by selecting the peak area as the response. The parameters including pH of solution, type and volume of supramolecular formula, matrix effect and the sample volume were optimised. The quantitative recoveries were obtained between pH 2.0 and 4.0 of sample solution phase by using a supramolecular phase consist of heptanol and tetrahydrofuran. The limit of detection and limit of quantification were 0.03 mg L-1 and 0.09 mg L-1 respectively. The relative standard deviation was 7.11 and the preconcentration factor was 15. The microextraction procedure for trace carbaryl was used for various samples such as fruits, vegetables and water samples with the recovery% range between 90% and 102%

Supramolecular solvent microextraction and ultra-performance liquid chromatography-tandem mass spectrometry combination for the preconcentration and determination of malathion in environmental samples

A supramolecular solvent microextraction method was used for the fast and selective preconcentration separation of malathion, and then ultra-performance liquid chromatography-tandem mass spectrometry was applied for the detection of malathion. The supramolecular solvent is a suitable medium for malathion collection from the sample extract. The results showed that the quantitative recovery of malathion was obtained at pH 4 with heptanol-tetrahydrofuran as the supramolecular solvent. The preconcentration of malathion by the developed microextraction method was established within 10 min. The limit of detection and the quantification limit were 1.4 and 4.2 mu g/L, respectively. A preconcentration factor of 40 was obtained, and the relative standard deviation was <7%. The developed supramolecular solvent microextraction method was applied for different real samples, including fruits, vegetables, and water samples