Electrocatalytic Oxidation of Sulfur Containing Amino Acids at Renewable Ni‐Powder Doped Carbon Ceramic Electrode: Application to Amperometric Detection L‐Cystine,L‐Cysteine and L‐Methionine

A sol‐gel technique was used here to prepare a renewable carbon ceramic electrode modified with nickel powder. Cyclic voltammograms of the resulting modified electrode show stable and a well defined redox couple due to Ni(II)/Ni(III) system with surface confined characteristics. The modified electrode shows excellent catalytic activity toward L ‐cystine, L ‐cysteine and L ‐methionine oxidation at reduced overpotential in alkaline solutions. In addition the antifouling properties at the modified electrode toward the above analytes and their oxidation products increases the reproducibility of results. L ‐cystine, L ‐cysteine and L ‐methionine were determined chronoamperometricaly at the surface of this modified electrode at pH range 9–13. Under the optimized conditions the calibration curves are linear in the concentration range 1–450 μM, 2–90 μM and 0.2–75 μM for L ‐cystine, L ‐methionine and L ‐cysteine determination, respectively. The detection limit and sensitivity were 0.64 μM, 3.8 nA/ μM for L ‐cystine, 2 μM, 5.6 nA/ μM for L ‐methionine and 0.2 μM and 8.1 nA/μM for L ‐cysteine. The advantageous of this modified electrode is high response, good stability and reproducibility, excellent catalytic activity for oxidation inert molecules at reduced overpotential and possibility of regeneration of the electrode surface by potential cycling for 5 minutes. Furthermore, the modified electrode has been prepared without using specific reagents. This sensor can be used as an amperometric detector for disulfides detection in chromatographic or flow systems.     

Metal‐Ion Metathesis in Metal–Organic Frameworks: A Synthetic Route to New Metal–Organic Frameworks

A porous metal–organic framework, Mn(H₃O)[(Mn₄Cl)₃(hmtt)₈] (POST‐65), was prepared by the reaction of 5,5′,10,10′,15,15′‐hexamethyltruxene‐2,7,12‐tricarboxylic acid (H₃hmtt) with MnCl₂ under solvothermal conditions. POST‐65(Mn) was subjected to post‐synthetic modification with Fe, Co, Ni, and Cu according to an ion‐exchange method that resulted in the formation of three isomorphous frameworks, POST‐65(Co/Ni/Cu), as well as a new framework, POST‐65(Fe). The ion‐exchanged samples could not be prepared by regular solvothermal reactions. The complete exchange of the metal ions and retention of the framework structure were verified by inductively coupled plasma–atomic emission spectrometry (ICP‐AES), powder X‐ray diffraction (PXRD), and Brunauer–Emmett–Teller (BET) surface‐area analysis. Single‐crystal X‐ray diffractions studies revealed a single‐crystal‐to‐single‐crystal (SCSC)‐transformation nature of the ion‐exchange process. Hydrogen‐sorption and magnetization measurements showed metal‐specific properties of POST‐65.     

Metal–organic framework UiO‐67‐coated fiber for the solid‐phase microextraction of nitrobenzene compounds from water

A sol–gel coating technique was applied for the preparation of a solid‐phase microextraction fiber by coating the metal–organic framework UiO‐67 onto a stainless‐steel wire. The prepared fiber was explored for the headspace solid‐phase microextraction of five nitrobenzene compounds from water samples before gas chromatography with mass spectrometric detection. The effects of the extraction temperature, extraction time, sample solution volume, salt addition, and desorption conditions on the extraction efficiency were optimized. Under the optimal conditions, the linearity was observed in the range of 0.015–12.0 μg/L for the compounds in water samples, with the correlation coefficients (r) of 0.9945–0.9987. The limits of detection of the method were 5.0–10.0 ng/L, and the recoveries of the analytes from spiked water samples for the method were in the range of 74.0–102.0%. The precision for the measurements, expressed as the relative standard deviation, was less than 11.9%.     

Electronic and magnetic properties of all 3d transition‐metal‐doped ZnO monolayers

Stable geometries, electronic structures, and magnetic properties of the ZnO monolayer doped with 3d transition‐metal (TM) (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) atoms substituting the cation Zn have been investigated using first‐principles pseudopotential plane wave method within density functional theory (DFT). It is found that these nine atomic species can be effectively doped in the ZnO monolayer with formation energies ranging from ?6.319 to ?0.132 eV. Furthermore, electronic structures and magnetic properties of ZnO monolayer can be modified by such doping. The results show that the doping of Cr, Mn, Fe, Co, Ni, and Cu atoms can induce magnetization, while no magnetism is observed when Sc, Ti, and V atoms are doped into the ZnO monolayer. The magnetic moment is mainly due to the strong p–d mixing of O and TM (Cr, Mn, Fe, Co, Ni, and Cu) orbitals. These results are potentially useful for spintronic applications and the development of magnetic nanostructures. © 2013 Wiley Periodicals, Inc.     

Solid‐phase microextraction with a graphene‐composite‐coated fiber coupled with GC for the determination of some halogenated aromatic hydrocarbons in water samples

In this work, a graphene composite was coated onto etched stainless‐steel wire through a sol–gel technique and it was used as a solid‐phase microextraction (SPME) fiber. The prepared fiber was characterized by SEM, which revealed that the fiber had a highly porous structure. The application of the fiber was evaluated through the headspace SPME of five halogenated aromatic hydrocarbons (chlorobenzene, bromobenzene, 1,3‐dichlorobenzene, 1,2‐dichlorobenzene, and 1,2,4‐trichlorobenzene) in water samples followed by GC with flame ionization detection. The main factors influencing the extraction efficiency, including headspace volume, extraction time, extraction temperature, stirring rate, ionic strength of sample solution, and desorption conditions, were studied and optimized. Under the optimum conditions, the linearity of the method ranged from 2.5 to 800.0 μg/L for 1,2,4‐trichlorobenzene and from 2.5 to 500.0 μg/L for chlorobenzene, bromobenzene, 1,3‐dichlorobenzene, and 1,2‐dichlorobenzene, with the correlation coefficients (r) ranging from 0.9962 to 0.9980, respectively. The LODs (S/N = 3) of the method for the analytes were in the range between 0.5 and 1.0 μg/L. The recoveries of the method for the analytes obtained for the spiked water samples at 50.0 and 250.0 μg/L were from 76.0 to 104.0%.     

Hierarchical,Titania‐Coated,Carbon Nanofibrous Material Derived from a Natural Cellulosic Substance

Hierarchical, titania‐coated, nanofibrous, carbon hybrid materials were fabricated by employing natural cellulosic substances (commercial filter paper) as a scaffold and carbon precursor. Ultrathin titania films were firstly deposited by means of a surface sol–gel process to coat each nanofiber in the filter paper, and successive calcination treatment under nitrogen atmosphere yielded the titania–carbon composite possessing the hierarchical morphologies and structures of the initial paper. The ultrathin titania coating hindered the coalescence effect of the carbon species that formed during the carbonization process of cellulose, and the original cellulose nanofibers were converted into porous carbon nanofibers (diameters from tens to hundreds of nanometers, with 3–6 nm pores) that were coated with uniform anatase titania thin films (thickness ≈12 nm, composed of anatase nanocrystals with sizes of ≈4.5 nm). This titania‐coated, nanofibrous, carbon material possesses a specific surface area of 404 m² g^?1, which is two orders of magnitude higher than the titania–cellulose hybrid prepared by atomic layer deposition of titania on the cellulose fibers of filter paper. The photocatalytic activity of the titania–carbon composite was evaluated by the improved photodegradation efficiency of different dyes in aqueous solutions under high‐pressure, fluorescent mercury‐lamp irradiation, as well as the effective photoreduction performance of silver cations to silver nanoparticles with ultraviolet irradiation.     

Sol–Gel Synthesis of Metal–Phenolic Coordination Spheres and Their Derived Carbon Composites

A formaldehyde‐assisted metal–ligand crosslinking strategy is used for the synthesis of metal–phenolic coordination spheres based on sol–gel chemistry. A range of mono‐metal (Co, Fe, Al, Ni, Cu, Zn, Ce), bi‐metal (Fe‐Co, Co‐Zn) and multi‐metal (Fe‐Co‐Ni‐Cu‐Zn) species can be incorporated into the frameworks of the colloidal spheres. The formation of coordination spheres involves the pre‐crosslinking of plant polyphenol (such as tannic acid) by formaldehyde in alkaline ethanol/water solvents, followed by the aggregation assembly of polyphenol oligomers via metal–ligand crosslinking. The coordination spheres can be used as sensors for the analysis of nucleic acid variants with single‐nucleotide discrimination, and a versatile precursor for electrode materials with high electrocatalytic performance.     

Large‐Scale,Bottom‐Up Synthesis of Binary Metal–Organic Framework Nanosheets for Efficient Water Oxidation

Ultrathin metal–organic framework (MOF) nanosheets (NSs) offer potential for many applications, but the synthetic strategies are largely limited to top‐down, low‐yield exfoliation methods. Herein, Ni–M–MOF (M=Fe, Al, Co, Mn, Zn, and Cd) NSs are reported with a thickness of only several atomic layers, prepared by a large‐scale, bottom‐up solvothermal method. The solvent mixture of N,N‐dimethylacetamide and water plays key role in controlling the formation of these two‐dimensional MOF NSs. The MOF NSs can be directly used as efficient electrocatalysts for the oxygen evolution reaction, in which the Ni–Fe–MOF NSs deliver a current density of 10 mA cm^?2 at a low overpotential of 221 mV with a small Tafel slope of 56.0 mV dec^?1, and exhibit excellent stability for at least 20 h without obvious activity decay. Density functional theory calculations on the energy barriers for OER occurring at different metal sites confirm that Fe is the active site for OER at Ni–Fe–MOF NSs.     

Large‐Scale,Bottom‐Up Synthesis of Binary Metal–Organic Framework Nanosheets for Efficient Water Oxidation

Ultrathin metal–organic framework (MOF) nanosheets (NSs) offer potential for many applications, but the synthetic strategies are largely limited to top‐down, low‐yield exfoliation methods. Herein, Ni–M–MOF (M=Fe, Al, Co, Mn, Zn, and Cd) NSs are reported with a thickness of only several atomic layers, prepared by a large‐scale, bottom‐up solvothermal method. The solvent mixture of N,N‐dimethylacetamide and water plays key role in controlling the formation of these two‐dimensional MOF NSs. The MOF NSs can be directly used as efficient electrocatalysts for the oxygen evolution reaction, in which the Ni–Fe–MOF NSs deliver a current density of 10 mA cm^?2 at a low overpotential of 221 mV with a small Tafel slope of 56.0 mV dec^?1, and exhibit excellent stability for at least 20 h without obvious activity decay. Density functional theory calculations on the energy barriers for OER occurring at different metal sites confirm that Fe is the active site for OER at Ni–Fe–MOF NSs.     

Miniaturized pipette‐tip‐based electrospun polyacrylonitrile nanofibers for the micro‐solid‐phase extraction of nitro‐based explosive compounds

In this study, a self‐assembly of miniaturized pipette‐tip‐based solid‐phase extraction for the simultaneous extraction of nitroaromatic compounds was developed, with electrospun polyacrylonitrile nanofibers used as sorbents. The electrospun polyacrylonitrile nanofibers were characterized by scanning electron microscopy, FTIR analysis and surface area analysis. Good linearities for the four nitroaromatic compounds (2,6‐dinitrotoluene, 2‐nitrotoluene, 3‐nitrotoluene, and 4‐nitrotoluene) were obtained in a range of 250–1000 μg/L with coefficients of determination > 0.99. The limits of detection of these analytes were between 21 and 38 μg/L. The results showed that the pipette‐tip‐based solid‐phase extraction was effective in extracting nitrotoluenes in the pH regime of environmental interest (≈ 6). The investigation also revealed that the optimum mass of electrospun polyacrylonitrile nanofibers sorbent was 15 mg and 20 aspirating/dispensing cycles gave the maximum recovery of nitrotoluenes with 200 μL acetonitrile as the best eluting solvent. Moreover, the performance of the present method was studied for the extraction and determination of nitroaromatic compounds in real environmental water samples and good recoveries ranging from 70 to 115% were found, and respective relative standard deviations of <12% were obtained.     

Preparation and Characterization of a Tin Pentacyanonitrosylferrate‐Modified Carbon Ceramic Electrode: Application to Electrocatalytic Oxidation and Amperometric Detection of L‐Cysteine

The sol‐gel technique was used to construct tin pentacyanonitrosylferrate (SnPCNF) modified composite carbon ceramic electrode (CCE). This involves two steps: construction of CCE containing metallic Sn powder and then electrochemical creating of SnPCNF on the surface of CCE. The SnPCNF modified CCE (SnPCNFlCCE) was characterized by energy‐dispersive X‐ray (EDX), FTIR and cyclic voltammetry (CV) techniques. The SnPCNF film showed electrocatalytic activity toward the oxidation of L ‐cysteine. A linear calibration plot was obtained over the L ‐cysteine concentration range 1–51 μM using chronoamperometry. L ‐cysteine was determined amperometrically at the surface of this modified electrode. The detection limit (for a signal to noise of 3) and sensitivity were found to be 0.62 μM and 126 μA/mM, respectively.     

Hierarchical‐Structured Anatase‐Titania/Cellulose Composite Sheet with High Photocatalytic Performance and Antibacterial Activity

Bulk hierarchical anatase‐titania/cellulose composite sheets were fabricated by subjecting an ultrathin titania gel film pre‐deposited filter paper to a solvo‐co‐hydrothermal treatment by using titanium butoxide as the precursor to grow anatase‐titania nanocrystallites on the cellulose nanofiber surfaces. The titanium butoxide specie is firstly absorbed onto the nanofibers of the cellulose substance through a solvothermal process, which was thereafter hydrolyzed and crystallized upon the subsequent hydrothermal treatment, leading to the formation of fine anatase‐titania nanoparticles with sizes of 2–5 nm uniformly anchored on the cellulose nanofibers. The resulting anatase‐titania/cellulose composite sheet shows a significant photocatalytic performance towards degradation of a methylene blue dye, and introduction of silver nanoparticles into the composite sheet yields an Ag‐NP/anatase‐titania/cellulose composite material possessing excellent antibacterial activity against both Gram‐positive and Gram‐negative bacteria.     

Band‐Gap Control of Zinc Sulfide: Towards an Efficient Visible‐Light‐Sensitive Photocatalyst

The electronic properties of transition‐metal‐doped zinc sulfide (ZnS) have been investigated by using first‐principles calculations. Transition‐metal doping can allow electronic transitions at energies corresponding to visible‐light wavelengths, thus potentially resulting in increased photocatalytic efficiency under sunlight. In particular, our calculations show that transition‐metal atoms that produce little lattice strain, such as Co, Ni, Mn, and Fe, can be readily incorporated in ZnS. Due to their low formation energies and appropriate band energies, we predict that Ni‐ and Co‐doped ZnS will be promising materials for photocatalytic hydrogen production.     

Physicochemical characterization of nanobidentate ferrocene‐based Schiff base ligand and its coordination complexes: Antimicrobial,anticancer, density functional theory,and molecular operating environment studies

A novel bidentate Schiff base ligand (HL, Nanobidentate Ferrocene based Schiff base ligand L (has one replaceable proton H)) was prepared via the condensation of 2‐amino phenol with 2‐acetyl ferrocene. The ligand was characterized using elemental analysis, mass spectrometry, infrared (IR) spectroscopy, ¹proton nuclear magnetic resonance (H‐NMR) spectroscopy, scanning electron microscopy (SEM), and thermal analysis. The corresponding 1:1 metal complexes with some transition‐metal ions were additionally characterized by their elemental analysis, molar conductance, SEM, and thermogravimetric ana1ysis (TGA). The complexes had the general formula [M(L)(Cl)(H₂O)₃]xCl·nH₂O (M = Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II)), (x = 0 for Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II), x = 1 for Cr(III) and Fe(III)), (n = 1 for Cr(III), n = 3 for Mn(II) and Co(II), n = 4 for Fe(III), Ni(II), Cu(II), Zn(II), and Cd(II)). Density functional theory calculations on the HL ligand were also carried out in order to clarify molecular structures by the B31YP exchange‐correlation function. The results were subjected to molecular orbital diagram, highest occupied mo1ecu1ar orbital–lowest occupied molecular orbital, and molecular electrostatic potential calculations. The parent Schiff base and its eight metal complexes were assayed against four bacterial species (two Gram‐negative and two‐Gram positive) and four different antifungal species. The HL ligand was docked using molecular operating environment 2008 with crystal structures of oxidoreductase (1CX2), protein phosphatase of the fungus Candida albicans (5JPE), Gram(?) bacteria Escherichia coli (3T88), Gram(+) bacteria Staphylococcus aureus (3Q8U), and an androgen‐independent receptor of prostate cancer (1GS4). In order to assess cytotoxic nature of the prepared HL ligand and its complexes, the compounds were screened against the Michigan cancer foundation (MCF)‐7 breast cancer cell line, and the IC₅₀ values of compounds were calculated.     

Selective retention of basic compounds by metal aquo‐ion affinity chromatography

A novel metal aquo‐ion affinity chromatography has been developed for the analysis of basic compounds using heat‐treated silica gel containing hydrated metal cations (metal aquo‐ions) as the packing material. The packing materials of the metal aquo‐ion affinity chromatography were prepared by the immobilization of a single metal component such as Fe(III), Al(III), Ag(I), and Ni(II) on silica gel followed by extensive heat treatment. The immobilized metals form aquo‐ions to present cation‐exchange ability for basic analytes and the cation‐exchange ability for basic analytes depends on pK_a of the immobilized metal species. In the present study, to evaluate the retention characteristics of metal aquo‐ion affinity chromatography, the on‐line solid‐phase extraction of drugs was investigated. Obtained data clearly evidence the selective retention capability of metal aquo‐ion affinity chromatography for basic analytes with sufficient capacity.     

Trialkoxysilane‐capped acrylic resin/titania organic–inorganic hybrid optical films prepared by the sol–gel process

Homogeneous organic–inorganic hybrid materials with excellent thermal and optical performance were successfully prepared via the mixing of (3‐methacryloxypropyl)trimethoxysilane‐capped acrylic resin with titania synthesized by sol–gel approaches. The effects of the titania content, amount of water, and pH in the sol–gel and the ratio of the solvents (butyl acetate and ethanol) on the structures and properties of the hybrid materials were studied. More titania, more water, and base catalysis in the sol–gel process and a higher ratio of butyl acetate to ethanol for the hybrids led to a larger size and a more compact structure of the titania phase. Increasing the titania content dramatically improved the glass‐transition temperature, UV‐shielding properties, and refractive index for the hybrid materials, and it did not reduce their optical transparency. In general, better thermal stability and optical properties were achieved for the hybrid materials prepared with less water, lower pH values (e.g., acidic or neutral conditions), and a lower ratio of butyl acetate to ethanol. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 637–649, 2005     

Metal‐Organic Niccolite: Synthesis,Structures, Phase Transition,and Magnetic Properties of [CH3NH2(CH2)2NH2CH3][M2(HCOO)6] (M=divalent Mn,Fe, Co,Ni, Cu and Zn)

We report the synthesis, crystal structures, thermal and magnetic characterizations of a family of metal‐organic frameworks adopting the niccolite (NiAs) structure, [dmenH₂²⁺][M₂(HCOO)₆²⁻] (dmen=N,N′‐dimethylethylenediamine; M=divalent Mn, 1Mn ; Fe, 2Fe ; Co, 3Co ; Ni, 4Ni ; Cu, 5Cu ; and Zn, 6Zn ). The compounds could be synthesized by either a diffusion method or directly mixing reactants in methanol or methanol–water mixed solvents. The five members, 1Mn , 2Fe , 3Co , 4Ni , and 6Zn are isostructural and crystallize in the trigonal space group P 1c, while 5Cu crystallizes in C2/c. In the structures, the octahedrally coordinated metal ions are connected by anti–anti formate bridges, thus forming the anionic NiAs‐type frameworks of [M₂(HCOO)₆²⁻], with dmenH₂²⁺ located in the cavities of the frameworks. Owing to the Jahn–Teller effect of the Cu²⁺ ion, the 3D framework of 5Cu consists of zigzag Cu‐formate chains with Cu OCHO Cu connections through short basal Cu O bonds, further linked by the long axial Cu O bonds. 6Zn exhibits a phase transition probably as a result of the order–disorder transition of the dmenH₂²⁺ cation around 300 K, confirmed by differential scanning calorimetry and single crystal X‐ray diffraction patterns under different temperatures. Magnetic investigation reveals that the four magnetic members, 1Mn , 2Fe , 3Co , and 4Ni , display spin‐canted antiferromagnetism, with a Néel temperature of 8.6 K, 19.8 K, 16.4 K, and 33.7 K, respectively. The Mn, Fe, and Ni members show spin‐flop transitions below 50 kOe. 2Fe possesses a large hysteresis loop with a large coercive field of 10.8 kOe. The Cu member, 5Cu , shows overall antiferromagnetism (both inter‐ and intra‐chains) with low‐dimensional characteristics.     

Theoretical studies of new Schiff base ligand derived from 1,3‐diaminopropane and 2‐acetyl ferrocene and studying some applications of its metal complexes

A novel bidentate Schiff base ligand (L) and some d‐transition metal chelates (Cr (III), Mn (II), Fe (III), Co (II), Ni (II), Cu (II), Zn (II) and Cd (II)) were synthesized and characterized using various physicochemical and spectroscopic techniques like elemental analysis, IR, mass, UV–visible and thermal analysis. The spectroscopic data suggested that the parent Schiff base ligand coordinated to the metal ions through both imine nitrogen atoms. The molecular and electronic structure of the free ligand was optimized theoretically, and the quantum chemical parameters were calculated. The molecular structure can be used to investigate the coordination sites and the total charge density around each atom. The free ligand and its complexes were screened for their antimicrobial activities for various pathogenic bacteria and fungi. The anticancer activities of the free ligand, Cr (III), Mn (II) and Fe (III) complexes were screened against MCF‐7 cell line and found that Mn (II) complex has the lowest IC₅₀ (15.90 μg/ml). Molecular docking was used to predict the binding between the free ligand with receptor of mutant human androgen (ARccr) derived from androgen‐independent prostate cancer (1GS4), crystal structure of yeast‐specific serine/threonine protein phosphatase (ppz1) of Candida Albicans (5JPE) and crystal structure of renal tumor suppressor protein, folliculin (3 V42) and to identify the binding mode and the crucial functional groups interacting with the three proteins.     

Silica/poly (N‐vinylimidazolium) nanospheres by combined RAFT polymerization and thiol‐ene click chemistry

We report a facile method that combined sol–gel reaction, reversible addition–fragmentation chain transfer (RAFT)/macromolecular design via interchange of the xanthates process and thiol‐ene click reaction to prepare monodisperse silica core‐poly(N‐vinylimidazole) (PVim) shell microspheres of 200 nm in average diameters. First, silica with C = C double bonds was prepared by the sol–gel reaction of 3‐(trimethoxysilyl)propyl methacrylates (MPS) with tetraethoxysilane in ethanol; SiO₂@PVim were subsequently prepared by grafting PVim chain (Mn = 9800 g/mol, polydispersity index = 1.22) to MPS‐SiO₂ via the thiol‐ene click chemisty. The obtained SiO₂@PVim microspheres show higher catalytic activity toward the hydrolysis of p‐nitrophenyl acetate compared with the PVim homopolymers. The as‐prepared composites have been characterized by scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis and Fourier transform infrared spectrometry analysis. Copyright © 2014 John Wiley & Sons, Ltd.     

Role of Transition Metals in UV‐B‐Induced Damage to Bacteria

The purpose of this study was to explore the possible link between metals and UV‐B‐induced damage in bacteria. The effect of growth in the presence of enhanced concentrations of different transition metals (Co, Cu, Fe, Mn and Zn) on the UV‐B sensitivity of a set of bacterial isolates was explored in terms of survival, activity and oxidative stress biomarkers (ROS generation, damage to DNA, lipid and proteins and activity of antioxidant enzymes). Metal amendment, particularly Fe, Cu and Mn, enhanced bacterial inactivation during irradiation by up to 35.8%. Amendment with Fe increased ROS generation during irradiation by 1.2–13.3%, DNA damage by 10.8–37.4% and lipid oxidative damage by 9.6–68.7%. Lipid damage during irradiation also increased after incubation with Cu and Co by up to 66.8% and 56.5% respectively. Mn amendment decreased protein carbonylation during irradiation by up to 44.2%. These results suggest a role of Fe, Co, Cu and Mn in UV‐B‐induced bacterial inactivation and the importance of metal homeostasis to limit the detrimental effects of ROS generated during irradiation.