Ruizpayne7353

Chitosan-modified magnetic Schiff base network composite nanospheres (Fe3O4@SNW@Chitosan) were prepared for the enrichment and detection of hippuric acid (HA) and 4-methyl hippuric acid (4-MHA) via magnetic solid phase extraction (MSPE) connected with HPLC. The SNW was one of the covalent organic framework, which constructed through covalent bonds, shown comprising solvent stability, low density and accessible pores. The obtained Fe3O4@SNW@Chitosan has many merits as a magnetic sorbent, including a hydrophilic surface, uniform pore size, unique ordered channel structure, and superparamagnetism. The favourable linearity of this MSPE-HPLC method was in the range of 1-1000 μg L-1, and LODs of HA and 4-MHA were 0.3 μg L-1 and 0.2 μg L-1, respectively. The recoveries in urine samples were range from 95.3 to 109.0 % with the RSD less than 9.6 %. When employed for the enrichment of HA and 4-MHA, Fe3O4@SNW@Chitosan exhibited great potential as a candidate for preconcentration.A portable and automated IC system with a dual-capability for the analysis of both fresh and saline environmental waters has been developed. Detection of nitrate in complex matrices such as seawater was achieved by the employment of an automated two-dimensional (heart-cut) IC method utilised in tandem with on-column matrix elimination, using a sodium chloride eluent. The system also demonstrated the capability to switch to a second mode of analysis, whereby direct one-dimensional IC analysis was employed to rapidly detect nitrite and nitrate in freshwater, with direct UV LED based absorption detection in under 3 minutes. Calibration curves using a 195 µL sample loop were generated for both freshwater and artificial seawater samples. For marine analysis, an analytical range of 0.1 mg L-1 - 40 mg L-1 NO3- was possible, while an analytical range (0.1 mg L-1 - 15 mg L-1 NO2-, 0.2 - 30 mg L-1 NO3-) appropriate for freshwater analysis was also achieved. Chromatographic repeatability for both marine and freshwater analysis was verified over 40 sequential runs with RSD values of less then 1% demonstrated for both peak area and retention times for each mode of analysis. The selectivity of both methods was demonstrated with interference tests with common anions present in environmental waters. Recovery analysis was carried out on marine samples from Tramore Bay, Co. Waterford, Ireland, and the systems analytical performance was compared with that of an accredited IC following environmental sample analysis.A fast and automated separation and quantification method for bromide and the artificial nucleoside 5-bromo-2'-deoxyuridine (5-BrdU) via hyphenation of ion exchange chromatography (IC) and inductively coupled plasma-mass spectrometry (ICP-MS) is presented. The analysis of these two species is relevant to monitor the transfer of electrons along metal-mediated DNA base pairs. Charge transfer in DNA is of high interest for the implementation in nanotechnological applications like molecular wires. 5-BrdU as part of the DNA sequence releases bromide upon one electron reduction after efficient electron transfer along the DNA. The concentrations of 5-BrdU and bromide in enzymatically digested DNA samples can therefore be used as a marker for the efficiency of electron transfer along the DNA helix. A large number of samples was analyzed using an automated IC system. This platform enables time-efficient external calibration by inline dilution of a stock solution. Due to the fast separation of the two bromine species in less than 90 s, the developed method is suitable for screening applications with a multitude of samples. Despite the isobaric interferences and a low degree of ionization for bromine detection via ICP-MS the method has a limit of detection (LOD) of 30 ng/L which is approximately an order of magnitude lower than a comparable method using reversed phase high performance liquid chromatography (RP-HPLC) and ICP-MS.An ordered 3D printed chromatography stationary phase was used to purify M13 bacteriophage (M13) directly from crude cell culture. This new approach, which offers the same advantages as expanded bed adsorption (EBA) with regard to tolerating solids-laden feed streams but without the corresponding issues associated with fluidized bed stability that affect the latter, can be described as "printed monolith adsorption (PMA)". PMA columns (5, 10 and 15 cm length by 1 cm diameter) were made via a wax templating method from cross-linked cellulose hydrogel and functionalized with a quaternary amine ligand. The recovery of M13 was found to be strongly linked to load flow rate, with the highest recovery 89.7% ± 6% for 1.4 × 1011 pfu/mL of resin occurring at 76 cm/h with a 10 cm column length. A recovery of 87.7% ± 5% for 1.49 × 1011 pfu/mL of media was achieved with a 15 cm column length under conditions comparable to a reported EBA process. The PMA process was completed three times faster than EBA because PMA flow rates can readily be adjusted during operation, with high flow rates and low back pressure, which is unique to the ordered monolithic media geometry used. Equilibration, wash, and cleaning steps were carried out at high flow rates (611 cm/h), minimizing process time and were limited only by the volumetric flow rate capacity of the pumps used, rather than column back pressure ( less then 0.1 MPa at 611 cm/hr). Initial capture of M13 appears to occur on the surface of the monolith solid phase (i.e. the mobile phase channel walls) and subsequently, at a slower rate, within the internal pores of the solid phase media. Y-27632 supplier The difference in binding rate between these two sites is likely caused by slow pore diffusion of the large M13 particles into the pores, with similar slow diffusion out of the pores resulting in tailing of the elution peak. The results indicate that PMA is a promising technology for the efficient purification of viruses directly from crude cell culture.Multi-residue analysis is highly desirable for water quality control. To this end, a comprehensive workflow for the quantitative analysis of 172 anthropogenic organic compounds belonging to emerging contaminants (pharmaceuticals and personal care products, illicit drugs, organophosphate flame retardants and perfluoroalkyl substances) has been developed for application to wastewater and tap water, based on solid phase extraction (SPE) and Orbitrap high resolution mass spectrometry (HRMS). Due to the large number of analytes with various physicochemical characteristics that should be efficiently extracted, the response surface methodology (RSM) employing a central composite design (CCD) and desirability function (DF) approach was exploited to optimize the sample preparation process, instead of the conventional single-factor analysis. The factors included in the design of experiments (DoE) were sample pH, eluent solvents composition and volume. Statistical analysis (ANOVA) proved the adequacy of the proposed model (2- factor interaction) as p-value less then 0.