Search results for "Sample preparation"
showing 10 items of 343 documents
Determination of metabolite concentrations in human brain tumour biopsy samples using HR-MAS and ERETIC measurements.
2009
Accurate determination of the concentration of the metabolites contained in intact human biopsies of 10 glioblastoma multiforme samples was achieved using one-dimensional 1H high-resolution magic angle spinning (HR-MAS) NMR combined with ERETIC™ (electronic reference to in vivo concentrations) measurements. The amount of sample used ranged from 6.8 to 12.9 mg. Metabolite concentrations were measured in each sample using two methods: with DSS (2,2-dimethyl-2-silapentane-5-sulfonate sodium salt) as an internal reference and with ERETIC™ as an external electronically generated reference. The ERETIC™ signal was shown to be highly reproducible and did not affect the spectral quality. The concent…
Quantitative Proteome and Phosphoproteome Profiling in Magnaporthe oryzae
2021
The quality and consistency in every sample preparation procedure is crucial for any scientific output. Therefore, it is of utmost importance to have easy, economic, and robust sample preparation protocols. Here, we describe a simple and robust bottom-up proteomic sample preparation strategy for identification and label-free quantification (LFQ) of proteins and phosphoproteins. The presented workflow is designed for large-scale application and involves easy scalable and well-known robust sample preparation techniques, such as cell lysis with SDS buffer under heat, protein precipitation using methanol/chloroform, tryptic digest, and commercially available TiO2 phosphopeptide enrichment kits.…
Sorption of copper(II) ions in the biomass of alga Spirogyra sp.
2012
Abstract Sorption of copper ions by the alga Spirogyra sp. was investigated to determine the influence of experimental conditions and the methods of sample preparation on the process. The experiments were carried out both under the static and the dynamic conditions. Kinetics and equilibrium parameters of the sorption were evaluated. In addition, the influence was studied of the algae preparation methods on the conductivity of demineralized water in which the algae samples were immersed. The static experiments showed that the sorption of Cu2+ ions reached equilibrium in about 30 min, with approximately 90% of the ions adsorbed in the initial 15 min. The sorption capacity determined from the …
The application of molecular imprinting technology to solid phase extraction
2001
In parallel to a long lasting search for universal multi-purpose sorbents, the area of solid phase extraction (SPE) is recently experiencing a rapid development of new types of tailor-made class specific or compound-specific sorbents which are designed to respond to the increasing demand for selectivity and efficiency in sample clean-up prior to quantification. An important issue here is the enrichment and clean-up of complex samples, such as environmental waters, sediments, biofluids and foodstuffs prior to detection. This because the analyte is often present in low concentration in a complex mixture of similar compounds and therefore needs to be isolated and enriched in order to be detect…
F-2-isoprostanes: review of analytical methods
2006
International audience; F2-isoprostanes (F2-isoPs) represent a new family of biomarkers for oxidative stress generated by free radical attack of membrane-bounded arachidonic acid. Esterified F2-isoPs can be found in tissue or plasma lipids whereas the free form F2-isoPs, hydrolyzed by phospholipase, is mainly present in body fluids. The extent of systematic damage due to oxidative stress within the body can be assessed by the determination of plasma or urine F2-isoPs. The determination of F2-isoPs in clinical practice is not often used due to the complexity to extract the compounds from their biologic matrixes before the analysis step. In most of published protocols, extraction procedure is…
Determination of organic and inorganic mercury species in water and sediment samples by HPLC on-line coupled with ICP-MS.
2009
This paper describes a preconcentration method for Hg(2+) and MeHg(+) in water samples using sodium diethyldithiocarbamate immobilized in polyurethane foam (PU-NaDDC) and an extraction method for several mercury species in sediment samples, including MeHg(+), EtHg(+) and PhHg(+), which is simple, rapid, and uses a single organic solvent. Separation and measurement were done by high-performance liquid chromatography on-line with inductively coupled plasma mass spectrometry (HPLC/ICP-MS). Initially, the test of recovery was applied using procedures compatible with HPLC. Under the optimum extraction conditions, recoveries of 96.7, 96.3 and 97.3% were obtained for MeHg(+), EtHg(+), and PhHg(+),…
Development and validation of a radioimmunoassay for serum melatonin.
1989
A radioimmunoassay using N-[3-(4-hydroxy-3-[4-hydroxy-3- [125I]iodophenylpropionyl)]-5-methoxytryptamine as tracer for determination of melatonin in the serum of different species is described. Melatonin antisera were raised in rabbits by immunization with a bovine serum albumin conjugate of N-[3-(2-aminoethyl)-5-methoxy indole] hemisuccinamide. A single high affinity, specific antiserum was obtained. In contrast to previous studies, the tracer was synthesised in one step in the absence of water, giving an excellent yield of highly pure product. No chromatographic purification step was needed. Polyethylene glycol in combination with goat antirabbit immunoglobulins was used to separate bound…
Investigation of cuticular hydrocarbons from Bagrada hilaris genders by SPME/GC-MS
2007
The cuticular hydrocarbons of male and female Bagrada hilaris Burmeister (Heteroptera: Pentatomidae) were investigated, by headspace solid-phase microextraction followed by gas chromatography-mass spectrometry. Measurements were done with fiber coatings of different polarity after optimization of headspace volumes and extraction temperatures. This resulted in the use of polyacrylate fiber, 22-ml vial as the sample holder, and an extraction temperature of 150 degrees C. The analytical procedures allowed identification of 13 peaks, corresponding to a homologous series of n-alkanes (nC(17)-nC(29)). The hydrocarbon profiles of male and female B. hilaris were qualitatively equal, but marked sex-…
Determination of microcystins in fish by solvent extraction and liquid chromatography
2005
A liquid chromatography electrospray mass spectrometry (LC/ESI/MS) method has been developed to identify and quantify microcystins in fish liver and intestine. Microcystins (MCs) were extracted from 500 mg sample with methanol-water (85:25, v/v) and the extracts concentrated to 250 microl. The parameters were optimized by a full factorial 2(3) design. Neither laborious pre-treatment nor clean up were necessary. MCs were separated using conventional C18 column and an acetonitrile-acidified water (pH 3) gradient. Negative samples (without MCs) were discriminated by liquid chromatography diode array detection (LC/DAD). The limits of detection (LOD) and the limits of quantification (LOQ) result…
Validation of a method for the determination of boron in ceramic materials by X-ray fluorescence spectrometry
2000
Abstract A method is proposed for boron determination in ceramic materials, boracic raw materials and ceramics frits of different compositions by wavelength dispersive X-ray fluorescence technique. The instrumental conditions were studied and the sample preparation procedures were optimized. The reference method used was the potentiometric titration of mannitol–boric complex acid and the technique was optimized for the determination of B 2 O 3 in each of the materials used. The samples for XRF determination were obtained as pellets and as glass discs. For the pellets different binders were studied, such as mannitol and cellullose for the samples of raw materials, and polyvinylpirrolidone an…