Application Notes: Sample Prep
Drug Analysis from Oral Fluids
April 7th 2016Using oral fluid as the matrix, a viable and simple solid phase extraction method for a wide range of drugs is developed. Several oral fluid collection devices were evaluated to determine the effectiveness of the cleanup procedure, ultimately confirming that the method is both robust and widely applicable.
Drug Screening from Whole Blood
April 7th 2016A suite of unknown drug compounds from whole blood are analyzed by LC–MS-MS, requiring the need for an effective yet nonspecific cleanup technique. The resulting method demonstrates a simple and fast sample preparation procedure that is suitable for screening many compounds.
Drug Screening from Whole Blood
April 7th 2016A suite of unknown drug compounds from whole blood are analyzed by LC–MS-MS, requiring the need for an effective yet nonspecific cleanup technique. The resulting method demonstrates a simple and fast sample preparation procedure that is suitable for screening many compounds.
On-line SPE-LC of Catecholamines in Urine with Fluorescence Detection
December 2nd 2009Catecholamines are important markers for the diagnosis and management of tumour diseases of the sympathoadrenal system. The major catecholamines are dopamine, norepinephrine and epinephrine. Urine tests have shown to be applicable to measure the level of catecholamines in the human body. Various separation methods have been used for the clean-up of catecholamines in biological fluids: solvent extraction, adsorption on alumina, ion-exchange and solid-phase extraction of a diphenylboronic acid-catecholamine complex. From the point of simplicity, reproducibility and automation the last method is the most suitable and can be realized by on-line SPE–LC. Diphenylborate forms a negatively charged complex with the diol groups of catecholamines. These complexes which are strongly retained on a polystyrene-divinylbenzene cartridge in alkaline medium (pH 8.5) can be eluted in a second step from the SPE unit directly onto the HPLC column. The separation of catecholamines is performed in isocratic mode by..
High Throughput Extraction of Melamine using EVOLUTE CX Mixed-mode SPE Plates
July 2nd 2009The use of EVOLUTE CX mixed-mode columns provides high and consistent recoveries across a range of complex matrices, from biological fluids to milk products. The dual retention mechanism ensures that matrix components such as proteins, salts and phospholipids are removed, resulting in lower ion suppression and accurate analysis.
Total Rapid Prep for Same Day Turnaround of POPs Analysis
June 1st 2009Human health not only depends on providing good medical care, but also on the priority given to prevent exposure to environmental and other health risks. Persistent Organic Pollutants (POPs) are organic compounds typically of anthropogenic origin that resist degradation and accumulate in the food chain and are associated with adverse effects on human health and the environment (1). Due to their toxicity to humans, at much lower concentration than other pollutants, it is important to monitor compounds like polychlorinated dioxins/furans PCDD/Fs, DLPCBs, BDEs, and PCNs. More sophisticated requirements are needed for their analysis. In the past, extraction and clean-up of POPs present in fish and biota samples were conducted with procedures such as Soxhlet extraction, acid digestion, and liquid-liquid extraction. The clean-up of these samples was accomplished through chromatographic columns using different types of adsorption media such as silica, alumina, and carbon. These analytical methods used for analysis..
Two Novel Polysaccharide-Based Chiral Stationary Phases: CHIRALPAKˆ® AY-H and CHIRALCELˆ® OZ-H
June 1st 2009Polysaccharide-based chiral stationary phases (CSP) are successfully employed to achieve the majority of analytical and preparative enantioselective separations. However, there are a number of separations where significant modification or enhancement of selectivity is necessary. Two new columns, CHIRALPAK AY-H and CHIRALCEL OZ-H, have been introduced to meet these needs.
The Integration of Microextraction Packed Sorbent (MEPS) into Multidimensional Strategies
March 2nd 2009LC/GC approaches to analysis are attractive because they combine the selectivity of solid-phase sorbents in the first dimension with the separating power and peak capacity of capillary GC in the following dimensions.
The Integration of Microextraction Packed Sorbent (MEPS) into Multidimensional Stratagies
February 1st 2009LC–GC approaches to analysis are particularly attractive because they combine the selectivity of solid phase sorbents in the first dimension with the separating power and peak capacity of a capillary GC column in the following dimensions. Their widespread use is limited because of the difficultly in desolvating the stream from the LC dimension without the solvent vapour passing down the GC column in significant quantity. An alternative approach to elution chromatography in the first dimension is to harness the specificity of the solid-phase process for digital chromatography using discontinuous changes in solvent polarity. Digital chromatography on a small sorbent bed reduces the volume of mobile phase to discrete plugs that are sufficiently small to be injected directly into a GC with a large volume injector or, alternatively, subsampled into a conventional split/splitless injector.
Reversed-Phase Enantioselective Chromatography with New µ-mm Chiral Stationary Phases
February 1st 2009To meet the growing need for fast reversed-phase enantiomer separations, two new 3-μm reversed-phase columns, CHIRALCEL® OD® -3R and CHIRALPAK® AD® -3R, have been introduced. High column performance and column stability under a wide range of conditions, including aqueous solvent systems suited to LC–MS, have been
Memory Effects of Mobile Phase Additives on the Whelk-O®1 Chiral Phase
February 1st 2009The Pirkle - Type Whelk-O®1 CSP is a synthetically made chiral selector covalently bonded to a silica support. This phase is well known in the industry for its broad degree of generality, mobile phase compatibility, and ability to invert elution order. Most commonly used polysaccharide coated CSP's are sensitive to the presence of certain mobile phase modifiers such as DEA, TEA, and TFA. Retained memory effects can adversely affect a separation resulting in broad and tailing peaks, no peak elution, and reduced or loss of separation altogether. To remove these unwanted memory effects, the column must be rinsed with an alcohol, such as methanol or ethanol. This is a time consuming and costly process. The Whelk-O®1 CSP does not exhibit any such retained memory behavior.
A Highly Sensitive Method for the Analysis of Tamsulosin (Flomax) in Human Plasma
December 2nd 2008A highly sensitive analytical method for the analysis of tamsulosin in human plasma has been developed for use in bioanalytical studies. The solid-phase extraction (SPE) and UPLC–MS–MS methodologies are described, as well as performance against validation parameters.
Multi-Residue Analysis of Pesticides in Fruits Using DisQuE, a Dispersive Solid-Phase Extraction Kit
September 1st 2008A new technique, QuEChERS, standing for Quick, Easy, Cheap, Effective, Rugged, and Safe, is readily accepted by both the AOAC International and the Committee of European Normalization (CEN) for the pesticide residues in foods and agriculture products. Waters DisQuEâ„¢ Dispersive Sample Preparation Kit contains conveniently-packaged centrifuge tubes with pre-weighed sorbents and buffers designed for use with the AOAC official QuEChERS methods.
Techniques for Reducing Purge-and-Trap Cycle Times in VOC Analysis
September 1st 2008The purge-and-trap (P&T) technique for analysis of volatile organic compounds (VOCs) was pioneered in the 1970s at the United States Environmental Protection Agency (USEPA) research laboratory in Cincinnati. Many of the operational parameters developed during this time period are still included in USEPA methods. While these parameters still produce good analytical results, they do not take advantage of advances in instrumentation that enable analysis of emerging contaminants such as fuel oxygenates, and increased sample throughput.
Investigation of Branched Polydienes with GPC/MALS
September 1st 2008Our work focuses on the synthesis of branched (functionalized) polydienes via a facile two-step synthesis. Despite the numerous strategies developed for the preparation of branched polymers in recent years, there is still a limited number of simple synthetic strategies based on common vinyl monomers.
On-Site Sample Preparation Using MEPS for Waste Water Analysis
September 1st 2008MEPS uses a barrel insert and needle (BIN) device to reduce Solid-Phase Extraction (SPE) to a micro-scale suitable for small volume samples and for the online adaptation of conventional SPE techniques. Because the SPE cartridge (BIN) is incorporated into the needle assembly of a gas-tight syringe, MEPS is also a simple field-portable SPE device that may be operated manually without need for sampling pumps or, alternatively, may be incorporated into robotic samplers. MEPS devices are of glass and stainless steel construction allowing them to be fully immersed for sampling at depth or, alternatively, used at needle depth to avoid perturbing the stream from which the sample was drawn. An extension pole allowed MEPS to be used to sample back along pipes or down inspection vents. When sampling from drainage pits and open sumps, there was minimal requirement to remove grates to gain access. An extension pole also allowed sampling from outflows that were offensive and could be readily adapted for safe sampling of..
A Highly Selective Method for the Analysis of Drospirenone in Human Plasma
July 2nd 2008Several common birth control formulations contain both drospirenone and ethinyl estradiol. A highly selective and sensitive analytical method for the analysis of drospirenone in human plasma has been developed for use in bioequivalence studies. The solid-phase extraction (SPE) and UPLC–MS–MS methodologies are described as well as performance against validation parameters.