349 Results for: "Mobile phases and phase modifiers"

Supplier: Merck

The LC-ABZ phase has a unique deactivation technology which provides excellent reversed-phase performance for basic compounds, as well as those that are acidic, polar neutral, and non-polar.

Supplier: Merck

These SUPELCOSIL LC-DB phases are specially deactivated for basic compounds. These columns provide less retention, better peak shape, and higher efficiency for organic bases than can be obtained on conventional reversed-phase columns.

Supplier: Merck

HPTLC LiChrospher® plates are based on spherical-shaped silica 60 with a particle size of 7 µm, and narrow particle size distribution similar to the phases used in HPLC. LiChrospher® HPTLC plates possess a selectivity that is comparable to respective HPTLC plates, however, plate height and separation numbers are further improved resulting in shorter analysis times.

Supplier: Merck

Tetrabutylammonium hydroxide (TBAOH) is a quaternary ammonium salt,mainly used as a strong base and phase-transfer catalyst.

Supplier: Merck

Clear, colorless fluid polymer useful as a stationary phase in gas chromatography and as an anti-foaming agent.

Supplier: Merck

4-Hydroxy-4-methyl-2-pentanone may be used as an internal standard in the analysis of volatile odor-active compounds present in wine using solid phase extraction with gas chromatography (SPE-GC).

Supplier: Merck

Bisphenol E may be used as a reference standard in the determination of bisphenol E in beverages using on-line solid-phase extraction with fast liquid chromatography coupled with tandem mass spectrometry (on-line SPE fast LC-MS/MS).

Supplier: Merck

Chromolith® Prep monolithic stationary phases are new ultrapure silica phases which gain their special properties from a bimodal pore structure. This structure is a property of the new 'Sol-Gel' technology and consists of macropores and mesopores. The mesopores with an average diameter of 12 nm, form the fine porous structure of the column interior and create a very large surface area on which adsorption of the target compounds occurs.

Supplier: Merck

Monolinuron CRM may also be used as given below: Determination of 252 pesticides extracted from surface water samples by solid-phase extraction (SPE) using liquid chromatography quadrupole-orbitrap high-resolution tandem mass spectrometry. Extraction of 13 pesticides from four groundwater and three river water samples using silica-based MSU-1 mesoporous solid as a sorbent for their solid-phase extraction (SPE) followed by ultra-performance liquid chromatography-triple quadrupole-mass spectrometric (UHPLC- QqQ-MS/MS) determination. Development and validation of a UHPLC-diode array detection (DAD) method for simultaneous determination of urea and tebuthiuron herbicides in four fresh vegetable samples. Multi-residue analysis of 50 herbicides in 51 grain samples of soybean corn and wheat by ultra-performance liquid chromatography-electrospray ionisation-mass spectrometry (UPLC-ESI-MS). Extraction of 109 pesticide residues from different chemical classes from 345 tomato samples by modified QuEChERS method and their determination using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Simultaneous analysis of 238 pesticides and 78 veterinary drugs in 80 bovine milk samples using ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS).

Supplier: Merck

Simazine CRM may also be used as given below: Development and validation of an ultrasonic-assisted dispersive liquid-liquid microextraction (UA-DLLME) method for sample extraction followed by gas chromatography-mass spectrometry based determination of endocrine-disrupting herbicides in the river and seawater samples. Determination of triazine pesticide residues in samples of apples pears carrots potatoes tomatoes avocado cucumber spinach bananas and oranges by modified QuEChERS and solid-phase extraction (SPE) procedures followed by liquid chromatography-photodiode array (LC-DAD) analysis. Multi-residue analysis of 67 pesticides in olive oil olives and avocado samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to evaluate various clean-up sorbents. Quantitation of 20 pesticides in eel and shrimp samples by a scheduled multiple reaction monitoring (sMRM) method and QuEChERS with EDTA for sample extraction and purification. Analysis of 35 micropollutants including pesticides in water samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after their solid-phase extraction. Simultaneous quantification of 58 pharmaceuticals and personal care products (PPCPs) and pesticides in water samples by solvent-based de-emulsification dispersive liquid-liquid microextraction (SD-DLLME) combined with liquid chromatography-tandem mass spectrometry (LCMS/MS).

Supplier: Merck

Ascentis® Silica HPLC columns for the classic use in normal phase HPLC.

Supplier: Merck

Purospher® STAR HPLC columns based on highest purity silica are also available for normal phase separations.

Supplier: Merck

All the individual steps associated with solid phase extraction can be carried out using the LiChrolut® extraction unit. This transparent and vacuum-suitable unit, made of glass, can be used to prepare up to 12 samples simultaneously.

Supplier: Merck

BIOshell™ 160 Å Peptide CN columns provide an alternative selectivity to the traditional C18 bonded phases.

Supplier: Merck

These phases are used to deactivate the basic compounds. Widely used in industries to analyse the difficult in basic compounds.

Supplier: Merck

Ammonium dihydrogen phosphate 100 g/l in water modifier phosphate modifier for graphite furnace AAS, Supelco®

Supplier: Merck

Solid phase extraction vacuum manifolds allow to simultaneously process up to 12 or up to 24 SPE tubes. Precise flow control is provided through each SPE tube by rotating the independent, screw-type valves in the cover, this ensures the packing will not dry out in some tubes while others finish draining.

Supplier: Merck

Magnesium matrix modifier for graphite furnace AAS.

Supplier: Merck

Triclosan-methyl has been used as antimicrobial agent in assay as positive controls in the isolation and identification of active antimicrobial compounds from E. linza algae extract, which was analysed using reversed phase high performance liquid chromatography method (RP-HPLC) and gas chromatography method (GC) coupled with mass spectroscopy, and further confirmed by nuclear magnetic resonance studies (NMR).

Supplier: Merck

Unmodified and modified cellulose plates for the analysis of polar substances.

Supplier: Merck

Ascentis^® Express ES-C18 is a non-endcapped C18 stationary phase based on the proven Fused-Core^® particle design.

Supplier: Merck

Ascentis® Express PAH is a non endcapped C18 bonded phase with a proprietary manufacturing process designed on proven Fused-Core® technology to provide a fast and efficient separation of PAH compounds.

Supplier: Merck

Metrafenone CRM may also be used in the residue analysis of: 209 pesticides and persistent organic pollutants (POPs) extracted by QuEChERS-based procedure from fresh bovine and chicken liver samples using gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). 252 pesticides extracted from surface water samples by solid-phase extraction (SPE) using liquid chromatography quadrupole-orbitrap high-resolution tandem mass spectrometry. 250 pesticide residues extracted by QuEChERS method from 103 processed fruit samples using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). 379 pesticides in human serum samples extracted by QuEChERS method using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Metrafenone in nine fresh vegetable samples using matrix solid-phase dispersion (MSPD) and HPLC-UV. Metrafenone in bitter gourd and soil samples using gas chromatography combined with an electron capture detector (GC-ECD).

Supplier: Merck

Chromolith® Phenyl HPLC columns offer greater selectivity towards aromatic ring-containing compounds than standard alkyl phases. These columns are ideal for the separation of aromatic compounds, flavonoids, fatty acids, PAH, preservatives, purines and pyrimidines.

Supplier: Merck

This Reversed phase Supelclean™ ENVI-18 are suitable for excellent for cleaning, extracting and concentrating pollutants from aqueous environmental sample (drinking, ground, waste water). Also suitable for extracting herbicides, fungicides and pesticides from waste material.

Supplier: Merck

Used as a selective enrichment medium for the isolation of Salmonella species from food and environmental specimens.

Supplier: Merck

RP-2, RP-8 and RP-18 are based on silica gel 60 modified with aliphatic hydrocarbons. The chain length, in combination with the degree of modification, defines the ability to tolerate water in the solvent system and strongly affects retention. Migration time increases in the order RP-2, RP-8 and RP-18 using the same solvent composition. RP-8 and RP-18 can be run with up to 60% water in the solvent system.

Supplier: Merck

EXtrelut® NT is a specially processed, inert, wide pore kieselguhr with a high pore volume. It has been used for quite some time within research, for the sample preparation of urine, whole blood, plasma and other biological matrices. Other applications include environmental and residue testing such as analysis of industrial, domestic and wastewater. EXtrelut® NT is supplied either pre-packed in cartridges or as a loose sorbent. EXtrelut® NT simplifies liquid-liquid extraction by replacing separation funnels. Using a single step is more efficient, saves solvent, as well as material and time, in contrast to classic funnel separation. The aqueous sample is simply applied to the EXtrelut® NT sorbent. It distributes itself over the chemically-inert matrix so acting as a stationary phase. Subsequently, elution takes place using organic solvents that are non miscible with water. All the lipophilic substances are extracted from the aqueous into the organic phase.

Supplier: Merck

This column with bonded poly(ethylene glycol) phase allows highly reproducible analyses of fatty acid methyl esters (FAMEs), specifically the omega 3 and omega 6 fatty acids. It is tested to ensure reproducible FAME equivalent chain length (ECL) values and resolution of key components.

Supplier: Merck

ZIC®-pHILIC has the same stationary phase as ZIC®-HILIC, but is instead based on a polymeric particle for enhanced pH stability. The lack of silica practically nullifies background in high sensitivity detectors such as charged aerosol used for determination of organic and inorganic ions.