Oasis HLB

A sensitive and selective method, which is specific for oxamyl and may be applicable to other oxime carbamates and their metabolites in heavily polluted waters, involves the use of HPLC/MS/MS. A 75-mL reservoir is attached on top of a Bond-Elut SAX (l-g/6-mL) (Varian), which is connected to an Oasis HLB (l-g/20-mL)... 

Drugs of abuse Drinking water Off-line SPE (Oasis HLB)... 

PPCPs 4 preservatives, 2 antimicrobials and 5 UV filters Surface and wastewaters SPE (Oasis HLB and Bond Elute Plexa... 

Hydrobond PS C8 ACN-MeOH (75 18 7) ESI-MS/MS shrimps and whole milk acid, cleanup with OASIS HLB SPE column (shrimps) 50-300 ng/g (milk) ... 

Sample preconcentration was performed by means of an automated on-line SPE sample processor Prospekt-2 (Spark Holland, Emmen, The Netherlands). Oasis HLB cartridges (Waters, Barcelona, Spain) were used to preconcentrate cannabi-noids present in the water samples whereas isolation of the rest of the compounds was done in PLRPs cartridges (Spark Holland). Before extraction, influent samples were diluted with HPLC water (1 9, v/v) to reduce matrix interferences and to fit some analyte concentrations, e.g., cocaine (CO) and benzoylecgonine (BE), within the linear calibration range. A sample volume of 5 mL was spiked with the internal standard mixture (at 20 ng/L) in order to correct for potential losses during the analytical procedure, as well as for matrix effects. Elution of the analytes to the LC system was done with the chromatographic mobile phase. 

Waters (see 2006-2007 Catalog, SPE products) Oasis HLB Divinylbenzene-N-vinyl-pyrrolidone copolymer Reversed phase with some hydrogen bond acceptor and dipolar reactivity Rosuvastatin (71) NSAIDs (72) fexofenadine (73) catechins (74) valproic acid (75)... 

Phenyl (Cohesive Technologies), the polymer-based Oasis HLB (Waters), the Cyclone (Cohesive Technologies), and the porous graphitized carbon-based Hypercarb (ThermoHypersil, Cheshire, UK) Cohesive s 2300 system was the HTLC component. Merck s monolithic reversed-phased Chromolith Speed ROD (RP-C18 (50 x 4.6 mm) served as the analytical column. The Oasis HLB, Cyclone TFC, and Hypercarb yielded the best retention capacity and good elution efficiency and volume. Recovery was 42 to 94% with a sample volume of 10 mL. Run time was 14 min. LODs were 0.4 to 13 ng/L for most compounds. 

A combination of chomatographic techniques such as CZE-UV, ion-pair LC-DAD and ion-pair LC-electrospray mass spectrometry was employed for the separation of polar hydrophilic aromatic sulphonates. SPE preconcentration of aromatic sulphonates was studied in detail. Sorbents LiChrolut EN, Isolute ENV+, HR-P and Oasis HLB were included in the experiments. They were activated by rinsing 7 ml of methanol followed with 3 ml of water acidified to pH 2.5 with sulphuric acid. Water samples were passed... 

Bayliss and co-workers [10] combined ultra-high flow rates, parallel LC columns, a multiplex electrospray source, and mass spectrometric detection for the rapid determination of pharmaceuticals in plasma using four narrow bore (50 mm x 1 mm, 30 pm Oasis HLB) or capillary (50 mm x 0.18 mm, 25 pm Oasis HLB) HPLC columns with large particle sizes (to avoid high system back-pressure) in parallel with a multiple probe injector and a MUX MS interface. Small sample aliquots were injected directly into the system without sample pre-treatment procedure, obtaining very low limits of quantification (from 1 to 5 ng/mL). 

C4-C6) compounds. For longer chains, less polar or non-polar SPE phases (C18 and Oasis HLB) may be applied. When an ion-pairing agent is used, that decreases the polarity of the ion-pair complex, a non-polar solvent (MTBE) may be used. Non-ionic PFASs may be extracted from the matrix by non-polar media (Cl8 SPE or hexane). Moderate polar media (Oasis HLB and Oasis WAX-SPE, a hexane-acetone mixture or acetonitrile) have also been applied for extraction of non-ionic PFASs. 

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