PEEK tubing

Material PEEK (tubes) stainless steel (housing) Tube lengths 28.50 mm 21.75 mm 15.00 mm... 

Figure 7.6 schematically shows the setup of gas introduction for the high-pressure reactor. For gas introduction, the male part of a Swagelok fitting (4 in Figure 7.6) is welded on a 1/8 in. tube of the cell lid (3 in Figure 7.6). A 1/32 in. PEEK tube...

A six-port valve was used in both manual and semi-automated SPME interfaces and PEEK tubing used to connect the HPLC system to the SPME probe. A Cohesive HTLC 2300 with dual pumps along with a Sciex API 3000 mass spectrometer was used for LC/MS/MS and a Symmetry Shield RP-18 (5 ji, 50 x 2.1 mm) for HPLC. A quaternary pump with flow switching was used for desorption chamber flushing along with MS make-up flow and a binary pump for LC/MS/MS. Acetoni-trile/0.1% acetic acid in water (90 10, solvent B) and 10 90 acetonitrile/0.1% aqueous acetic acid (solvent A) were used, with 10% B for 0.5 min ramped to 90% B in 2 min and held at this concentration for 1.5 min before returning to 10% B for 1 min at a flow rate of 0.5 mL/min. 

All required materials for a PSI system are easily accessible a flask with two ground glass joints (or one joint and an arm), rubber septum, rubber hose, a short length of PEEK tubing ( 0.5 m), a PEEK chromatography fitting (nut and ferrule) and a source of... 

Deprotection 2.1 mg Fmoc-Arg(Pbf)-OH (Merck Schuardt OHG) was dissolved in 1 ml acetonitrile (99.5%, CALEDON) in a 50 ml flask attached to a well-regulated supply of nitrogen (at 5 psi) and equipped with a septum and PEEK tubing leading to the mass spectrometer. 4 ml of trifluoroacetic acid (99.9%, CALEDON) was injected in the reaction flask. 

Silane redistribution 6 mg of (3-(methylsilyl)propyl) triphenylphosphonium hexafluorophosphate(V) (0.0121 mmol, 1 equivalent), 93 mg of Karstedt s catalyst (Pt 3.91% 0.000954 mmol, 0.8 equivalent), 6 mg of triphenylphosphine (0.0229 mmol, 1.9 equivalent) were dissolved in 20 mL of freshly distilled fluoroben-zene in a 50 mL Schlenk flask in an inert atmosphere glovebox. The flask was equipped with a septum, removed from the glovebox and installed with PEEK tubing leading to the mass spectrometer. The flask was pressurized with N2 and monitored by ESI-MS. Once a steady signal was obtained, 0.15 g of freshly distilled phenylsilane (1.39 mmol, 115 equivalents) was injected into the reaction flask. The reaction was initiated at room temperature and then was heated to reflux after 20 min to drive it to completion. 

We were also interested in how the parameter space (tube dimensions, overpressure, solvent) would affect the flow rate. For ESI-MS, flow rates of 1-50 piL min-1 cover the normal range, with 5 pi min-1 being typical. We used 0.005" i.d. PEEK tubing,... 

Fig. 6. Data from flow rate vs. overpressure experiments with different solvents and using PEEK tubing of length 0.6 m.

Note that PEEK tubing has a lower pressure rating and might not be compatible with solvents such as dimethyl sulfoxide, tetra-hydrofuran, inorganic acids, and methylene chloride. 

Simple heat transfer calculations i. e. using sources like Ref [20], indicate that even uninsulated lines are not a severe problem in most spectroscopic applications. With insulated 1/8, 1/16, and 1/32 inch stainless steel and PEEK tubing, with a flow velocity of ca. 0.1-lm s and driving force of 50 °C between... 

Beside borosilicate and fused silica capillaries, PS/DVB monoliths have been fabricated within the confines of steel and PEEK tubings [52]. In order to increase the hydrophobic character of the supports, a Friedel-Crafts alkylation reaction was used for the attachment of Cig-moieties to the polymer surface. The derivatized material was demonstrated to be more retentive and to provide more efficient peptide separations compared with the original, nonderivatized monolith. 

Figure 7.2.12 shows the principal set-up for this experiment. The column, containing the immobilized free radicals consists of an adapted PEEK tube, which fits into the flow probe below the detection cell. Figure 7.2.13 depicts a spectrum of d-n-butylphthalate recorded under the influence of a ( free-radical ) column filled with 2,2,6,6-tetramethylpiperidin-l-oxyl (TEMPO), immobilized with an aminopropyl spacer on silica. The spectrum is taken from an on-line separation of a two-compound mixture. The line width is of the same order as... 

The steel plates are made by milling and the PEEK tubes by turning and milling [39]. 

Another promising aspect of SME development has been directed toward achieving the continuous flow of an aqueous sample phase to a seemingly immobilized organic solvent drop, permitting the direct and continuous interaction of the drop with a fresh sample. The technique was called continuous-flow microextraction (CFME).11 12 In CFME, a polyetheretherketone (PEEK) tube is used as a holder for both the extraction solvent drop and the sample delivery supply. The drop (3 pL) is introduced into the PEEK tube via a valve and is pushed by the sample aliquot inside the tube until it reaches the tube outlet, where it remains (a little off-center of the tube) as a solvent drop. Then, the sample volume (typically 3 mL) is pumped continuously (from the PEEK tube) around the... 

The technique was further improved by employing a polymer coating on the polymeric fibers packed in a fused silica capillary. The coating material was based on GC stationary phases. The polymer-coated fiber-packed capillary was used as the sample loop of the LC injection valve for the extraction of phthalate esters from river water and wastewater.22 The coated-fiber extraction capillaries demonstrated a better extraction efficiency and lower limit of quantification (LOQ) than the uncoated-fiber capillaries. Also, the coated fibers were similarly packed in a PEEK tube, which was used as the injection loop or integrated in the rotor of an LC injection valve employed for the extraction of phthalates. The results clearly showed that an extraction with high selectivity could be established with an appropriate type of polymer coating.23... 

The use of ICP-MS provides some important benefits when coupled to an HPLC that separates As species prior to measurement. ICP-MS has fit-for-purpose limits of detection (LoDs) thus, analytical, not preparative, separation systems can be used with a high sampling rate ( 1 ms) in order to measure transient signals and to separately quantify closely eluting compounds from HPLC. HPLC-ICP-MS coupling can be achieved simply via a 50 cm piece of PEEK tubing without loss of peak resolution, whereas chromatographic flow rates are compatible with conventional ICP-MS spray chambers. 

The Sapphire HPNMR Tube. First introduced by Roe in the 1980s, these have become popular and are in widespread use. More recently, a variant using PEEK tubes has appeared. ... 

Always use a blast shield around pressurized tubes to protect the operator (also applies to PEEK tubes). 

The HPLC is connected by red polyether ether ketone (PEEK) tubing to the NMR flow cell which is inside the magnet. With shielded cryomagnets or ultra-shielded magnets the HPLC can be as close as 30-50 cm to the magnet versus... 

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