PTFE filter

Figure 8 shows a typical F4PLC chromatogram of the tablet extract illustrating the complexity of the sample, which contains numerous natural components, excipients and additives. During the SP method development, it was found that extraction with a neutral aqueous buffer was problematic due the loss of one of the active ingredients by hydrolysis. The use of the PTFE filter was also important because this hydrolysis product, which is highly hydrophobic, was absorbed by nylon filters under the filtration conditions. 

QhEChERS 3 g homogenized sample mixed with water, addition of ACN, NaCl, an. MgS04, centrifugation Clean-up Mix with PSA sorbent, an. MgS04, Cl8, graphitized carbon black, 0.45 pm PTFE filtering... 

Diborane in air may be analyzed by passing air through a PTFE filter and oxidizer-impregnated charcoal. It is oxidized to boron and desorbed with 3% H2O2. Boron is measured by plasma emission spectrometry or ICP emission spectrometry (NIOSH. 1984. Manual of Analytical Methods, 3rd ed. Cincinnati, OH National Institute for Occupational Safety and Health). Boron hydrides can be analyzed by FTIR techniques. 

On S S276 ANTU 0.3 PTFE filter Methanol HPLC 0.128-0.76... 

A S294 Paraquat 0.5 PTFE filter Water HPLC 0.256-1.03... 

A S300 Rotenone 5 PTFE filter Acetonitrile HPLC 1.16-11.1... 

A S381 Sodium hydroxide 2 PTFE filter HC1 NaOH back-titration 0.76-3.9... 

A 304 (S154) o-Chrorobenzylidene aalononitrile (0CBM) 0.4 PTFE filter/ Tenax GC... 

A 297 (S390) Dlbutyl phosphate 5 PTFE filter... 

Filter Methods. The filters most commonly used were mixed-cellulose ester (MCE), glass fiber (GF), and polytetrafluoroethyl-ene (PTFE). Glass fiber and PTFE filters were used almost... 

A Kjeldahl flask was charged with ,/V -dimethyl-1,6-diaminohexane (5.75 mmol) dissolved in 10 ml of THF and then treated with the dropwise addition of -butyl-lithium (5.75 mmol) while vigorously stirring. This solution was then treated with chlorotrimethylsilane (5.75 mmol) and stirred at ambient temperature for 30 minutes and then filtered off through a poly(tetrafluoroethylene) (PTFE) filter and 15 mL of the filtrate charged into a 150-ml glass bottle. This aliquot was then treated with tetramethylethylene diamine (4.23 mmol) and n-butyllithium (4.23 mmol) and used immediately as a polymerization initiator. 

Methodology. Teflon filters exhibit the lowest HN03 retention of those in common use (12). Fluoropore (Millipore Corporation) and Zefluor PTFE filters (Gelman Sciences) of 0.5- to 2- xm pore size, are frequently used as prefilters in the filter pack method (FPM). With 47-mm-diameter filters, flow rates with the FPM from 10 to 20 L/min are typical. The 2- xm pore size Zefluor filter exhibited 97% efficiency for 0.035- xm particles at a face velocity of 33 cm/s, with a pressure drop of 1.0 cm Hg (1.3 kPa) (33). 

Filter hydrolysate using glass syringe fitted with a Swinney stainless steel 13-mm filter unit and a 0.22- im PTFE filter into a clean borosilicate glass tube. After each sample has been filtered, discard the PTFE filter and wash the syringe and filter unit 6 times in Milli-Q-purified water to ensure there is no carryover from one sample to another. 

Filter the hydrolysate using glass syringe fitted with aSwinney stainless steel 13-mm filter unit and a 0.22-pm PTFE filter into a clean borosilicate glass tube. 

Filter a sample or blank (deionized or distilled water) with a PTFE filter membrane or other material to achieve clarity. 

One-milliliter aliquots of pesticide standards should be mixed with 5 ml acetonitrile, and 1ml aliquots of the mixture passed through the PTFE filters and C18 cartridges. 

PTFE filter is used to remove boron-containing particulates. Use of mixed cellulose ester membrane prefilters is not recommended. 

Three copolymers, PNIPAM-co-l.O-MACA, PNIPAM-co-2.9-MACA and PNIPAM-co-4.9-MACA were used. Their weight-average molar masses (Mw) are 9.4 x 105, 8.3 x 105 and 6.5 x 105 g/mol, respectively. In order to avoid possible interchain association, we kept each dilute solution in a refrigerator for at least one day to ensure a complete dissolution. The solution was clarified by a 0.45 Millipore (Hydrophlic Millex-LCR, PTFE) filter and then kept in a refrigerator again for a few days before LLS measurements. 

Sample Preparation Transfer about 0.1 g of sample, accurately weighed, into a 4-dram vial. Add between 0.010 to 0.015 g of diphenyl ether, accurately weighed, 10 mL of toluene, and 5 drops of 10% sodium hydroxide solution cap the vial and shake well. Allow the vial to stand until the caustic layer settles to the bottom, and filter the neutralized sample through a 0.45-p.m polytetrafluoroethylene (PTFE) filter, or equivalent. 

Figure 3.1 Simple air sampling cartridge with open-face particle filter (a) O-ring seal (b) filter holder (c) stainless steel support screen (d) particle filter (e) PTFE filter gasket ...

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