Filters liquid chromatography

Lab method using porous polymer adsorption tube and thermal desorption with gas chromatography Lab method using porous polymer diffusive samplers with thermal desorption and gas chromatography Lab method using pumped acid-coated filters, desorption and liquid chromatography... 

Hydrazine in air Lab method using sampling either onto acid-coated glass-fibre filters followed by solvent desorption or into specially constructed impingers. Linal analysis by derivatization and high performance liquid chromatography 86... 

Commercial grades of PVP, K-15, K-30, K-90, and K-120 and the quaternized copolymer of vinylpyrrolidone and dimthylaminoethylmethacrylate (poly-VP/ DMAEMA) made by International Specialty Products (ISP) were used in this study. PEO standard calibration kits were purchased from Polymer Laboratories Ltd. (PL), American Polymer Standards Corporation (APSC), Polymer Standards Service (PSS), and Tosoh Corporation (TSK). In addition, two narrow NIST standards, 1923 and 1924, were used to evaluate commercial PEO standards. Deionized, filtered water, and high-performance liquid chromatography grade methanol purchased from Aldrich or Fischer Scientific were used in this study. Lithium nitrate (LiN03) from Aldrich was the salt added to the mobile phases to control for polyelectrolyte effects. 

One example of normal-phase liquid chromatography coupled to gas chromatography is the determination of alkylated, oxygenated and nitrated polycyclic aromatic compounds (PACs) in urban air particulate extracts (97). Since such extracts are very complex, LC-GC is the best possible separation technique. A quartz microfibre filter retains the particulate material and supercritical fluid extraction (SPE) with CO2 and a toluene modifier extracts the organic components from the dust particles. The final extract is then dissolved in -hexane and analysed by NPLC. The transfer at 100 p.1 min of different fractions to the GC system by an on-column interface enabled many PACs to be detected by an ion-trap detector. A flame ionization detector (PID) and a 350 p.1 loop interface was used to quantify the identified compounds. The experimental conditions employed are shown in Table 13.2. 

The reaction mixture is cooled, diluted with 100 mL of sat. aq NaCI and extracted with four 50-mL portions of Ei,0. The combined ethereal extracts are washed with 50 ml. of sat. aq NaCI, dried, filtered and concentrated to a volume of a few milliliters. 20 ntL of petroleum ether arc added to precipitate the soluble salts. The mixture is filtered through a silica gel column (petroleum ether)and purified by medium-pressure liquid chromatography yield 360 mg (65%). 

Short Term Noise consists of base line perturbations that have a frequency that is significantly higher than the eluted peak. Short term detector noise is not often a serious problem m liquid chromatography as it can be easily removed by an appropriate noise filter without affecting the profiles of the peaks. Its source is usually electronic, originating from either the detector sensor system or the amplifier. 

Figure 2, Block diagram of a liquid chromatograph. A, solvent reservoir B, filter C, pump D, pulse dampener (optional) E, pre-column (used only in liquid-liquid chromatography) F, pressure gauge G, infector H, column I, detector J, fraction collector K, recorder or oth readout device.

J. Chen and S.C. Rutan, Identification and quantification of overlapped peaks in liquid chromatography with UV diode array detection using an adaptive Kalman filter. Anal. Chim. Acta, 335(1996) 1-10. 

A form of flux calcined silica of low surface area used mainly as a filter aid and inert support in gas and liquid-liquid chromatography. 

Soekhoe, U. and Kerstens, H.J. (1995) Determination ofPropoxur, Methiocarb, and Tinopal on Gloves, Filters, and Leaves by High Performance Liquid Chromatography, Report DATV/BT/076, TNO Nutrition and Food Research Institute, Department of Occupational Toxicology, Rijswijk, The Netherlands (in Dutch). 

Another important issue to take into account is the low solubility of many of the UV filters, which makes totally necessary to work with unit samples due to the indispensable solubilization step before the analytical determination by high performance liquid chromatography (HPLC). 

Related substances. Carry out the method for liquid chromatography, Appendix III D, using the following solutions. For solution (1) shake a quantity of the gel containing 50 mg of miconazole with 25 mL of methanol for 30 min, add sufficient methanol to produce 50 mL and filter through a glass microfibre (Whatman GF/C is suitable). For solution (2) dilute 1 volume of solution (1) to 100 volumes with methanol and dilute 5 volumes of the resulting solution to 20 volumes with methanol. Solution (3) contains 0.0025% (w/v) of miconazole nitrate BPCRS and econazole nitrate BPCRS in methanol. 

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