Columns Alltech

The cracking of diphenylmethane (DPM) was carried out in a continuous-flow tubular reactor. The liquid feed contained 29.5 wt.% of DPM (Fluka, >99%), 70% of n-dodecane (Aldrich, >99% solvent) and 0.5% of benzothiophene (Aldrich, 95% source of H2S, to keep the catalyst sulfided during the reaction). The temperature was 673 K and the total pressure 50 bar. The liquid feed flow rate was 16.5 ml.h and the H2 flow rate 24 l.h (STP). The catalytic bed consisted of 1.0 g of catalyst diluted with enough carborundum (Prolabo, 0.34 mm) to reach a final volume of 4 cm. The effluent of the reactor was condensed at high pressure. Liquid samples were taken at regular intervals and analyzed by gas chromatography, using an Intersmat IGC 120 FL, equipped with a flame ionization detector and a capillary column (Alltech CP-Sil-SCB). 

Procedure Prepare a series of THI-DNPH Standard Solutions serially diluted from the Stock THI-DNPH Solution. Pipet 1, 2, and 5 mL, respectively, of the Stock THI-DNPH Solution, into separate 10-mL volumetric flasks, and dilute to volume with absolute, carbonyl-free methanol. Prepare a standard curve by injecting 5 p-L of the Stock THI-DNPH Solution, and the serially diluted THI-DNPH Standard Solutions into a 250-mm x 4-mm (id), 10-lm LiChrosorb RP-8 HPLC column (Alltech Associates, Inc., or equivalent) fitted with an ultraviolet detector set at 385 nm. The mobile phase is 50 50 (v/v) methanohO.l M phosphoric acid. Inject 5 pL of sample into the column. Adjustments in the mobile phase composition may be needed as column characteristics vary among manufacturers. At a mobile phase flow rate of 2 mL/ min and column dimensions of 250 x 4.6 mm, elute THI-DNPH at about 6.3 0.1 min. Measure the peak areas. Calculate the amount of THI in the sample from the standard curve. (For THI limits greater than 25 mg/kg, prepare a series of Standard THI-DNPH Solutions in a range encompassing the expected THI concentration in the sample.)... 

Lioid Analysis. Fatty acids in lipids were first converted to methyl esters by reacting them with METH-PREP II (ALLTECH-Applied Science, Deerfield, IL) and then analyzed by GC. Methyl esters were analyzed by a Tracer GC equipped with a flame ionization detector (Tracer, Austin, TX) and a RSL 500, 30 meter FSOT column (ALLTECH, Deerfield, IL). Details of GC analysis conditions can be found elsewhere (11). 

Guard column Alltech Direct Coimect packed with p Bondapetk CIS Column 250 X 4.6 5 pm Ultrasphere CIS... 

Either glass (Kontes in Vineland, NJ 2.5 cm inner diameter, 15.0 cm long) or stainless steel columns (Alltech in Deerfield, IL 2.5 cm inner diameter, 7.0 cm long) were incrementally packed with the air-dried soil (<2mm) to obtain a uniform bulk density. The packed columns were slowly wetted from the bottom with an electrolyte solution of 5 mM CaCl2 to estabfish saturation. Approximately 100 column pore volumes of electrolyte solution were pumped through the column prior to the transport study. 

The reactor feed or effluent was analyzed using a Varian 3300 gas chromatograph using a seven foot 0.19% picric acid on Graphpac packed column (Alltech) and a FID detector. The column was held at 50°C for four minutes and then heated at a rate of 25°C/min to a final temperature of 100°C and maintained until all C5 species were eluted. A sixteen port Valeo valve rotated by an electric motor was used to collect samples at short intervals immediately following introduction of the feed to the reactor. 

Only one major compound (SF-X) was present in the estrogenically active fractions, and this was isolated using semipreparative HPLC. The principles of separation are the same as for qualitative HPLC (see Section 25.4.1.2), with the difference that higher amounts of material can be loaded onto the ODS-column (Alltech, Econosil, Cig lOp, 250x22mm). For the identification of SF-x, a combination of spectroscopic techniques was used. Electrospray ionization in the mass spectrometer (HPllOO LC/MSD, Hewlett-Packard) with positive ionization mode gave a pseudo-molecular ion with m/z=439. H-NMR, C-NMR, DEPT, HMQC, and COSY spectra were recorded on a Varian-300 (300MHz) spectrometer. Analysis of the COSY spectram showed the presence of a lavandulyl (5-methyl-2-isopropenyl-hex-4-enyl) side chain. From the HMQC spectrum and a DEPT experiment, it appeared that SF-x possesses a disubstituted flavanone skeleton. 

Products were extracted from the zeolite in an organic solvent, such as acetonitrile. GC (gas chromatography) with an FID detector and a 5% phenyI/95% methylpolysiloxane capillary column (Alltech, SE-54) was used for product identification. If available, standards of the products were injected separately to determine retention times and response factors. 

Chromatography equipment high-performance liquid chromatography (HPLC) and coupled electro-spray ionization mass spectrometer, Jordi PolarPac WAX 10,000A 300 X 7.8 mm column (Alltech, Deerfield, IL), and HiLoad 26/60 Superdex 200 gel filtration column (Amersham Pharmacia Biotech, Piscataway, NJ). 

Figure 3.104 Separation of mono-, di-, and trivalent anions with a combined carbonate-based composition and concentration gradient. Column Alltech Novosep A-1 column dimensions 100 mm x 4.6 mm i.d. eluent ...

Fig. 3-68. Separation of mono-, di- and tri-valent anions with a combined carbonate-based composition and concentration gradient. — Column Alltech Novosep A-1 (100 mm X 4.6 mm i. d.) eluant 1.7 mmol/L NaHC03 linearly in 5 min to 2.8 mmol/L NaHCOs + 2.2 mmol/L Na2C03 + 0.22 mmol/L p-cyanophenol, then to 5 mmol/L NaHC03 + 5 mmol/L Na2C03 + 0.5 mmol/L p-cyanophenol in 5 min, then to 10 mmol/L Na2C03 + 1 mmol/L p-cyanophenol in 5 min flow rate 1.5 mL/min detection suppressed conductivity solute concentrations 5 mg/L acetate (1),...

Fig. 7.19. METSCAN determination of 450 ppb Cu(dedtc>2 and 250 ppb Ni(dedtc)2. Solvent, 75% acetonitrile 25% 0.02 M acetate buffer (pH 6.0), 0.01 M NaNOa. Flow rate, 0.2 ml min . Ityection volume, 5 /tl. Column, Alltech 5 /tm Adsorbosphere (25 cm X 2 mm). Detection potential, +0.8 V vs Ag/AgCl. Temperature, 20°C. Reproduced by courtesy Anal. Chem. 60 (1988) 1357.

---