Separator Polaris

On the other hand, if we are working on a separation that is nearly complete, bnt reqnires a bit of fine-tnning that cannot be accomplished with mobile phase manipnlations, we wonld select a packing that is somewhat dissimilar bnt not too different. For example, if onr primary separation was done on a Pnrospher RP18e colnmn, 111, we conld select a Hypersil Hypurity Elite, 63, a Polaris Cjg-A, 65 or a SymmetryShield RPjg column, 70, as alternatives. These alternatives wonld change the selectivity of the separation somewhat, but not too drastically. 

Fig. 5. UV chromatograms of the standard mixture separated using 2.1-mm-i.d. columns at 12 ml/min Polaris (A), Zorbax (B), Omnisphere (C), Luna (D), and Aqua (E).

MUX inlet as possible. A flow rate of 12 ml/min on eight 2.1 x 50 mm Polaris Ci8 columns was optimal for general purposes in our study. This system could analyze more than 3000 compounds per day for a gradient separation with a cycle time of 3.5 min. 

Separation of five compounds (DL, 6-OH-DL, 3-OH-DL, 7V-OH-DL, and 1-pyridine-/V-oxide-DL) was achieved using an Alliance HPLC system (Waters Corp., Milford, CA) equipped with a 2690 model pump, an autoinjector, a Polaris Cl8-A guard column (Varian Inc., Lake Forest, CA), and a Luna Phenyl-Hexyl analytical column (Phenomenex, Inc., Torrance, CA) maintained at 40°C. For robust characterization of each isomeric compound, an online HDX LC-MS method was developed. The composition of regular and deuterated mobile phases is summarized below ... 

After ore is mined at Polaris, metallurgists must separate the valuable lead- and zinc-bearing compounds from the waste or "slag." First the ore is crushed and ground with water to produce flour-like particles. Next a process called flotation is used to separate the minerals from the slag. 

LCVMS experiment was conducted with an Agilent llOOLC/MSD system. A CTC PAL autosampler from LEAP Technologies was used to introduce samples to the LC/MSD. Polaris 2000 C18 columns packed with 3 pm particles, 30 x 3 mm (i.d.) at 60°C were selected for the study. Flow rate was ImL/min, linear gradient starting form 100% water (0.05% formic acid) to 100% acetonitrile (0.05% formic acid) in 4 minutes. ESI source with positive selected ion monitoring mode (SIM) was employed to detect the corresponding ions of standard compounds. The positive ions (w/z) of 369, 371, 459, and 591 were selected to monitor Mono-Fmoc-Lysine, Bis-Cbz-Lysine, Fmoc-Cbz-Lysine, and Bis-Fmoc-Lysine separately. The mass spectra of standard compounds are shown in Figure 9.24. Four levels of calibration— 25 picomolar, 50 picomolar, 100 picomolar, and 200 picomolar of standard compounds— were used in the quantitation method. 

If polar and apolar interactions are necessary for separation (e.g., components with amino and acidic groups), phases may be encountered that show sufficient hydrophobicity but which are also capable of polar interactions because of additional polar groups on the surface, e.g., Spherisorb ODS 2, LiChrospher, Polaris C18-A, Ascends RP-Amide, Purosphere, Uptisphere UP5MM, Nucleodur Sphinx RP, Atlantis d Cjg, SynergiFUSION RP, and Acclaim PA. The fine adjusting for a better selectivity can be most effectively achieved by means of the pH of the eluent and by variation of the acid/base used [8]. A possible lack of robustness of the method has to be accepted in such systems. 

Due to their relatively higher polari the "Cailures" are easily separated after the synthesis by simple chromatography. 

---