Phenyl hexyl column

Koal et al. (2004) measured four immunosuppressants (cyclosporine A, tacrolimus, sirolimus, and everolimus) in whole blood samples from transplant recipients. The samples were treated first with a protein precipitation step. The supernatant was extracted with a Poros Rl/20 perfusion column (30 x 2.1 mm, 20 tm, Applied Biosystems, Darmstadt, Germany) online. A Luna phenyl hexyl column (2 x 50 mm, Phenomenex, Schaffenburg, Germany) was used for separation. The total run time was 2.5 min. The lower limit of quantitation was 10 ng/mL for cyclosporine A and 1 ng/mL for the other three analytes. 

RP-HPLC has also been used for the analysis of flavan-3-ols and theaflavins during the study of the oxidation of flavan-3-ols in an immobilized enzyme system. Powdered tea leaves (20Qmg) were extracted with 3 X 5 ml of 70 per cent aqueous methanol at 70°C for lQmin. The combined supernatants were filtered and used for HPLC analysis. Flavan-3-ols were separated in a phenyl hexyl column (250 X 4.6 mm i.d. particle size 5 /im) at 30°C. Solvents A and B were 2 per cent acetic acid in ACN and 2 per cent acetic acid in water, respectively. Gradient elution was 0-lQmin, 95 per cent B 10-4Qmin, to 82 per cent B to 40-5Qmin 82 per cent B. The flow rate was 1 ml/min. Theaflavins were determined in an ODS column (100 X 4.6 mm i.d. particle size 3pm) at 30°C. The flow rate was 1.8 ml/min and solvent B was the isocratic mobile phase. The data demonstrated that flavan-3-ols disappear during the oxidation process while the amount of theaflavins with different chemical structures increases [177],... 

Figure 4-24. Benazepril hydrochloride SS and SR isomers on Phenomenex phenyl-hexyl column, 150 x 4.6 mm, 70% ammonium phosphate buffer (wpH 2.1-7.1), 30 v/v% MeCN, ImL/min, 25°C. (Courtesy of Rajinder Singh.)...

The simultaneous determination of risperidone and its 9-hydroxy metabolite by LC-MS was reported [44]. The analytes were extracted from plasma (adjusted to pH 10.5) by LLE with 15% dichloromethane in pentane. LC separation was achieved on a 50x4.6-mm-ID phenyl-hexyl column (5 gm) using an isocratic mobile phase consisting of 50% acetonitrile, 45% methanol, and 5% 0.15 mmol/1 aqueous ammonium acetate (AmOAc). Positive-ion ESI-MS was applied in SRM mode. Good linearity was obtained between 0.1 and 100 ng/ml. The LQQ was 0.1 ng/ml. The method was applied to study pharmacokinetic parameters and for therapeutic drag monitoring in patients. 

Blank, calibrator, control, and patient whole-blood samples (50 /iL) were transferred into 1.5 mL conical test tubes, mixed with 100 /xL of the IS, vortexed for 10 sec, and centrifuged at 13,000 g for 5 min. Twenty-five microliters of supernatant were injected onto a Cohesive Technologies Cyclone polymeric turbulent flow column (50 x 1 mm, 50 /flushed with a mixture of methanol and water (10 90 v/v) at a flow of 5 mL/min. Column switching from the TFC to HPLC systems was via a Cohesive Technologies system. The analytical column was a Phenomenex Phenyl-Hexyl-RP (50 x 2.1 mm, 5 /.mi). The mobile phase consisted of methanol and ammonium acetate buffer (97 3 v/v). The buffer was 10mM ammonium acetate containing 0.1% v/v acetic acid. The flow rate was 0.6 mL/min. 

A similar HPLC technique was employed for the investigation of the persistence of MG in juvenile eels (Anguilla anguilla). Extracts were separated in phenyl-hexyl and octyl silica columns (both 50 X 4.6 mm i.d. particle size 3 jun) in series. The mobile phase was composed of 60 per cent ACN and 40 per cent 0.05 M ammonium acetate buffer (pH = 4.5). The flow rate was 0.6 ml/min and analytes were detected at 620 nm. The concentrations of MG and LMG are compiled in Table 3.16. The data prove that this HPLC method can be used for the investigation of the persistence of MG and LMG in animal tissues [106],... 

Figure 1 Separation of impurities A, B, and C from the peak of interest (P) using seven different HPLC systems. Reprinted from [14], copyright 2004, with permission from Elsevier. (For each system the column temperature is 30°C, the detector is UV 254 nm and the gradient is a 60-min gradient from 5% to 95% organic modifier. Ml column 250 X 4.6 mm i.d. 5 pm Kromasil C4, mobile-phase acetonitrile/0.1% trifluoroacetic acid [pH 1.9] M2 column 100X4.6 mm i.d. 5 pm Luna phenyl-hexyl, mobile-phase acetonitrile/0.1% acetic acid adjusted to pH 3.5 with ammonium hydroxide M3 column 100 X 4.6 mm i.d. 5 pm Luna phenyl-hexyl, mobile-phase acetonitrile/10 mM ammonium acetate [pH 7.0] M4 column 100 X 4.6 mm i.d. 5 pm Luna phenyl-hexyl, mobile phase THF/10 mM ammonium acetate adjusted to pH 5.0 with glacial acetic acid M5 column 150 X 4.6 mm i.d. 3 pm Spherisorb ODSl, mobile-phase methanol/10 mM ammonium acetate [pH 7.0] M6 column 150 X 4.6 mm i.d. 5 pm Monitor Cl8, mobile-phase methanol/0.1% acetic acid adjusted to pH 3.5 with ammonium acetate M8 column 100 X 4.6 mm i.d. 4 pm YMC J Sphere ODS H80, mobile-phase acetonitrile/0.1% formic acid [pH 2.1] [M7 is a variation on the M8 gradient and is not shown].)...

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 ... 

The samples (50 (jul) were analysed on a Hewlett Packard 1050 DAD system upgraded with a 1090 DAD optical bench. The column was a Luna 5 j,m phenyl-hexyl, 250 mm x 4.6 mm maintained at 30 °C. The flow rate was 1 ml min-1 using a gradient elution of acetonitrile and water as follows ... 

FIGURE 144 (A) Achiral- and (B) chiral-method screen strategies. (A) Platform 1 (HPLC-1) uses two different mobile phases, one is acidic (mobile phase 1) and another is neutral-to-basic (mobile phase 2) to screen on two columns, a classic reverse-phase C-18 and a special polar group-embedded C-18 (AQ). Platform-2 (HPLC-2) uses one mobile phase (pH is usually acidic) to screen four different columns of wide range of polarity (PFP fluorinated, and Phen phenyl-hexyl phases). Platform-3 (SFC) uses three different mobile phases and five different columns (PYD 2-ethylpyridine, BENZ benzamide). Platform-4 (CE) uses two different mobile phases. (B) AD, OJ, OD, AS are different polysaccharide-based chiral stationary phases. 

Another advantage is the improved tolerance of these materials toward highly contaminated samples. These columns do not become contaminated as easily as similar particulate materials. The disadvantages, however, should also be mentioned. The columns are limited to a pressure of 200 bar as the monolithic silica rods are seated in a PEEK hull. Furthermore, only a few different selective stationary phases are available. Although recently a few additional bondings such as Phenyl-Hexyl and Cyanopropyl have been announced, only two companies so far... 

Analytical column SymmetryShield RP8 Luna Phenyl-Hexyl... 

Fig. 4.10 Calibration curves for ICSn (R=butyl, phenyl, c-hexyl) separated by HPLC-GFAA with strong cation exchange (SCX) columns using Me0H/H20/NH40Ac eluents are shown with respective correlation...

The AOAC-CIPAC method (1983) adopts a 1.22m x 4 mm i.d. glass column with 5% OV-J01 or OV-1 on 80/100 mesh Chromosorb W (HP), using dicyclo-hexyl phthalate as IS. The 1993 edition of the British Pharmacopoeia lists a GLC method using a 1.0m X 4mm glass column, packed with 3% of phenyl-methyl-silicone fluid (OV-17) on an acid-washed, si 1 anized diatomaccous support (100/120 mesh), with tetraphenylelhylenc 0.2% as IS. A typical GLC chromatogram is shown in Fig. 4.6. 

Suitable samples for reversed-phase columns packed with C, , C, phenyl, or hexyl packings are aromatic hydrocarbons such as toluene, xylene, cumene, naphthalene, acenaphthene, and anthracene and long-chain phthalates such as dihexyl phthalate or dioctyl phthalate. These samples give large retention factors and symmetric peaks with acetonitrile/water mobile phases of high acetonitrile content Typical mobile phases contain 50-70% acetonitrile. The... 

To 2 mL THF containing 2.2 mmol hexamine and 28 mL A,Ai-diisopropylamine (0.2 mmol) at 0°C under nitrogen atmosphere was added 1.51 mL 1.58 M BuLi in hexane solution (2.4 mmol) dropwise. After being stirred for 15 min, a solution of 2.0 mmol 2-phenyl cyclohexanone in 2.0 mL THF was added, and the mixture was stirred for 30 min at 0°C and at room temperature for 5 h. The reaction was then quenched with 25 mL 1 M HCl, and the mixture was extracted with EtOAc (3 x 20 mL). The organic layer was dried over Na2S04 and concentrated. The residue was purified by column chromatography on silica gel to give 86% Ai-hexyl-6-phenylhexanamide. 

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