Column symmetry

HPLC condition — A Waters reversed-phase HPLC column (Symmetry Shield RP Cl8, 5 pm, 2.1 x 50 mm) was used in conjunction with a Regis SPS guard column (ODS, 5 pm, 100 A,... 

FIGURE 2.5 Separation of flavanoids on a classical RP and on a shielded phase. Columns Symmetry CIS symmetry shield RPIS (150x4.6mm). Mobile phase ACN/lOmM PO4 buffer pH 3, 30/70 v/v, 40°C. 

FIGURE 2.12 Influence of pH value on retention of basic analytes. Samples A,A-dimethyl aniline A-ethyl aniline. Column symmetry shield CIS mobile phase acetonitrile-20 mM phosphate buffers-water, 35-35-... 

FIGURE 2.13 Influence of ionic strength on solute retention. Analytes 1, uracil 2, phenol 3, procaine 4, propranolol 5, toluene. Column Symmetry RP C8 150 x4mm. Mobile phase methanol-phosphate buffer pH 7 upper chromatogram ImM lower chromatogram 20mM. 

FIGURE 2.16 Influence of an organic modulator on selectivity. Comparison between acetonitrile and methanol. Isoelutropic conditions for ethyl benzene. Column Symmetry C8, 150 x4mm. Mobile phase methanol-water. 55-45, v-v. Acetonitrile-water, 42-58, v-v. Solntes 1, thiourea 2, aniline 3, phenol 4, o-toluidine 5, m-toluidine 6, -tolnidine 7, V,V-dimethyl aniline 8, benzoic acid ethylester 9, tolnene 10, ethyl benzene. 

FIGURE 2.18 Separation of polar and acidic solutes on a classical RP and on shield phases. Columns Symmetry C8 and symmetry shield C8. Mobile phases 20% ACN, 10% HjO, 70% lOmM phosphate buffer pH 3 (v-v-v). 30% MeOH, 70% lOmM phosphate buffer pH 3 (v-v). Samples 1, 4-hydroxyisophthalic acid 2, acetylic salicylic acid 3, salicylic acid 4, phenol 5. methylparaben 6, dimethylphthalate. 

FIGURE 2.22 Influenceof a pH value on retention of benzyl amine. Column Symmetry C8. Mobile phase acetonitrile-20mM phosphate buffers-water 35-35-30, v-v-v. Temperature 40°C benzylamine 125 ppm, injection 10 aL. 

Rocuronium bromide Verapamil (i.s.) Column Symmetry Human plasma Shield RP18 cartridge (50 x 2.1 mm) Detector ESI-MS Mobile phase linear gradient from 10% to 90% of ACN in water containing 0.1% TFA/ applied in 15 min. Column was then washed for 3 min at final gradient condition and set back to initial condition in 1 min and equilibrated for 5 min Single ion recording Rocuronium bromide m/z 265 and m/z 529 Verapamil m/z 455... 

LC-MS/MS System Used and Analytical Conditions A Shimadzu liquid chromatography system was used (Shimadzu Scientific Instruments, USA). The system consisted of a Shimadzu SCL-10A VP system controller with four LC-10AD VP pumps. A Perkin-Elmer series 200 autosampler, equipped with a cool-tray (Perkin Elmer, Norwalk, CT, USA) was used for sample injection. Moreover, a six-port switching-valve was implemented in order to switch between an extraction column and the analytical column. Samples were injected onto the extraction column (Oasis HLB column). After a short extraction/equilibration time of 0.3 min, the samples were eluted from the extraction column onto the analytical column (Symmetry C18) (Figure 1). 

Deksametazon, prednisone, prednisolone, dexamethasone, cortisol/semm HPLC MS MS Column Symmetry Cig (30 x 2.1 mm, 3.5 pm) Mobile phase MeOH 5 mM acetate buffer, pH 3.25 (gradient elution) Detection MS/MS, ionization ESI Extraction SPE/column Oasis HLB/elution MeOH LOD 0.20-0.58 ng/mL LOQ 5.4-10.7 ng/ mL [78]... 

Fig. 2 HPLC chromatogram of phenolic acids using (A) ODS Hypersil column, (B) Symmetry Cig column and isocratic elution. Conditions (A) column ODS Hypersil (200 x 4.6 mm, 5 pm), mobile phase methanol-water-acetic acid (25 75 1), flow-rate 1 mL/ min (B) column Symmetry Cig (250 x 4.6 mm, 5 pm), mobile phase methanol-0.001 M phosphoric acid (23 77), flow-rate 1 mL/min. Peaks 1) protocatechuic acid 2) chlorogenic acid 3) p-hydroxybenzoic acid 4) vanillic acid 5) caffeic acid 6) syringic acid 7) p-coumaric acid 8) ferulic acid. (From Refs. [7] (A) and [8] (A).)...

Fig. 3 HPLC analysis of phenolic acids using (a) Separon SGX Cig column and (b) Symmetry Cig column and gradient elution. Conditions (A) column Separon SGX Cig (250 x 4.6 mm, 7 pm), mobile phase methanol-water (pH = 2.5, adjusted with formic acid), linear gradient from 15% methanol to 75% methanol in 40 min, flow-rate 0.5 mL/min (B) column Symmetry Cig (150 x 3.9 nm, 5 pm), mobile phase and flow-rate same as in (a). Peaks 1) gallic acid, 2) protocatechuic acid, 3) catechin, 4) caffeic acid, 5) sinapic acid, 6) rosmarinic acid.

Fig. (7). UV -profile (268nm) of 20 cytokinin standards. Tlie standard mixture, containing 10 pinol of each derivative was injected on HPI.C chromatographie column Symmetry CIS, 150 mm x 2.1 mtn,. 5 pm (A) and LTPLC chromatographic column BEH CIS, 50 mm x 2.1 mm, 1.7 pm (B).

Figure 2.4 Experimental and calculated band profiles of benzyl alcohol (a) and phenylethanol (b). Sample volume 0.5 mL, Co = 25 g/1. Column, Symmetry-Cig mobile phase, methanol and water (1 1, v/v) flow rate, 1 ml/min. Experimental profiles (circles), profiles calculated with a rectangular injection (dashed line) and with the experimental injection profiles (solid line). Reproduced with permission from 1. Quinones et ah, Anal. Chem., 72 (2000) 1495 (Fig. 6). 2000, American Chemical Society.

Conditions (A) column Separon SGX Ci8 (250 X 4.6 mm, 7 xm), mobile phase methanol-water (pH = 2.5, adjusted with formic acid), linear gradient from 15% methanol to 75% methanol in 40 min, flow-rate 0.5 ml/min (B) column Symmetry Cig... 

System Waters Alliance System with 996 PDA detector Column Symmetry C8, 3.9 x 150 mm Column Temperature 50°C... 

---