Retention time fused-silica capillary columns

Under these chromatographic conditions, the CS2 retention time is about 3 min on a fused-silica capillary column and about 2 min on a Teflon Chromosil 330 packed column. 

Lee et al. [30] described a micellar electrokinetic capillary chromatographic method for the determination of some antiepileptics including valproic acid. They used a fused silica capillary column (72 cm x 50 pm) and SDS as the micellar phase and multiwavelength UV detection. Reaction conditions, such as pH and concentration of running buffer were optimized. Solutes were identified by characterizing the sample peak in terms of retention time and absorption spectra. Recoveries were 93-105%. 

For qualitative analyses, the GC system was equipped with a J W Scientific HP-5 or a Supelco Simplicity 1 fused-silica capillary column. Injector and detector temperatures were set at 220 °C and 240 °C respectively the oven temperature was programmed from 60 to 230 °C at 40 °C min V Helium was employed as carrier gas (1 mL min ). Compound identification was based on a comparison of mass spectra with those of synthetic racemic and enantiomeric-enriched samples. The retention times for tetralin, 1-tetralol and 1-tetralone were 5.6 min, 6.5 min and 6.6 min respectively. 

Analytical. Samples were chromatographed on a Hewlett-Packard 5880A gas chromatograph which was fitted with a 30M fused silica capillary column (DBS) and an automatic sampler. The GC was interfaced to a Hewlett-Packard 3354 Laboratory Automation System (LAS). Raw data was automatically transferred to the LAS where peaks were selected by retention time, integrated and stored in a processed file. Processed data was then transferred... 

GC column a fused silica capillary column, such as DB-5, SPB-5, or equivalent the compound eluted relatively at a long retention time. 

For positive identifications by GC/MS, the full mass spectrum of a tentatively identified component was compared to the mass spectrum of an authentic sample. If the spectra were identical, within experimental error, and if the gas chromatographic retention times of standard and unknown components on a 30-meter SE-54 fused silica capillary column agreed within two seconds, the identification was considered positive. When the amount of material present was insufficient for detection using full scan GC/MS techniques, the more sensitive single and multiple ion monitoring techniques were employed. Confirmation in these cases consisted of coincidences of retention times of mass chromatograms of the unknown and of the authentic sample. For chlorinated materials, the molecular ions contained additional information about the chlorine isotope distribution. Confirmation in those cases included the correct isotope... 

Chlorinated compounds were analyzed by gas chromatography-electron capture detection (GC-ECD) on a Vista 44 GC System equipped with a DB-1701 fused silica, capillary column (30 m, 0.25 inn I.d. J W Scientific). Helium and nitrogen were the carrier and make-up gases, respectively. The Injector and detector temperatures were 260 C and 285 C. The column oven was temperature programmed from 65°C (held 1 min) to 230°C at 25°C/min, held at 230°C for 7.4 min, and then heated to 245°C at lO C/min. The linear velocity at maximum temperature was ca. 50 cm/sec. All GC Injections In this study were splltless with the Inlet purged 1 minute after Injection. The retention time of decachloroblphenyl under these conditions was approximately 26 minutes. 

A 30 to 50 m fused silica capillary column with a 5% phenyl-95% methyl-polysiloxane chemically bonded stationary phase (DB-5, CP Sil-8, HP Ultra 2, PTE-5) is very often used, while several oven temperature programs have been applied for PCB analysis. Table 18.7 shows a selection of combinations of column lengths, stationary phases, oven temperature programs, and detectors. Table 18.8 shows the stationary phase composition of the capillary columns listed in Table 18.7. Cochran et al. " have reviewed the most recent developments for the capillary GC of PCBs with detailed lists of PCB retention times on common capillary columns. 

Gas chromatographic conditions are as follows Column OB-210 (30 m x 0.318 mm X 0.5 pm, fused silica capillary column), column temp 1 100X, time 1 > 5 min, rate = 20°/min temp 2 = 200 C, time 2 = 7 min, injector temp 250 C, detector temp 250°C, inlet P, 24 psi, retention times trans-stilbene 11.4 min, trans-stilbene oxide 11.9 min. 

Separation of fatty add methyl esters was achieved on an Agilent J W DB-23 fused silica capillary column (60 mxO.251 mm i.d., 0.25 pm Agilent, Santa Clara California, USA). The oven temperature program was initially 120 °C for 5 min, raised to 180 °C at 10 °C min-i, then to 220 °C at 20 °C min-i and finally isothermal at 220 C for 30 min. The injector and detector temperatures were maintained at 220 and 225 °C, respectively. The carrier was high purity helium with a linear flow rate of 1 ml min i and spht ratio 1 50. Fatty add methyl esters were identified using fatty add methyl esters standards (Sigma, St Louis, Mont, USA) by comparison of the retention times of the relative peaks (Nasopwulou et aL, 2011). 

Retention time obtained on a crossed-linked fused silica capillary column of the SE-54 type with temperature program 100°C for 1 min. then 30°C/min to 220 C. Injector 250°C. 

In contrast to clinical samples, bulk formulations provide more than an adequate amount of sample for analysis. Derivatization procedures are really unnecessary for unequivocal identification if adequate resolution can be achieved. Figure 16.7 shows the analysis of a mixture of 19 anabolic steroids on a 30-m X 0.25-mm-i.d. Rtx-5 (0.1-p.m film thickness) fused-silica capillary column. Table 16.5 lists the corresponding compounds in this mixture. An analysis time of less than 18 min can be achieved using this column. Film thicknesses greater than 0.1 p.m cause longer retention times and a corresponding deterioration in peak shape (55). 

Modern gas chromatography is normally performed using fused silica capillary columns with a length of 15 to 30 m, an i.d. of 0.25 mm, and a film thickness of 0.25 pm. Columns of 50 m can also be used, but retention times are increased. 

The residue levels of 46 pesticides, including oxyfluorfen in soil, were determined using GC/ITDMS as described in S ection 3.2.1. The conditions for GC/ITDMS were as follows column, fused-silica capillary (30 m x 0.25-mm-i.d.) with a0.25- am bonded phase ofDB-5 column temperature, 50 °C (1 min), 30 °Cmin to 130 °C, 5 °C min to 270 °C inlet and transfer temperature, 270 and 220 °C, respectively He gas with column head pressure, 12psi injection method, splitless mode. The retention time and quantitation ion of oxyfluorfen were 23.9 min and mjz 252, respectively. ... 

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