2017 5 26 350 Restek
time time time increasing time
μ
= = k = t r t o t o = t r ' t o
van Deemter Equation H A B H = height equivalent theoretical plate (HETP) A = Eddy diffusion term B = Molecular diffusion in column axis division (contributes to band broadening) C = Resistance to mass transfer (contributes to band broadening) C H (mm) 1.0 0.6 0.2 R = 1 4 N 2 He H 2 (cm/s) optimum 10cm/s N optimum = 20cm/s 40cm/s HeH 2 2 L H k X X k+1-1
(R) (t R ) R t R t R R t R
Dimethyl CH 3 Si O Phenylmethyl Si CH 3 O Diphenyl Si O Trifluoropropyl methyl CF 3 C 2 H 4 Si CH 3 O Cyanopropyl Phenyl C N (CH 2 ) 3 Si O H C H Polyethylene glycol (PEG) H C H O Biscyanopropyl C N (CH 2 ) 3 Si O (CH 2 ) 3 C N CH 3
CH 3 Si O CH 3 Si O Si CH 3 O C N (CH 2 ) 3 Si O CF 3 C 2 H 4 Si O CH 3 Rxi-1ms/Rtx -1 100% Rxi-5ms/Rtx -5 Rtx -20 Rtx -35 / Rtx -35MS Rtx -17 95% 80% 65% 50% 5% 20% 35% 50% Rtx -50 100% Rtx -65 35% 65% Rtx -200 100% Rtx -624 or 1301 94% 6% Rtx -1701 86% 14% 11
(%) (Rtx 5 vs. Rtx 35) Likes dissolve likes( )
0.25µm Rtx -1 30m, 0.32mm ID, 0.25µm 1 6 7 8 9 min 2 4 6 McReynolds probes 1. 1 butanol 2. benzene 3. 2 pentanone 4. C 7 5. 1 nitropropane 6. pyridine 7. C 8 8. C 9 9. C 10 5.5 min 70 o C isothermal
min 30m, 0.32mm ID, 1.0µm 7 1 6 8 4 8 12 1.0µm Rtx -1 McReynolds probes 1. 1 butanol 2. benzene 3. 2 pentanone 4. C 7 9 5. 1 nitropropane 6. pyridine 7. C 8 8. C 9 9. C 10 18 min. 16 20 70 o C isothermal
3.0µm Rtx -1 4 30m, 0.32mm ID, 3.0µm min 1,2,3 5 6 All are baseline resolved 7 4 8 12 8 16 20 24 McReynolds probes 1. 1 butanol 2. benzene 3. 2 pentanone 4. C 7 5. 1 nitropropane 6. pyridine 7. C 8 8. C 9 9. C 10 68 min. 70 o C isothermal
4 30m, 0.32mm ID, 5.0µm 1,2,3 5 6 5.0µm Rtx -1 7 McReynolds probes 1. 1 butanol 2. benzene 3. 2 pentanone 4. C 7 5. 1 nitropropane 70 o C isothermal 8 6. pyridine 7. C 8 8. C 9 9. C 10 117 min. 9 min 4 8 12 16 20 24 28 32 36 40 120
Rtx 1: 30m, 0.53mm ID, 0.25mm Rtx 1: 30m, 0.53mm ID, 5.0mm The supplier reported the purity as 99% using this column. Pentane 40 o C isothermal A closer look on a thick film column revealed that it was not. 1mL direct injection
0.10mm ID 0.18mm ID 0.25mm ID 0.28mm ID 0.32mm ID 0.45mm ID 0.53mm ID GC/MS 0.1mm ID fast GC &
( EPA 604 Phenols min. 4 8 12 16 20 24 min. 4 8 12 16 20 Rtx 5: 30m, 0.25mm ID, 0.25mm Rtx 5: 30m, 0.53mm ID, 0.25mm
21
30.7m x 0.25mm x 0.25µm Rxi-5ms 1.4 ml/min; 8.5 C/min 15.45min 2.0 ml/min; 10.1 C/min 13.00min 4.0 ml/min; 14.3 C/min 9.23min
High Bleed 25
High Bleed 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 24.00 26.00 28.00
High Bleed 1ng 8270 compounds small leak leaking press tight front excessive MeCl2 207 600000 550000 500000 44 73 281 450000 400000 97 133 355 252 176.9 350000 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 300000 250000 200000 150000 100000 50000 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 24.00 26.00 28.00
High Bleed 6000000 5500000 5000000 4500000 4000000 3500000 3000000 2500000 2000000 1500000 1000000 500000 4.00 6.00 8.00 10.00 12.00 14.00 16.00
Bleed fixed 1.3e+07 1.2e+07 1.1e+07 1e+07 9000000 8000000 7000000 6000000 5000000 4000000 3000000 2000000 1000000 4.00 6.00 8.00 10.00 12.00 14.00 16.00
PEG vs. PDMS 207.0 Spectral Background Rtx 5Sil MS 30mx0.25mmx 1.0df ser#486245 43.1 73.0 132.9 281.0 102.9 176.9 250.9 310.9 355.0 372.6 414.9 450.1 44.1 89.0 Spectral Background Stabilwax 30mx0.25mmx0.25df ser#672605 67.0 110.0 133.0 157.1 180.9 206.9 232.7 253.9 275.1 302.3 http://www.restek.com/blog/?post=44_i-want-answers-peg-aka-wax-phases-for-my-gcms-----seriously-why-not
2200000 2000000 1800000 1600000 1400000 1200000 1000000 800000 600000 400000 200000 0 TIC: C0226228.D 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 2400000 2200000 2000000 1800000 1600000 1400000 1200000 1000000 800000 600000 400000 200000 4.00 0 TIC: C0226227.D Bis(2 ethylhexyl)phthalate m/z 149, 167, 279 Triphenylphosphine Oxide m/z 277 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 http://www.restek.com/blog/?post=84_unraveling-the-mysteries-of-ghost-peaks-it146s-time-to-pull-the-sheet-off PAH Carryover m/z 278
1 Figure: Stabilwax column isothermal at 35 C. 5 C below the solid liquid phase transition temperature. Notice the differences in retention for the three overlaid chromatograms. 2 3 4 Peaks 1 Air 2 chloromethane 3 vinyl chloride 4 ethylene oxide 2.20 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 4.20 4.40 4.60 4.80 http://www.restek.com/blog/?post=70_volatiles--peg-phases-look-out-for-that-spooky-glass-transition-temperature-
Pyridine m/z 79 2.24 @ 10ng 2.26 @ 2.5ng 2.32 @ 1.0ng Fluorophenol m/z 112 3.24 2.20 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 Fails 8270D Revision 4 Criteria for RRT 0.06 min
2.46 @ 10ng 3.25 Pyridine m/z 79 2.45 @ 1.0ng Fluorophenol m/z 112 2.48 @ 0.5ng 2.20 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80
Rtx-Volatile Amine 1.Pyridine 2.1,2 Butanediol 3.Nonane 4.Diethylenetriamine 5.Diethanolamine 6.2 Nonanol 7.2,6 Dimethylamine 8.Dodecane Column: Rtx Volatile Amine, 60 m, 0.32 mm ID (cat.# 18078) Sample: Volatile amine column test mix (cat.# 35008) Diluent: Methanol:dichloromethane (50:50) Conc.: 900 1,800 µg/ml snap and shoot Inj. Vol.: 1 µl split (split ratio 17.8:1)
44 57 83 97 70 111 129 149 185 171 207 m/z--> 380000 360000 340000 320000 300000 280000 260000 240000 220000 200000 180000 160000 140000 120000 100000 80000 60000 40000 TIC: GR3028E8.D 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 24.00 26.00 28.00
8.00 10.00 12.00 14.00 16.00 8.00 10.00 12.00 14.00 16.00
* * * * Dichlobenil Dichlobenil in Acetonitrile Peak Splitting Oven Temperature Start 40 C
1 Naphthol Dichlobenil THPI OPP Pebulate Mevinphos