{"id":43408,"date":"2020-10-06T00:00:00","date_gmt":"2020-10-06T00:00:00","guid":{"rendered":"https:\/\/discover.restek.com\/uncategorized\/optimisez-analyse-cov-polaires-co-elues-dans-echantillons-dair-total-preleves-dans-canisters-colonne-gc-rtx-vms\/"},"modified":"2026-01-29T14:27:43","modified_gmt":"2026-01-29T14:27:43","slug":"optimisez-analyse-cov-polaires-co-elues-dans-echantillons-dair-total-preleves-dans-canisters-colonne-gc-rtx-vms","status":"publish","type":"post","link":"https:\/\/discover.restek.com\/fr\/articles-fr\/evar2388-fr\/optimisez-analyse-cov-polaires-co-elues-dans-echantillons-dair-total-preleves-dans-canisters-colonne-gc-rtx-vms","title":{"rendered":"Optimisez l’analyse des COV polaires co-\u00e9lu\u00e9s dans \u00e9chantillons d\u2019air total pr\u00e9lev\u00e9s dans canisters colonne GC Rtx-VMS"},"content":{"rendered":"\n

Les laboratoires qui analysent les compos\u00e9s organiques volatils (COV) dans les \u00e9chantillons d\u2019air total pr\u00e9lev\u00e9s dans des canisters suivent la plupart du temps la m\u00e9thode TO-15 du recueil de l\u2019US EPA (Environmental Protection Agency) [1]. Souvent, les analystes qui utilisent cette m\u00e9thode se sentent \u00e0 tort oblig\u00e9s d\u2019utiliser une colonne de type 1 de 60 m x 0,32 mm x 1,00 \u03bcm. Or, il faut savoir que la m\u00e9thode TO-15 contient des recommandations et est bas\u00e9e sur les performances. Le choix des colonnes GC est donc tr\u00e8s souple concernant la phase stationnaire comme les dimensions des colonnes. Au sujet du choix des colonnes chromatographiques, la section 7.2.2.2 de la m\u00e9thode TO-15 indique : “Les colonnes capillaires en silice fondue 100% m\u00e9thyle silicone ou 5% ph\u00e9nyle et 95% m\u00e9thyle silicone de DI 0,25 \u00e0 0,53 mm et de longueur variable sont recommand\u00e9es pour la s\u00e9paration de nombreux sous-ensembles possibles de compos\u00e9s cibles contenant des compos\u00e9s apolaires. Toutefois, compte tenu de la diversit\u00e9 des compos\u00e9s-cibles, le choix est laiss\u00e9 \u00e0 l\u2019op\u00e9rateur dans la limite des normes de performance indiqu\u00e9es \u00e0 la section 11”.<\/p>\n\n\n\n

Cette flexibilit\u00e9 offre une opportunit\u00e9 d\u2019optimisation critique car la liste des analytes cibles varie entre les laboratoires. La M\u00e9thode TO-15 est applicable \u00e0 un sous-ensemble de 97 COVs parmi les 189 polluants atmosph\u00e9riques dangereux indiqu\u00e9s dans la loi f\u00e9d\u00e9rale des \u00c9tats-Unis sur la lutte contre la pollution atmosph\u00e9rique (Titre III des amendements du “Clean Air Act”). La plupart des laboratoires analysent une s\u00e9rie normalis\u00e9e d\u2019environ 65 COVs et certains chercheurs ajoutent une douzaine de compos\u00e9s suppl\u00e9mentaires mais seuls quelques laboratoires analysent les 97 compos\u00e9s. Comme la liste des compos\u00e9s cibles varie entre les laboratoires et puisque la m\u00e9thode permet l\u2019utilisation de toutes les colonnes r\u00e9pondant aux crit\u00e8res de performances obligatoires ci-apr\u00e8s, Restek a test\u00e9 plusieurs colonnes GC et \u00e9valu\u00e9 leur aptitude \u00e0 analyser des COVs dans les \u00e9chantillons d\u2019air total pr\u00e9lev\u00e9s dans des canisters. Les crit\u00e8res de la m\u00e9thode TO-15 sont les suivants : la teneur des COVs cibles dans les \u00e9chantillons t\u00e9moins ne doit pas d\u00e9passer les 0,2 ppbv ; les \u00e9talonnages soient r\u00e9alis\u00e9s avec un \u00e9cart-type relatif (%RSD) de 30% du facteur de r\u00e9ponse relatif (FRR) ; les limites de d\u00e9tection de la m\u00e9thode (LD) soient \u2264 0,5 ppbv ; la pr\u00e9cision de r\u00e9p\u00e9titions soit dans la limite de 25% ; et l\u2019exactitude des contr\u00f4les soit dans la limite de 30% pour les concentrations normalement attendues dans un air ambiant contamin\u00e9 (0,5 \u00e0 25 ppbv).<\/p>\n\n\n\n

Les premiers travaux ont montr\u00e9 qu\u2019un gain de temps significatif pouvait \u00eatre obtenu en utilisant une colonne de 30 m plut\u00f4t qu’une colonne de 60 m. Des temps d\u2019analyse GC inf\u00e9srieurs \u00e0 20 minutes ont \u00e9t\u00e9 atteints en respectant tous les crit\u00e8res de la m\u00e9thode avec une colonne MS Rxi-5Sil de 30 m x 0,32 mm x 1,00 \u03bcm [2]. Dans des travaux plus r\u00e9cents, Restek a r\u00e9ussi \u00e0 utiliser des phases de type 1, 5, 624 et VMS dans des colonnes de 30 m pour les 65 COVs couramment analys\u00e9s dans l\u2019air total\u00a0[3]. Toutes les phases ont bien fonctionn\u00e9, chacune des colonnes pr\u00e9sentant ses avantages et ses inconv\u00e9nients. Toutefois, la colonne Rtx-VMS (30 m x 0.32 mm x 1.80,\u00a0r\u00e9f. 19919) est ressortie globalement comme la meilleure colonne pour l\u2019analyse des COVs dans les \u00e9chantillons d\u2019air pr\u00e9lev\u00e9s dans des canisters, gr\u00e2ce \u00e0 ses excellentes performances chromatographiques pour les COVs polaires difficiles et \u00e0 son temps d\u2019analyse total court (Figure 1). Cette conclusion n\u2019est pas inattendue car la colonne Rtx-VMS est la seule colonne du march\u00e9 d\u00e9velopp\u00e9e sp\u00e9cifiquement pour l’analyse des compos\u00e9s volatils par spectrom\u00e9trie de masse (VMS = Volatile Mass Spec). La phase adapt\u00e9e et les dimensions de la colonne Rtx-VMS permettent de r\u00e9partir tous les COV cibl\u00e9s r\u00e9guli\u00e8rement le long du cycle GC, sans co-\u00e9lution critique (Figure 1). Il est important de noter que ces r\u00e9sultats ont \u00e9t\u00e9 obtenus avec un programme GC tr\u00e8s simple qui utilise des param\u00e8tres proches du d\u00e9bit optimal (SOF, speed optimized flow) et des vitesses de mont\u00e9e en temp\u00e9rature optimales (OHR, “Optimal Heating Rate”) jusqu\u2019\u00e0 150 \u00b0C\u00a0(voir l’article du blog Restek sur le SOF et l’OHR<\/a>). Les autres phases stationnaires peuvent atteindre ces performances mais avec des programmes GC plus cr\u00e9atifs et davantage de r\u00e9glages fins.<\/p>\n\n\n

Figure 1 :<\/strong>\u00a0D\u00e9velopp\u00e9e sp\u00e9cifiquement pour l\u2019analyse des compos\u00e9s volatils par MS, la colonne Restek Rtx-VMS offre la meilleure s\u00e9paration globale des COV dans les \u00e9chantillons d\u2019air total pr\u00e9lev\u00e9s dans des canisters, avec une analyse rapide de 13,5 minutes.<\/div>
\n
\"TO-15<\/div>

GC_AR1153<\/p>

Peaks<\/h4>\n
<\/th>Peaks<\/th>tR<\/sub> (min)<\/th><\/tr><\/thead>\n
1.<\/td>Propylene<\/a><\/td>1.42<\/td><\/tr>\n
2.<\/td>Dichlorodifluoromethane (CFC-12)<\/a><\/td>1.46<\/td><\/tr>\n
3.<\/td>1,2-Dichlorotetrafluoroethane (CFC-114)<\/a><\/td>1.60<\/td><\/tr>\n
4.<\/td>Chloromethane<\/a><\/td>1.63<\/td><\/tr>\n
5.<\/td>Vinyl chloride<\/a><\/td>1.72<\/td><\/tr>\n
6.<\/td>1,3-Butadiene<\/a><\/td>1.75<\/td><\/tr>\n
7.<\/td>Bromomethane<\/a><\/td>2.01<\/td><\/tr>\n
8.<\/td>Chloroethane<\/a><\/td>2.13<\/td><\/tr>\n
9.<\/td>Trichlorofluoromethane (CFC-11)<\/a><\/td>2.26<\/td><\/tr>\n
10.<\/td>1,1-Dichloroethene<\/a><\/td>2.67<\/td><\/tr>\n
11.<\/td>Carbon disulfide<\/a><\/td>2.68<\/td><\/tr>\n
12.<\/td>Ethanol<\/a><\/td>2.70<\/td><\/tr>\n
13.<\/td>1,1,2-Trichlorotrifluoroethane (CFC-113)<\/a><\/td>2.72<\/td><\/tr>\n
14.<\/td>Acrolein<\/a><\/td>2.96<\/td><\/tr>\n
15.<\/td>Isopropyl alcohol<\/a><\/td>3.14<\/td><\/tr>\n
16.<\/td>Methylene chloride<\/a><\/td>3.14<\/td><\/tr>\n
17.<\/td>Acetone<\/a><\/td>3.19<\/td><\/tr>\n
18.<\/td>trans-1,2-Dichloroethene<\/a><\/td>3.26<\/td><\/tr>\n
19.<\/td>Hexane<\/a><\/td>3.33<\/td><\/tr>\n
20.<\/td>Methyl tert-butyl ether (MTBE)<\/a><\/td>3.37<\/td><\/tr>\n
21.<\/td>Acetonitrile (contaminant)<\/a><\/td>3.57<\/td><\/tr>\n
22.<\/td>1,1-Dichloroethane<\/a><\/td>3.75<\/td><\/tr>\n
23.<\/td>Vinyl acetate<\/a><\/td>3.97<\/td><\/tr>\n<\/tbody><\/table>\n\n
<\/th>Peaks<\/th>tR<\/sub> (min)<\/th><\/tr><\/thead>
24.<\/td>cis-1,2-Dichloroethene<\/a><\/td>4.18<\/td><\/tr>\n
25.<\/td>Cyclohexane<\/a><\/td>4.33<\/td><\/tr>\n
26.<\/td>Bromochloromethane (IS)<\/a><\/td>4.34<\/td><\/tr>\n
27.<\/td>Chloroform<\/a><\/td>4.40<\/td><\/tr>\n
28.<\/td>Carbon tetrachloride<\/a><\/td>4.50<\/td><\/tr>\n
29.<\/td>Ethyl acetate<\/a><\/td>4.52<\/td><\/tr>\n
30.<\/td>Tetrahydrofuran<\/a><\/td>4.53<\/td><\/tr>\n
31.<\/td>1,1,1-Trichloroethane<\/a><\/td>4.56<\/td><\/tr>\n
32.<\/td>2-Butanone (MEK)<\/a><\/td>4.66<\/td><\/tr>\n
33.<\/td>Heptane<\/a><\/td>4.84<\/td><\/tr>\n
34.<\/td>Benzene<\/a><\/td>4.87<\/td><\/tr>\n
35.<\/td>1,2-Dichloroethane<\/a><\/td>5.04<\/td><\/tr>\n
36.<\/td>Trichloroethylene<\/a><\/td>5.36<\/td><\/tr>\n
37.<\/td>1,4-Difluorobenzene (IS)<\/a><\/td>5.40<\/td><\/tr>\n
38.<\/td>1,2-Dichloropropane<\/a><\/td>5.83<\/td><\/tr>\n
39.<\/td>Bromodichloromethane<\/a><\/td>5.89<\/td><\/tr>\n
40.<\/td>Methyl methacrylate<\/a><\/td>6.05<\/td><\/tr>\n
41.<\/td>1,4-Dioxane<\/a><\/td>6.11<\/td><\/tr>\n
42.<\/td>cis-1,3-Dichloropropene<\/a><\/td>6.48<\/td><\/tr>\n
43.<\/td>Toluene<\/a><\/td>6.70<\/td><\/tr>\n
44.<\/td>Tetrachloroethene<\/a><\/td>7.07<\/td><\/tr>\n
45.<\/td>4-Methyl-2-pentanone (MIBK)<\/a><\/td>7.10<\/td><\/tr>\n
46.<\/td>trans-1,3-Dichloropropene<\/a><\/td>7.13<\/td><\/tr>\n<\/tbody><\/table>\n\n
<\/th>Peaks<\/th>tR<\/sub> (min)<\/th><\/tr><\/thead>
47.<\/td>1,1,2-Trichloroethane<\/a><\/td>7.29<\/td><\/tr>\n
48.<\/td>Dibromochloromethane<\/a><\/td>7.46<\/td><\/tr>\n
49.<\/td>1,2-Dibromoethane<\/a><\/td>7.70<\/td><\/tr>\n
50.<\/td>2-Hexanone (MBK)<\/a><\/td>7.98<\/td><\/tr>\n
51.<\/td>Chlorobenzene-d5 (IS)<\/a><\/td>8.25<\/td><\/tr>\n
52.<\/td>Chlorobenzene<\/a><\/td>8.27<\/td><\/tr>\n
53.<\/td>Ethylbenzene<\/a><\/td>8.31<\/td><\/tr>\n
54.<\/td>m-Xylene<\/a><\/td>8.48<\/td><\/tr>\n
55.<\/td>p-Xylene<\/a><\/td>8.48<\/td><\/tr>\n
56.<\/td>o-Xylene<\/a><\/td>8.96<\/td><\/tr>\n
57.<\/td>Styrene<\/a><\/td>9.02<\/td><\/tr>\n
58.<\/td>Bromoform<\/a><\/td>9.03<\/td><\/tr>\n
59.<\/td>4-Bromofluorobenzene*<\/a><\/td>9.65<\/td><\/tr>\n
60.<\/td>1,1,2,2-Tetrachloroethane<\/a><\/td>9.92<\/td><\/tr>\n
61.<\/td>4-Ethyltoluene<\/a><\/td>9.96<\/td><\/tr>\n
62.<\/td>1,3,5-Trimethylbenzene<\/a><\/td>10.08<\/td><\/tr>\n
63.<\/td>1,2,4-Trimethylbenzene<\/a><\/td>10.55<\/td><\/tr>\n
64.<\/td>1,3-Dichlorobenzene<\/a><\/td>10.92<\/td><\/tr>\n
65.<\/td>1,4-Dichlorobenzene<\/a><\/td>11.04<\/td><\/tr>\n
66.<\/td>Benzyl chloride<\/a><\/td>11.37<\/td><\/tr>\n
67.<\/td>1,2-Dichlorobenzene<\/a><\/td>11.57<\/td><\/tr>\n
68.<\/td>Hexachlorobutadiene<\/a><\/td>13.14<\/td><\/tr>\n
69.<\/td>1,2,4-Trichlorobenzene<\/a><\/td>13.15<\/td><\/tr>\n
70.<\/td>Naphthalene<\/a><\/td>13.42<\/td><\/tr>\n<\/tbody><\/table>
*Tuning standard<\/div><\/div>

Conditions<\/h4>
Column<\/th>Rtx-VMS, 30 m, 0.32 mm ID, 1.80 \u00b5m (cat.# 19919<\/a>)<\/td><\/tr>
Standard\/Sample<\/th><\/td><\/tr>
<\/td>TO-15 65 component mix (cat.# 34436<\/a>)<\/td><\/tr>
<\/td>TO-14A internal standard\/tuning mix (cat.# 34408<\/a>)<\/td><\/tr>\n
Diluent:<\/th>Nitrogen<\/td><\/tr>
Conc.:<\/th>10.0 ppbv 200 cc injection<\/td><\/tr>
Injection<\/th>Direct<\/td><\/tr>
Oven<\/td><\/tr>
Oven Temp.:<\/th>32 °C (hold 1 min) to 150 °C at 11 °C\/min (hold 0 min) to 230 °C at 33 °C\/min (hold 0 min)<\/td><\/tr>
Carrier Gas<\/th>He, constant flow<\/td><\/tr>
Flow Rate:<\/th>2.0 mL\/min
Linear Velocity:<\/th>51 cm\/sec @ 32 \u00b0C<\/td><\/tr><\/table>
Detector<\/th>MS<\/td><\/tr>
Mode:<\/th>Scan<\/td><\/tr>
Scan Program:<\/th><\/td><\/tr>
Group<\/th>Start Time
(min)<\/th>		Scan Range
(amu)<\/th>		Scan Rate
(scans\/sec)<\/th><\/tr><\/thead>
1<\/td>0<\/td>35-250<\/td>3.32<\/td><\/tr><\/tbody><\/table><\/td><\/tr>
Transfer Line Temp.:<\/th>230 \u00b0C<\/td><\/tr>
Analyzer Type:<\/th>Quadrupole <\/td><\/tr>
Source Temp.:<\/th>230 \u00b0C<\/td><\/tr>
Quad Temp.:<\/th>150 \u00b0C<\/td><\/tr>
Electron Energy:<\/th>69.9 eV<\/td><\/tr>
Solvent Delay Time:<\/th>1.0 min<\/td><\/tr>
Tune Type:<\/th>BFB <\/td><\/tr>
Ionization Mode:<\/th>EI <\/td><\/tr>
Preconcentrator<\/th>Nutech 8900DS<\/td><\/tr>
  Trap 1 Settings<\/th><\/td><\/tr>
  Type\/Sorbent :<\/th>Glass beads <\/td><\/tr>
  Cooling temp:<\/th>-155 \u00b0C<\/td><\/tr>
  Preheat temp:<\/th>5 \u00b0C<\/td><\/tr>
  Preheat time:<\/th>0 sec<\/td><\/tr>
  Desorb temp:<\/th>20 \u00b0C<\/td><\/tr>
  Desorb flow:<\/th>5 mL\/min<\/td><\/tr>
  Desorb time:<\/th>360 sec<\/td><\/tr>
  Bakeout temp:<\/th>200 \u00b0C<\/td><\/tr>
  Flush flow:<\/th>120 mL\/min<\/td><\/tr>
  Flush time:<\/th>60 sec<\/td><\/tr>
  Sweep flow:<\/th>120 mL\/min<\/td><\/tr>
  Sweep time:<\/th>60 sec<\/td><\/tr>
  Trap 2 Settings<\/th><\/td><\/tr>
  Type\/Sorbent:<\/th>Tenax <\/td><\/tr>
  Cooling temp:<\/th>-35 \u00b0C<\/td><\/tr>
  Desorb temp:<\/th>190 \u00b0C<\/td><\/tr>
  Desorb time:<\/th>30 sec<\/td><\/tr>
  Bakeout temp:<\/th>200 \u00b0C<\/td><\/tr>
  Bakeout time:<\/th>10 sec<\/td><\/tr>
  Cryofocuser<\/th><\/td><\/tr>
  Cooling temp:<\/th>-160 \u00b0C<\/td><\/tr>
  Inject time:<\/th>140 sec<\/td><\/tr>
  Internal Standard<\/th><\/td><\/tr>
  Purge flow:<\/th>100 mL\/min<\/td><\/tr>
  Purge time:<\/th>6 sec<\/td><\/tr>
  Vol.:<\/th>20 mL<\/td><\/tr>
  ISTD flow:<\/th>100 mL\/min<\/td><\/tr>
  Standard<\/th><\/td><\/tr>
  Size:<\/th>200 mL<\/td><\/tr>
  Purge flow:<\/th>100 mL\/min<\/td><\/tr>
  Purge time:<\/th>6 sec<\/td><\/tr>
  Sample flow:<\/th>100 mL\/min<\/td><\/tr>
Instrument<\/th>HP6890 GC & 5973 MSD<\/td><\/tr>
Acknowledgement<\/th>Nutech<\/td><\/tr><\/table><\/div><\/div><\/div>
<\/path><\/g><\/path><\/g><\/svg>Download PDF<\/a><\/div><\/div><\/div>\n<\/div><\/div><\/div>\n\n\n

De plus, comme le montre la Figure 2, L\u2019analyse des COVs polaires dans les \u00e9chantillons d\u2019air total (en particulier l\u2019\u00e9thanol et l\u2019alcool isopropylique) par une colonne Rtx-VMS de polarit\u00e9 interm\u00e9diaire et de s\u00e9lectivit\u00e9 unique permet d\u2019obtenir des pics bien plus fins (aucune tra\u00een\u00e9e de pic) qu\u2019avec les autres types de phases. La grande finesse des pics rend l\u2019int\u00e9gration plus facile et plus fiable, ce qui contribue \u00e0 am\u00e9liorer l\u2019exactitude et la pr\u00e9cision.<\/p>\n\n\n

Figure 2 :<\/strong>\u00a0Des r\u00e9sultats plus pr\u00e9cis pour l\u2019analyse des COV dans l\u2019air total pr\u00e9lev\u00e9 dans des canisters (par exemple, l\u2019\u00e9thanol) gr\u00e2ce aux pics sym\u00e9triques g\u00e9n\u00e9r\u00e9s avec la colonne Rtx-VMS.<\/div>
\n
\"Ethanol<\/div>

GC_AR1164<\/p>

Peaks<\/h4>\n
<\/th>Peaks<\/th>tR<\/sub> (min)<\/th>Ion 1<\/th>Ion 2 <\/th>Ion 3<\/th><\/tr><\/thead>\n
1.<\/td>Ethanol<\/a><\/td>2.689<\/td>45.0<\/td>46.0<\/td>43.0<\/td><\/tr>\n<\/tbody><\/table><\/div>

Conditions<\/h4>
Column<\/th>Rtx-VMS, 30 m, 0.25 mm ID, 1.40 \u00b5m (cat.# 19915<\/a>)<\/td><\/tr>
Standard\/Sample<\/th><\/td><\/tr>
<\/td>75 Comp TO15 + NJ mix (cat.# 34396<\/a>)<\/td><\/tr>
<\/td>TO-14A internal standard\/tuning mix (cat.# 34408<\/a>)<\/td><\/tr>\n
Diluent:<\/th>Nitrogen<\/td><\/tr>
Conc.:<\/th>10.0 ppbv 250 mL injection<\/td><\/tr>
Injection<\/th>Direct<\/td><\/tr>
Oven<\/td><\/tr>
Oven Temp.:<\/th>32.0 °C (hold 5 min) to 150 °C at 8 °C\/min to 230 °C at 33 °C\/min<\/td><\/tr>
Carrier Gas<\/th>He, constant flow<\/td><\/tr>
Flow Rate:<\/th>2.0 mL\/min
Linear Velocity:<\/th>51 cm\/sec @ 32 \u00b0C<\/td><\/tr><\/table>
Detector<\/th>MS<\/td><\/tr>
Mode:<\/th>Scan<\/td><\/tr>
Scan Program:<\/th><\/td><\/tr>
Group<\/th>Start Time
(min)<\/th>		Scan Range
(amu)<\/th>		Scan Rate
(scans\/sec)<\/th><\/tr><\/thead>
1<\/td>0<\/td>35-250<\/td>3.32<\/td><\/tr><\/tbody><\/table><\/td><\/tr>
Transfer Line Temp.:<\/th>230 \u00b0C<\/td><\/tr>
Analyzer Type:<\/th>Quadrupole <\/td><\/tr>
Source Type:<\/th>Extractor <\/td><\/tr>
Extractor Lens:<\/th>6 mm ID<\/td><\/tr>
Source Temp.:<\/th>230 \u00b0C<\/td><\/tr>
Quad Temp.:<\/th>150 \u00b0C<\/td><\/tr>
Electron Energy:<\/th>70 eV<\/td><\/tr>
Tune Type:<\/th>BFB <\/td><\/tr>
Ionization Mode:<\/th>EI <\/td><\/tr>
Preconcentrator<\/th>Markes CIA Advantage<\/td><\/tr>
Instrument<\/th>Agilent 7890B GC & 5977A MSD<\/td><\/tr>
Acknowledgement<\/th>Markes International<\/td><\/tr><\/table><\/div><\/div><\/div>
<\/path><\/g><\/path><\/g><\/svg>Download PDF<\/a><\/div><\/div><\/div>\n<\/div><\/div><\/div>\n\n\n

Enfin, la spectrom\u00e9trie de masse permet de d\u00e9terminer un grand nombre de COVs co-\u00e9lu\u00e9s dans les \u00e9chantillons d\u2019air total pr\u00e9lev\u00e9s dans des canisters mais les compos\u00e9s qui partagent certains ions (comme le butane et le 1,3-butadi\u00e8ne) ne sont pas quantifi\u00e9s avec pr\u00e9cision par spectrom\u00e9trie de masse \u00e0 moins de les avoir s\u00e9par\u00e9s par chromatographie. Le butane et le 1,3-butadi\u00e8ne ne co-\u00e9luent pas sur la colonne Rtx-VMS mais c\u2019est souvent le cas avec d\u2019autres phases, ce qui peut conduire les laboratoires \u00e0 rapporter des concentrations artificiellement \u00e9lev\u00e9es. Comme aucune co-\u00e9lution critique n\u2019a \u00e9t\u00e9 observ\u00e9e avec la colonne Rtx-VMS pour les 65 COV \u00e9valu\u00e9s, la colonne Rtx-VMS est fortement recommand\u00e9e lorsque la s\u00e9paration chromatographique est essentielle.<\/p>\n\n\n

Figure 3 :<\/strong>\u00a0La colonne Rtx-VMS permet d\u2019obtenir des r\u00e9sultats plus pr\u00e9cis car elle s\u00e9pare par chromatographie les COV co\u00e9lu\u00e9s impossibles \u00e0 d\u00e9terminer seulement avec la MS.<\/div>
\n
\"Butane<\/div>

GC_AR1163<\/p>

Peaks<\/h4>\n
<\/th>Peaks<\/th>tR<\/sub> (min)<\/th>Ion 1<\/th>Ion 2 <\/th>Ion 3<\/th><\/tr><\/thead>\n
1.<\/td>n-Butane<\/a><\/td>1.461<\/td>43.0<\/td>41.0<\/td>39.0<\/td><\/tr>\n
2.<\/td>1,3-Butadiene<\/a><\/td>1.521<\/td>39.0<\/td>54.0<\/td>53.0<\/td><\/tr>\n<\/tbody><\/table><\/div>

Conditions<\/h4>
Column<\/th>Rtx-VMS, 30 m, 0.25 mm ID, 1.40 \u00b5m (cat.# 19915<\/a>)<\/td><\/tr>
Standard\/Sample<\/th><\/td><\/tr>
<\/td>75 Comp TO15 + NJ mix (cat.# 34396<\/a>)<\/td><\/tr>
<\/td>TO-14A internal standard\/tuning mix (cat.# 34408<\/a>)<\/td><\/tr>\n
Diluent:<\/th>Nitrogen<\/td><\/tr>
Conc.:<\/th>10.0 ppbv 250 mL injection<\/td><\/tr>
Injection<\/th>Direct<\/td><\/tr>
Oven<\/td><\/tr>
Oven Temp.:<\/th>32.0 °C (hold 5 min) to 150 °C at 8 °C\/min to 230 °C at 33 °C\/min<\/td><\/tr>
Carrier Gas<\/th>He, constant flow<\/td><\/tr>
Flow Rate:<\/th>2.0 mL\/min
Linear Velocity:<\/th>51 cm\/sec @ 32 \u00b0C<\/td><\/tr><\/table>
Detector<\/th>MS<\/td><\/tr>
Mode:<\/th>Scan<\/td><\/tr>
Scan Program:<\/th><\/td><\/tr>
Group<\/th>Start Time
(min)<\/th>		Scan Range
(amu)<\/th>		Scan Rate
(scans\/sec)<\/th><\/tr><\/thead>
1<\/td>0<\/td>35-250<\/td>3.32<\/td><\/tr><\/tbody><\/table><\/td><\/tr>
Transfer Line Temp.:<\/th>230 \u00b0C<\/td><\/tr>
Analyzer Type:<\/th>Quadrupole <\/td><\/tr>
Source Type:<\/th>Extractor <\/td><\/tr>
Extractor Lens:<\/th>6 mm ID<\/td><\/tr>
Source Temp.:<\/th>230 \u00b0C<\/td><\/tr>
Quad Temp.:<\/th>150 \u00b0C<\/td><\/tr>
Electron Energy:<\/th>70 eV<\/td><\/tr>
Tune Type:<\/th>BFB <\/td><\/tr>
Ionization Mode:<\/th>EI <\/td><\/tr>
Preconcentrator<\/th>Markes CIA Advantage<\/td><\/tr>
Instrument<\/th>Agilent 7890B GC & 5977A MSD<\/td><\/tr>
Acknowledgement<\/th>Markes International<\/td><\/tr><\/table><\/div><\/div><\/div>
<\/path><\/g><\/path><\/g><\/svg>Download PDF<\/a><\/div><\/div><\/div>\n<\/div><\/div><\/div>\n\n\n

En conclusion, les laboratoires analysants les COV dans les \u00e9chantillons d\u2019air total pr\u00e9lev\u00e9s dans des canisters selon la m\u00e9thode TO-15 devraient savoir que cette m\u00e9thode est fond\u00e9e sur les performances. Elle est suffisamment souple pour leur permettre de r\u00e9duire les temps d\u2019analyse en passant d’une colonne de 60 m \u00e0 une colonne de 30 m. Une grande vari\u00e9t\u00e9 de colonnes de 30 m permet d\u2019obtenir d\u2019excellents r\u00e9sultats (y compris les colonnes MS Rxi-1ms, Rxi-5ms, Rxi-5Sil MS et Rxi-624Sil) mais la colonne Rtx-VMS offre les meilleures performances globales et elle est particuli\u00e8rement recommand\u00e9e lorsque des COVs polaires ou co-\u00e9lu\u00e9s figurent dans les analytes cibles. Les pics tr\u00e8s sym\u00e9triques et l\u2019absence de co-\u00e9lutions critiques am\u00e9liorent les \u00e9talonnages, les limites de d\u00e9tection de la m\u00e9thode et la r\u00e9p\u00e9tabilit\u00e9.<\/p>\n\n\n\n

<\/div>\n\n\n\n

R\u00e9f\u00e9rences<\/h2>\n\n\n\n
    \n
  1. U.S. Environmental Protection Agency, Compendium Method TO-15, Determination of volatile organic compounds [VOCs] in air collected in specially-prepared canisters and analyzed by gas chromatography\/mass spectrometry (GC\/MS), January 1999. http:\/\/www3.epa.gov\/ttnamti1\/files\/ambient\/airtox\/to-15r.pdf<\/a><\/li>\n\n\n\n
  2. J.S. Herrington, Rapid determination of TO-15 volatile organic compounds (VOCs) in air<\/a>, Application note, EVAN1725A-UNV, Restek Corporation, 2014.<\/li>\n\n\n\n
  3. J.S. Herrington,\u00a0Air columns \u2013 part II: You only need a 30 m column for EPA Method TO-15!, ChromaBLOGraphy, Restek Corporation, 2013.<\/li>\n\n\n\n
  4. J. Cochran, Speed optimized flow and optimal heating rate in gas chromatography<\/a>, ChromaBLOGraphy, Restek Corporation, 2010.<\/li>\n<\/ol>\n\n\n\n
    <\/div>\n\n\n
    \n

    Products Mentioned<\/h3>\n
    \n
    \n
    \n
    \n Catalog No. 19919 <\/a> <\/div>\n
    \n
    Colonne capillaire Rtx-VMS, L 30 m, DI 0.32 mm, 1.80 \u00b5m<\/div>\n <\/div>\n
    \n Voir le produit<\/a>\n <\/div>\n <\/div>\n <\/div>\n <\/div>\n \n\n\n
    <\/div>\n","protected":false},"excerpt":{"rendered":"

    \u00c9tant donn\u00e9 que la m\u00e9thode TO-15 est une m\u00e9thode bas\u00e9e sur les performances pour l’analyse des COV dans des \u00e9chantillons d’air total pr\u00e9lev\u00e9s dans des canisters, les laboratoires ont la possibilit\u00e9 d’utiliser n’importe quelle colonne GC qui r\u00e9pond aux crit\u00e8res de performances obligatoires. Des colonnes plus courtes peuvent \u00eatre utilis\u00e9es pour r\u00e9duire les temps d’analyse et des phases stationnaires qui s\u00e9parent les co\u00e9lutions difficiles peuvent \u00eatre s\u00e9lectionn\u00e9es. Apr\u00e8s \u00e9valuation d’une grande vari\u00e9t\u00e9 de colonnes, la colonne Rtx-VMS offre la meilleure performance globale et est particuli\u00e8rement recommand\u00e9e lorsque des compos\u00e9s polaires ou co\u00e9lutifs sont inclus dans la liste des analytes cibles.<\/p>\n","protected":false},"author":25,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kadence_starter_templates_imported_post":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"footnotes":""},"categories":[462],"tags":[],"industries-application":[2209,2208],"post-badge":[],"resource-type":[],"product-library":[2449,2456,2443,2446,2452,2444],"resource-technique":[2316,2315,2320],"hf_cat_post":[650],"ppma_author":[445],"class_list":["post-43408","post","type-post","status-publish","format-standard","hentry","category-articles-fr","industries-application-analyses-de-lair","industries-application-environnement","product-library-canisters-accessoires","product-library-colonnes-gc","product-library-echantillonnage-dair-et-de-gaz","product-library-etalons-de-reference","product-library-etalons-gazeux-accessoires","product-library-produits-pour-la-chromatographie-en-phase-gazeuse","resource-technique-chromatographie-en-phase-gazeuse-gc","resource-technique-echantillonnage-dair","resource-technique-spectrometrie-de-masse-ms"],"acf":[],"taxonomy_info":{"category":[{"value":462,"label":"Articles"}],"industries-application":[{"value":2209,"label":"Analyses de l'air"},{"value":2208,"label":"Environnement"}],"product-library":[{"value":2449,"label":"Canisters et accessoires"},{"value":2456,"label":"Colonnes GC"},{"value":2443,"label":"\u00c9chantillonnage d'air et de gaz"},{"value":2446,"label":"\u00c9talons de R\u00e9f\u00e9rence"},{"value":2452,"label":"\u00c9talons gazeux et accessoires"},{"value":2444,"label":"Produits pour la chromatographie en phase gazeuse"}],"resource-technique":[{"value":2316,"label":"Chromatographie en phase gazeuse (GC)"},{"value":2315,"label":"\u00c9chantillonnage d'air"},{"value":2320,"label":"Spectrom\u00e9trie de masse (MS)"}]},"featured_image_src_large":false,"author_info":{"display_name":"Jason S. 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