GC-MS Analysis of Polychlorinated Biphenyl Congeners Using ... · PDF fileGC-MS Analysis of...

GC-MS Analysis of Polychlorinated Biphenyl Congeners Using a New

Capillary GC ColumnFrank L. Dorman, Gary B. Stidsen, Chris M.

English and Lydia NolanRestek Corporation, Bellefonte, PA

Jack CochranLECO Corporation, Las Vegas, NV

Abstract• The analysis of polychlorinated biphenyls (PCB’s) by GC can be a

very challenging analysis. Numerous researchers have demonstrated various separations on the common commercially available GC stationary phases, but all of these have had limitations when it comes to the separation of all 209 possible PCB congeners. While it may be argued that the complete separation of all 209 possible congeners is not necessary, separation of the environmentally significant and the toxic congeners is important.

• The separation requirements for the analysis of PCB congeners differ considerably depending on the type of detector used. Separation needs when using a mass spectrometer are different then when using standard GC detectors.

• This presentation will discuss the separation needs for PCB congeners when using a mass spectrometer, and demonstrate an improved separation of PCB congeners, using a new capillary stationary phase developed for this purpose.

Experiment• Determine retention times for all 209 PCBs on

a new low-bleed capillary column – AccuStandard 9 mixtures– Hexachlorobenzene for relative retention times

• Analyze mix of Aroclors 1221:1242:1254:1262– 1:2:2:2 ratio– Show chromatogram with congeners labeled

• GC-MS results obtained using a time-of-flight mass spectrometer to allow for possible spectral deconvolution

GC-TOFMS Conditions• Gas Chromatography

– One microliter splitless 250°C, 60 sec valve – 60 m x 0.18 mm x 0.18 µm Restek Rtx-PCB column

• Constant flow helium, 1.5 mL/minute• 70°C (1 min), 50°/min to 120°, 3°/min to 360° (1 min)

• Mass Spectrometry LECO Pegasus III– Source temperature: 225°C– Electron ionization: 70 eV– Stored mass range: 120 to 520 u– Acquisition rate: 5 spectra/sec

Aroclor Mix Chromatogram• Overlaid ion chromatograms are plotted

– For example, hexachlorobiphenyl is 360– Peaks are labeled with congener numbers

• Text size and format is only for space and not meant to indicate anything about PCBs, except:

• European indicator congeners are in red

• Chromatograms are not to one scale– Each panel is adjusted so most of the PCB

peaks can be seen

1

2

3

4+10

9 7

6

5

8

19

18

17

12 27

13

24

16 32

15

3423

54 29

26

25

31 28

33

51

45

22

46 43

52

48

49

53 20

47

75

44

59

4271

35

417296

103

64

40

37

67 102

95

74

70

94 57 98

639376

91

66

55

92

89+84

101

99

60

11983

12586

97

87

154

110

85

115

136117

56

151

135 82

144

147+149

77139

124123+109

134133

118153

114

122

146

131

132 179

141

176

105

137

130164

138

163

129

158

187

175

183

166

185

174

128

202167

177

201171

172173 197

178

156157

180

193 200

191 198

199

170

196

203

190

208

207 189

195

194

205

206

Important Congener Separations

• European indicator PCBs

• May coelute on 5% phenyl methylsiliconeand other column phases

31 28

33Trichlorobiphenyls

20

153

132

Hexachlorobiphenyls

138

163

Hexachlorobiphenyls

Table Key• Congener classification according to their significance in

Aroclors 1242, 1254, or 1260– Bold Underline: Congener > 1.0 Wt%

– Bold: Congener 0.05 to 1.0 Wt%

– Italics: Trace or undetected congener

• Congener naming according to Guitart et al. by chlorine positions– 107: 234-35– 108: 2346-3– 109: 235-34

– 199: 2345-2356– 200: 23456-236– 201: 2346-2356

• RRT is relative retention time

• Coelutions of significance where MS won’t help are

2110.92109.32093.32088.12067.32061.12053.31993.51963.31953.31894.31882.31849.31815.31808.31679.71678.11642.11601.31403.3

RT (sec)

1.083935.183241.082935.152131.074834.893271.072134.802121.061534.463171.058234.352111.054334.223181.023633.223301.007932.722141.003032.553190.972731.57280.966531.37250.949630.82260.932130.26270.928530.14290.862528.002100.861727.97240.843227.37130.822226.69120.720623.3911RRTRT (min)Cl#PCB#

2374.32364.32349.52313.32312.72312.92309.52303.52290.72286.52252.72239.32237.12202.72188.92187.32176.12158.92148.72135.1

RT (sec)

1.218939.574731.214039.403221.206439.164451.187738.563201.187438.543211.187438.554511.185838.493331.182838.393281.176238.183311.173838.114531.156737.543251.149837.323261.148637.284501.130936.713291.123736.484541.123436.453231.117336.273341.108435.982151.103335.813321.096335.58316RRTRT (min)Cl#PCB#

2535.72527.92521.52506.72501.32487.32461.32452.92450.72451.32448.52444.72440.32426.52417.32406.92398.92397.72391.52374.5

RT (sec)

1.302042.264411.297842.133351.294742.024711.287041.784421.284241.694591.277241.454441.263741.023381.259840.883391.258640.844621.258440.854751.257140.814651.255240.754471.252940.6751041.245840.444491.241240.294481.235940.114521.231739.983361.231239.964431.227939.864691.219339.58446RRTRT (min)Cl#PCB#

2657.52653.92650.92646.12646.12637.92635.92618.92614.72613.52594.12589.12581.92581.32569.92561.92560.52552.32545.12542.1

RT (sec)

1.364644.295951.363044.2351211.361044.184631.358744.104761.358644.105931.354443.965981.353343.934611.344643.6551021.342643.584581.342043.564671.331943.234571.329743.155941.325543.0351001.325443.023371.319542.834401.315342.704641.315042.674681.310542.5451031.306742.425961.305242.37472RRTRT (min)Cl#PCB#

2802.32798.92776.72776.12772.92757.32751.52751.52750.92745.92743.72726.52723.32709.72695.72688.72678.32675.72667.92658.9

RT (sec)

1.438846.7151191.437046.6561521.425846.284601.425846.2751501.423846.215991.415745.9551131.412845.864561.412545.865901.412445.8551011.410045.775841.408745.735891.399945.445921.398445.394551.391745.164801.384244.934661.380544.815911.375244.644701.374244.5961551.369944.464741.365644.31588RRTRT (min)Cl#PCB#

2906.72895.72889.12883.52878.92877.32871.12870.32868.32867.72855.52841.92835.52828.92825.92821.52817.72812.12811.32807.5

RT (sec)

1.492548.4451101.486948.2651201.483348.155851.480648.0651151.478047.9851171.477347.9661361.474647.8551111.473747.844781.472847.805871.472247.7961541.466547.5951161.459147.364791.456347.2661481.452447.155971.450947.1061451.448847.0251081.446746.965861.444046.8751121.443846.8551251.441646.79583RRTRT (min)Cl#PCB#

3027.53023.13018.93018.53011.53011.33009.53005.32990.52988.92981.32980.32972.32968.32966.32949.12948.32937.32929.12927.7

RT (sec)

1.554950.4661421.552150.3861331.550050.3151061.549850.3161341.546750.1971881.546250.1951091.545250.1651231.543050.0951071.535949.8461431.534449.8151241.530749.6961391.530649.6761401.526149.544771.524149.4761491.523149.4461471.514249.1561441.513949.145821.508248.9661351.503948.8261511.503048.79481RRTRT (min)Cl#PCB#

3171.13168.73157.73157.13150.73140.93137.53125.73109.33094.13077.13076.13072.53060.33060.13050.33044.13040.73034.33032.5

RT (sec)

1.628352.8561641.626752.8161301.621252.6351271.621152.6271861.617752.5161371.612652.3551051.610952.2971761.605052.1061411.596651.8271791.588751.5761321.580051.2861531.579451.2751141.578051.2161681.571251.0061611.571051.0051221.566350.8461461.562850.7361651.561250.6871841.558050.5761311.557050.545118RRTRT (min)Cl#PCB#

3328.93322.73321.13307.73307.93295.93293.33290.33277.33264.13243.33221.13210.53209.73208.53203.93198.93196.73191.73187.7

RT (sec)

1.709155.4871811.706055.3861671.705055.3582021.698455.1371741.698455.1361281.692754.9361621.690954.8971851.689354.8451261.682854.6261591.675954.4061661.665454.0671831.654053.6871871.648253.5171751.648053.4971821.647353.4861581.645053.4061291.642953.3161601.641153.2861631.638953.1961381.636853.137178RRTRT (min)Cl#PCB#

3569.33564.73564.73546.93539.93534.33456.53447.73437.53432.13430.13415.33414.73403.13383.13379.73366.13353.93352.33348.5

RT (sec)

1.832859.4982031.830459.4181961.830259.4171901.821259.1271701.817759.0081991.814858.9081981.774757.6171911.770057.4682001.765157.2971931.762357.2071801.761157.1761571.753556.9261561.753456.9171921.747456.7271721.737156.3981971.735456.3371731.728456.1071711.722055.9082041.721055.8782011.719455.817177RRTRT (min)Cl#PCB#

3952.93872.33791.53766.93692.93683.33676.53643.73583.5

RT (sec)

2.029565.88102091.988464.5492061.946863.1982051.934262.7881941.896261.5581951.891161.3971891.887661.2892071.870860.7392081.839959.726169RRTRT (min)Cl#PCB#

Conclusions• Greater than 140 Aroclor PCBs can be

determined with the new column and mass spectrometry

• The seven European indicator PCBs can be determined individually

• Spectral deconvolution available with TOFMS allows qualitative identification for coeluting PCBs