Straight-Chain Hydrocarbons - American Chemical Society

substance meets ACS Standard-Grade specifications including: Identity by Gas Chromatography−Mass Spectrometry,. Identity by Relative Retention ... T...
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Monograph pubs.acs.org/doi/book/10.1021/acsreagents

Straight-Chain Hydrocarbons Part 5, Assay and Identification of Standard-Grade Reference Materials: Specifications and Tests eISBN: 9780841230460 Tom Tyner Chair, ACS Committee on Analytical Reagents James Francis Secretary, ACS Committee on Analytical Reagents

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ABSTRACT This ACS Reagent Chemicals Standard-Grade Reference Materials monograph for Straight-Chain Hydrocarbons, in addition to common physical constants, details the following specifications and corresponding tests for verifying that a substance meets ACS Standard-Grade specifications including: Identity by Gas Chromatography−Mass Spectrometry, Identity by Relative Retention Index, and Assay by Gas Chromatography.

SPECIFICATIONS Identity by Gas chromatography−mass spectrometry. . . . . Passes test Relative retention index . . . . . . . . . . . . . . . Passes test

Assay by Gas chromatography (using two methods) . . . . ≥98.0%

TESTS Identity by Gas Chromatography−Mass Spectrometry Analyze the sample by gas chromatography–mass spectrometry using method GCMS−SCHC1 described below. Method GCMS−SCHC1 Ionization Mode . . . . . . . . . . . . . . . . . . . . Electron ionization/70 eV Column . . . . . . . . . . . . . . . . . . . . . . . . . . 5% Diphenyl–95% dimethylpolysiloxane, 30 m × 0.25 mm i.d., 0.25 µm film thickness Temperature Program. . . . . . . . . . . . . . . . . 35 °C for 5 min, then 30 °C/min to 320 °C, then hold 5 min Carrier Gas . . . . . . . . . . . . . . . . . . . . . . . Helium at 1 mL/min Injector . . . . . . . . . . . . . . . . . . . . . . . . . Split/splitless (100:1 split) Injector Temperature . . . . . . . . . . . . . . . . . 250 °C Scan Range . . . . . . . . . . . . . . . . . . . . . . . 32–600 amu Sample Size . . . . . . . . . . . . . . . . . . . . . . . 1 µL of a 1000 µg/mL solution

© 2017 American Chemical Society

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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.

DOI:10.1021/acsreagents.5013 ACS Reagent Chemicals, Part 5

ACS Reagent Chemicals

Monograph

pubs.acs.org/doi/book/10.1021/acsreagents

The identifying ions for the compound listed in Table 5-12 must be present. The spectrum is compared to the NIST standardized library of compounds, if available. Ions in the test spectrum must match those found in the NIST spectrum.

Downloaded by CORNELL UNIV on June 15, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.5013

Table 5-12. Straight-Chain Hydrocarbons Compound Data

Name

CAS No.

Chemical Formula

Formula Weight

MS (m/z) MS (m/z) MS (m/z) Relative MS-1 MS-2 MS-3 Retention

Decane

124-18-5

C10H22

142.29

43

142

57

1.000

Docosane

629-97-0

C22H46

310.61

43

57

71

1.578

Dodecane

112-40-3

C12H26

170.34

43

170

57

1.132

Dotriacontane

544-85-4

C32H66

450.88

43

57

71

1.989

Eicosane

112-95-8

C20H42

282.56

57

282

71

1.503

Heneicosane

629-94-7

C21H44

296.58

43

57

71

1.541

Hentriacontane

630-04-6

C31H64

436.85

43

57

71

1.927

Heptacosane

593-49-7

C27H56

380.75

43

57

71

1.752

Heptadecane

629-78-7

C17H36

240.48

57

240

71

1.382

Heptane

142-82-5

C7H16

100.21

43

100

71

0.528

Heptatriacontane

NA

C37H76

521.02

43

57

71

2.514

Hexacosane

630-01-3

C26H54

366.72

43

57

71

1.718

Hexadecane

544-76-3

C16H34

226.45

57

226

71

1.337

Hexane

110-54-3

C6H14

86.18

57

86

43

0.268

Hexatriacontane

630-06-8

C36H74

506.99

43

57

71

2.362

Nonacosane

630-03-5

C29H60

408.80

43

57

71

1.828

Nonadecane

629-92-5

C19H40

268.53

57

268

71

1.465

Nonane

111-84-2

C9H20

128.26

43

128

57

0.913

Octacosane

630-02-4

C28H58

394.77

43

57

71

1.788

Octadecane

593-45-3

C18H38

254.50

57

254

43

1.424

Octane

111-65-9

C8H18

114.23

43

114

85

0.791

Octatriacontane

7194-85-6

C38H78

535.04

43

57

71

2.666

Pentacosane

629-99-2

C25H52

352.69

43

57

71

1.684

Pentadecane

629-62-9

C15H32

212.42

57

212

71

1.291

Pentatriacontane

630-07-9

C35H72

492.96

43

57

71

2.243

Tetracontane

4181-95-7

C40H82

563.10

43

57

71

3.097

Tetracosane

646-31-1

C24H50

338.66

43

57

71

1.649

Tetradecane

629-59-4

C14H30

198.39

43

198

57

1.241

Tetratriacontane

14167-59-0

C34H70

478.93

43

57

71

9.88

Triacontane

638-68-6

C30H62

422.83

43

57

71

1.874

Tricosane

638-67-5

C23H48

324.64

43

57

71

1.614

Tridecane

629-50-5

C13H28

184.37

43

184

57

1.189

Tritriacontane

630-05-7

C33H68

464.91

43

57

71

2.060

Undecane

1120-21-4

C11H24

156.31

43

156

57

1.070

© 2017 American Chemical Society

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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.

DOI:10.1021/acsreagents.5013 ACS Reagent Chemicals, Part 5

ACS Reagent Chemicals

Monograph

pubs.acs.org/doi/book/10.1021/acsreagents

Identity by Relative Retention Index

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Prepare a solution by adding equal amounts of the sample and n-decane in a suitable solvent for a final concentration of 500 µg/mL. Analyze the sample by gas chromatography using method GC–SCHC1 described below. Method GC−SCHC1 Column . . . . . . . . . . . . . . . . . . . . . . . . . . 5% Diphenyl–95% dimethylpolysiloxane, 30 m × 0.53 mm i.d., 1.5 µm film thickness Detector . . . . . . . . . . . . . . . . . . . . . . . . . Flame ionization Detector Temperature . . . . . . . . . . . . . . . . 300 °C Injector . . . . . . . . . . . . . . . . . . . . . . . . . Splitless Injector Temperature . . . . . . . . . . . . . . . . . 250 °C Sample Size . . . . . . . . . . . . . . . . . . . . . . . 1 µL Carrier Gas . . . . . . . . . . . . . . . . . . . . . . . Helium at 5 mL/min Temperature Program. . . . . . . . . . . . . . . . . 35 °C for 5 min, then 30 °C/min to 320 °C, then hold 10 min Calculate the relative retention time of the sample versus n-decane by dividing the retention time of the sample by the retention time of n-decane. Assayed values must be within 1% of the stated values in Table 5-10.

Assay by Gas Chromatography Analyze the sample by gas below. Method GC–SCHC2 Column . . . . . . . . . . . . . Detector . . . . . . . . . . . . Detector Temperature . . . Injector . . . . . . . . . . . . Injector Temperature . . . . Sample Size . . . . . . . . . . Carrier Gas . . . . . . . . . . Temperature Program. . . .

chromatography using method GC–SCHC1 described above and method GC–SCHC2 described

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. 100% Dimethylpolysiloxane, 25 m × 0.25 mm i.d., 0.25 µm film thickness . Flame ionization . 300 °C . Split/splitless (100:1 split) . 250 °C . 1 µL of a 1000 µg/mL solution . Helium at 5 mL/min . 35 °C for 5 min, then 30 °C/min to 320 °C, then hold 10 min

Measure the area under all peaks (excluding the solvent peak), and calculate the analyte content in area percent.

© 2017 American Chemical Society

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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.

DOI:10.1021/acsreagents.5013 ACS Reagent Chemicals, Part 5