quadrupole mass spectrometry

International Journal of Mass Spectrometry and Ion Physics, 46 (1983) 313-316 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

IDENTIFICATION JUADRUPOLE

J. 1

OF SULFUR

MASS

and

BY GAS CHROMATOGRAPHY/

SCHLUMBERGER,

0. LOYAUX' 228, rue Einstein

, 49, quai du Halage

2 NERMAG

IN A GASOLINE

SPECTROMETRY

GUIEZEI , G. DEVANT2

FLDPETROL

COMPOUNDS

313

- 92500

RUEIL

- 77530

VAUX LE PENIL

MALMAISON

FRANCE

FRANCE

ABSTRACT Sulfur compounds can be analysed in gas-oil without preliminary separation by The specific detection of sulfur low resolution quadrupole mass spectrometer. compounds is obtained when the quadrupole analyser works in negative ionization mode with ammonia as reactant gas.

INTRODUCTION Sulfur which

compounds

makes

qualitative

It was often other

that could 13CC2H8 species

only

R-CHS

compounds.

At mass

interfere M/bM

with

are

as reactant

full spectra ristic. start range.

the chemical

have a very

With

negative

APPARATUS

range

molecular

the reactant ion detection

for sulfur

increases

weight

is raised

other

of 3400,

CHS'

the selectivity peak

ionic is totally

background

noise

occurs

45.

using mode

the

is characte-

and it is necessary

the H2S molecular much

no background

compounds

resolve

In this ionization

34 a.m.u.,

gas produces

species 2+ (C7H6) and

are background

ion as the base

low molecular

below

(1,2,4).

is 2 x M = 100 at mass

analyser

ion monitoring.

task.

other

Only CHS+,

At a resolution mass

seven

the others

to completely

ionization

The pseudo

acquisition

ion detection

and sensitivity

mass.

gas and single

But mercaptans

positive

required

(3)

is one of the fragments

are at least

All

difficult

spectrometers

which

resolution.

the sample.

low concentration

a rather

mass

fragment

there

of a quadrupole

are simple.

the mass

45,

at low mass

from

the same nomina

The resolution

At low resolution, ammonia

CHS+

issued

at very

determinations

the CHS+

is the resolution

have

are found

high resolution

to measure

which

isolated.

to work with

was

fragments

impurities.

fractions

and quantitative

necessary

The principle among

in gas-oil

to

weight.

noise

With

at low mass

at low mass

range

(5).

and METHOD

APPARATUS Sample

: gasoline,

the range exceed

condensed

of Cl to C26

2 % in weight

product

in which

0

natural

concentration

- 0.5 microliter

OOZO-7381/83/0000-0000/$03.00

from

gas containing

of sulfur

is injected

1983 Elsevier Scientific

hydrocarbons

compounds

in each

run.

Publishing Company

does

not

in

314

: GIRDEL

Apparatus

32 Gas

associated

to a SIDAR

and EI/CI

ion source.

Chromatograph.

111 B Data

NERMAG

System.

R lo-10

C Mass

Spectrometer

GC/MS

It is a standard

interface

METHOD Chromatographic - Fused

conditions

silica

CPSIL

- Split/splitless - He carrier The GC/MS Mass

Electron 1.000

injector

impact

multiplier

is 300"

: mass

Ionization

: The

focusing

potentials

are

conversion

The

source

hexane

dynode

pressure

impact

hydrocarbons. negative

next

is set at 3,6

is optimized

Positive

the mercaptans.

chemical

gas

KV. Scan

Only

on the chromatogram

C, 3" C/min.

ionization

of the negative a few cyclic (fig. 3),

from

chemical the

the repeller

and mass

with

KV, the

range

chain

of linear

similar

C.

as in EI mode.

of butanethiol,

Ionization

and

is 100"

P = 10-l Torr

Chemical

non-saturated but

101/400

at 3,6

temperature

solution

is very

different

dynode

(99,8),

times

and negative

and

and 101/400

is 120" C.

ion source

standard

sec. sec.

the first

is ammonia

to B. The

0.200

the characteristic

is totally

peaks

vent. is 250" C.

is 20/290"

time 0.070

temperature

with

(above)

appears

CI which

chromatographic

present

a scan

then 33/100

is set at 70 eV,

reactant

tuned

mode

splitter

temperature

temperature

selectivity of sulfur compounds -1 and P = 2.10 Torr in positive ion mode.

In electron

from

with

10 min

ion source

RESULTS and DISCUSSION _F,,gure 1 : electron impact

The

70 ml/min.

Injector

to the maximum

ion mode

unlike

and 0.3 mm i.d.

with

the oven

33/100

energy

Chemical

mode

1.2 bar.

C and

during

at 1,7 KV. The

- 25 m/L

:

range

sec.

The electron

The

pressure

conditions

: 0.400

column

in splitter

inlet

interface

time sec.

5 capillary

gas with

Spectrometer

a scan

:

1 %, in

in negative

(below). satured

to EI mode,

it.

ionization

come

hydrocarbons

isotopic

ratio

essentially are also

(M + 2) of

315 sulfur The

M-l

spectra the + 75

compounds

show

with

negative

ion as base chemical

sum of the following (C3H8S)

+ 89

peaks

Fig

(fig.

the two families

is characteristic The

(C5H12S]

in related

reconstructed

: 33 (H2S) + 47 (CH3SH)

+ 103

mass

chromatogram

+ 61

+ i17 (C6H14S}

of compounds.

(CH3 - CH2

containing

is

- SH)

only

the

4)

Fig 4 E I+

automatic

integration

the different

mercaptans

of the sulfur

compounds

which

we can assume

200 ng/

1 in our sample.

ion source

of the chromatogram (Table

tation,

that

retention

one mercaptan

Its concentration a poor

EI+

The time

5

figure full

39

using

of the sample.

the full

in EI

in EI mode

Here,

43

in negative

for example, (Fig.

and its retention

Fig 6 71

EI+ 104

61 I

I CI-

NH3

N H3

I ‘.I 10 20

,

1

30

40

50

60

I

1

40 60 80

1h

100

.

J

140

,

is

is 4 ng in the

spectra

mode.

quanti-

detected

peaks.

:

33

ratio

of

quantity

Without

: one pentanethiol

of the mercaptans

43

the ratio

of one mercaptan

the split

5 shows

of hydrocarbon

4) indicates

27 and 1 % of the total

quantity

spectra

I II II. c I-

: between

quantity

is the highest

Fig

(Fig.

is 2 % in weight

is identified

density

2)

the smallest

This

spectrometer.

and the same

contains

peak

ionization.

ions

(C4HICS)

between

3

91

Only

a difference

pseudo-molecular

mercaptans

The

can

,

180

’

CI mode H2S.

6) time

zone

316 Our

sample

did not captain

thiophene,

dithioethers

same analysis each

peak

dithiol

nor aromatic

and 2,5 dimethyl

on this artificial

thioether.

thiophene

sample

is shown

Therefore

we added

at 1 %, in the sample. in fig.

7 and full

The

spectra

of

in fig. 8

Fig 7

1 I

PELK

CRiA

HEIGHT

1

49

91

TOP(XAN, 82

TOP(RT) 0:49

i

19

36

92

0:55

3

99

221

112

I:07

4

113

ml

135

I:21

5

9

13

160

1:36

6

53

67

170

I:42 2:22

6

95

99

235

10

46

15

320

3:14

12

9

7

408

4:07

Ii

235

91

434

4:23

12

45

54

454

4:35

16

28

14

602

6:07

l@

214

77

786

a:00

PEAK

Negative almost

ion chemical

combletely

in intense

peaks.

mercaptans, mass

ionization

Single and

HZ5 CH3SH

3

C2H5SH

,-5

UH7SH

6-8-10

C5H95H

12-13-14-16

CSHllSH

18

C6H135H

mode,

the hydrocarbons

dithiols

I 2

using

ammonia

TIC pattern,

ion monitoring thioethers

and

all sulfur

isotopic

in gasoline

as reactant

using

compounds

abundance

spectrometer.

ARPINO Rev.

2

P., SCHMITTER

J.M.,

Inst. Francais

SELVES

J.L.

1978,

33, 467

J.L.

Analysis,

1980,

v. 8, no 9 p. 410-421

3

RALI

H-T.,

THOMSON

U.S.

Dept.

of Interior

4

GALLEGOS Analytical

5

SELVES

du Petrole,

- Bureau

H-J.,

HOPKINS

of Mines,

Bull

E.J. Chemistry,

KNOF H., LARGE Analytical

COLEMAN

C-J.,

Vol.

R., ALBERS

Chemistry

47, n" 7, June G.

- 1976,

4P, 2120

1975

R.L. 659,

1972

occurring

can detect

a low resolution

REFERENCES 1

gas eliminates

quadrupole