Page 14 - Shimadzu Journal vol.8 Issue2

Insight from customer / Report

Selectivity and reproducibility Nevertheless, background subtraction with the blank diesel matrix
was performed for all analyses to consider even minimum matrix
The desulphurized diesel matrix blank used for this study contained interference.
trace sulphur compounds in an overall content below 10 mg/L. It Comparing the desulphurized diesel matrix sample with hexane
showed residues of benzothiophenes and dibenzothiophenes, but solvent matrix sample, no negative matrix effects were observed.
no considerable amounts of sulfides, disulfides, mercaptans and The signals in the diesel sample are not shifted significantly as
thiophenes, which would elute within the first minutes of the against the hexane sample (fig. 3). Similar base widths for the sig-
chromatogram (fig. 2). This allowed the usage for spiking with the nals in both matrices were found, indicating no severe peak broad-
sulphur standard mix, as the matrix does not provide significant ening due to the diesel matrix. This not only allows for convenient
signal for the target compounds. The spiked components elute in comparison of diesel and hexane samples with just one processing
the early chromatogram range within 10 min, except for diben- method, but also ensures detection limits to be as good in the diesel
zothiophene, which elutes later at 22.3 min. Yet, also this target as in pure solvent, enabling sensitive, yet selective detection of the
component is nicely separated from the benzothiophenes and target compounds down to trace levels despite the high matrix load
dibenzothiophenes present in the blank diesel matrix (fig. 3). in the diesel sample.

uV
1200
1100
1000
900
800 C7+C8 benzothiophenes
700 C1, C2, C3, C4, C5, C6 dibenzothiophenes
600
C1, C2, C3, C4, C5, C6 benzothiophenes
500
400
sulfides, disulfides,
300 mercaptans, thiophenes
200
100
0
-100
-200
5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 55.0 60.0 min
Fig. 2. Chromatogram of the desulphurized diesel sample used as blank matrix

uV
1 uV
5000
3500
4500
4000 1
2 4 3500
3000 2
3 3000 3
2500
2500 2000
1500
6 1000
2000 5 500
0
1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 min
1500 7 Zoomed view
1000
500

0
5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 55.0 60.0 min
Fig. 3. Comparison view of the chromatograms for level 1 sulphur standard in desulphurized diesel matrix (black) and
hexane solvent matrix (pink), chromatograms are base shifted for better visibility

Shimadzu Journal vol.8 Issue2 56