3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
When analysing a samples containing arsenobetaine
(AsB) it is necessary to analyse the sample twice, once with
the UV lamp switched off and once with it switched on. This
is due to the fact that AsB coelutes with arsenite. If the UV
lamp is off AsB don’t react with naBH 4 and don’t give a
signal.
Results and Discussion
T o t a l A r s e n i c C o n c e n t r a t i o n s
The total arsenic concentrations in fish muscle are summarized
in Table I. These results are lower than limits given
by legislative of Czech Republic. All samples were also measured
by atomic absorption spectrometry with hydride generation
to ensure quality results. Results obtained by HG-AAS
were comparable to HG-AFS results.
Table I
Total arsenic concentrations in the investigated samples
determined by AFS
Sample Total arsenic [μg kg –1 ] RSD [%]
Salmon 1 186 2
Salmon 2 741 4
Trout 1 968 0
Trout 2 966 1
Trout 3 618 4
Tunny 2059 1
S p e c i a t i o n A n a l y s i s o f A r s e n i c
The influence of pH of mobile phase on the separation
efficiency has been investigated. The pH values were
in the range of pH 4–8. The best results were obtained with
pH 6.1. Separation of the five arsenic standards is shown in
the Fig. 1.
Typical chromatogram of fish extract (Thunnus atlanticus)
is presented in Fig. 2. All analysed samples of fish contained
only non-toxic arsenobetaine.
The results of the speciation analysis are shown in the
Table II. Comparision with total arsenic content reveals that
extraction efficiencies ranged from 66 to 106 %.
Fig. 1. Standard chromatogram of five arsenic species
s816
Fig. 2. Peak of arsenobetain in the chromatogram of tunny
Table III
Arsenobetaine concentrations in the investigated samples
determined by HPLC-UV-HG-AFS
Sample Extractable arsenic [μg kg–1 ] RSD [%]
Salmon 1 170 9
Salmon 2 783 4
Trout 1 714 0
Trout 2 644 1
Trout 3 407 4
Tunny 1760 2
Conclusions
Amount of total arsenic in the samples was lower than
limits for arsenic given by legislative of Czech Republic.
Arsenic was present in the form of nontoxic arsenobetaine in
all analysed samples of fish.
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