Determination in Fish

The verification of the concentrations of the calibration solutions was considered to be a important aspect to achieve traceability. A pure methylmercury chloride compound was prepared for the certification, the purity of the calibrant of which was verified by C, H, Hg and Cl elemental analysis and was found to be higher than 99.8%. This compound was distributed to the participants in the certification both for calibration purposes and as a means of verification of the calibrant used in their laboratory. 

Second method about 400-500 mg of sample were treated with HCl and extracted into toluene and cysteine, and back-extracted into toluene. The extract was dried with anhydrous Na2S04. The separation was by capillary gas chromatography (column of 30 m length, internal diameter of 0.53 mm stationary phase S.P.B. 608 Supelchem, 0.50 pm film thickness injection of 1 pL temperature of the injector of 250 °C, temperature of the ECD detector of 350°C, column temperature of 90°C N2 as carrier gas at 10 mLmin Ar/ CH4 as make up gas type at 60 mLmin ). Calibration was by calibration graph with CH3HgCl in toluene C2H5HgCl was used as internal standard. 

About 50 mg were extracted with a mixture of H2S04/MeC00H in Milli-Q water (2 mL). The extract was injected in the headspace separation was by capillary gas chromatography (1 m length column with 3 mm internal diameter Chromosorb WAW 80-100 mesh loaded with 10% AT-1000 stationary phase injector temperature of 120°C, column temperature of 180 °C Ar as carrier gas at 100 mLmin ). Final detection was by atomic fluorescence spectrometry. Calibration was by standard additions, using MeHgCl in Milli-Q water as calibrant. 

About 50 mg sample was wetted with 1 mL NaCl solution (standard additions were carried out at this stage) and shaken manually for 15 min this was followed by an addition of 200 pL (sub-boiling distilled) HCl and 20 min shaking. Neutralization was performed by addition of ca. 2 mL NaOH (1 mol L ) to pH 6-7. The extraction was by addition of 1 mL buffer (pH 9) 

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Bioconcentration factors (BCF) were determined in fish samples collected in the field as well as in experimentally exposed fish in a survey conducted in the UK [12]. The experimental BCF of NP was between 90 and 125, suggesting a moderate accumulation in rainbow trout muscle. Environmental BCF values for NP in fish muscle (for gudgeon, roach and chub) were between 10 and 50. For A9PEOi+2, a maximum BCF of475 in chub liver was determined. A series of North Sea fish samples taken offshore contained no detectable APEO metabolites in liver or muscle tissue. 

Modem extraction and clean-up techniques, such as pressurised liquid extraction and microwave-assisted extraction, have almost not applied to the analysis of PFCs yet. Llorca et al. [49] reported the development and application of a PEE method for PFCs determination in fish. This technique provided rapid and accurately clean extracts for sensitive analysis. 

Trace metals (Cr, Cu, Pb, and Zn) were determined in fish and sediment samples from Lake Boeuf, Southeastern Louisiana [14]. Lake Boeuf is a popular... 

F. Ubillus, A. Algeria, R. Barbera, R. Farre, M. J. Lagarda, Methylmercury and inorganic mercury determination in fish by cold vapour generation atomic absorption spectrometry, Food Chem., 71 (2000), 529-533. 

This cold extraction method is successfully performed in our and other laboratories for more than 20 years. Because hexane is neurotoxic, isohexane or heptane can be used as a hydrophobic solvent. A modified method can also be used as a semi-micro method for the lipid determination in fish, mussels, oysters, Daphnia, and other aquatic organisms or tissues. 

Arslan Z. and Paulson A. J. (2002) Analysis of biogenic carbonates by inductively coupled plasma-mass spectroscopy (ICP-MS). Flow injection on-hne sohd-phase preconcentration for trace element determination in fish otohths. Anal. Bioanal. Chem. 372,116—7S5. 

Hypoxanthine ratio determination in fish extract using CE and immobilized enzymes IMP, HxR and Hx from cod, salmon and trout fillets Fish sample homogenized with 10% TCA, supernatant centrifuged, neutralized, diluted and filtered... 

Table 5.6 Summary of the various methods used for organoarsenical determination in fish tissue [22]...

Jerome M, Martinsohn JT, Ortega D, Carreau P, Verrez-Bagnis V, Mouchel O (2008). Toward fish and seafood traceability anchovy species determination in fish products by molecular markers and support through a public domain database. J. Agric. Food Chem., 56 3460-3469. 

Nineteen AA were detected in beer samples derivatized with napthalene 23-dicarboxaldehyde (NDA) and cyanide (CN ) by capillary zone electrophoresis (CZE) with electrochemical detection Under the optimum conditions, the limits of detection (LODs) for individual AA were between 84 and 893 amol. An interesting method recently developed by Ruiz-Jimenez and Luque de Castro reported the determination of BA in nine solid food samples using a full-automated method based on pervaporation coupled online with CE and indirect UV detection. The pervaporator allowed leaching, formation of the volatile analytes, and their removal by evaporation and diffusion through a membrane. The isolated analytes were injected online into the CE system while the solid matrix remained in the pervaporator. With this approach, BA have been determined in fish, meat, and sausage, with LODs ranging between 0.2 and 0.6 fig/mL. 

Price, D.J. 1984. Genetics of sex determination in fishes - A brief review. In Fish Reproduction Strategies and Tactics (Ed. by G.W. Potts R.J. Wootton), pp 77—90. London Academic Press. 

In the method developed by Westoo" described earlier in this section, for the identification and determination of methylmercury in fish by gas chromatography, the methylmercury was extracted with benzene from a homogenate of the fish acidified with hydrochloric acid. It was then taken up into ammonium hydroxide solution and finally re-extracted into benzene after acidification with hydrochloric acid. The extraction with alkali was incomplete unless the benzene extract was previously concentrated by distillation. The distillation procedure was assumed to remove volatile thio compounds binding part of the methylmercury and preventing its uptake into ammonia. Any methylmercury attached to a sulphur atom of nonvolatile compounds giving rise to alkali-insoluble methylmercury salts at the purification stage would not be determined. In fish from Swedish lakes and the Baltic, with total mercury contents... 

Llorca M, Farre M, Pico Y, Barcelo D. Development and validation of a pressurized liquid extraction liquid chromatography—tandem mass spectrometry method for perfluorinated compounds determination in fish. J Chromatogr A 2009 1216(43) 7195-204. 

FIGURE 4.5 MCFIA system for mercury determination in fish by cold vapor absorption spectrophotometry. AAS atomic absorption spectrometer quartz cell Ar argon carrier gas C carrier (HCl) GLS gas-liquid separator PP peristaltic pump R reducing reagent (NaBFL, in NaOH) RC reaction coil V three-way solenoid valve and W waste. 

Veciana-Nogues, M. T., M. S. Albala-Hurtado, M. Izquierdo-Pulido, and M. C. Vidal-Carou. 1996. Validation of a gas-chromatographic method for volatile amine determination in fish samples. Food Chem. 51 513-569. 

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