Abstract:

Deep sea organisms were dosed with a series of concentration gradient of single hydrocarbon 1-methyl naphthalene. Water samples (10 ml) were taken from each dosing chamber at T0 (beginning of experiment) and T48 (end of experiment). Samples were extracted with 10 ml dichloromethane and then analyzed by Aqualog Horiba for 1-methyl naphthalene. Calibration curve was made using standard (96-97%) 1-methyl naphthalene. Data from Horiba aqualog was confirmed by GCMS.

Suggested Citation:

Gopal Bera Anthony Knap. 2017. DETOX 1: Concentration of 1-methyl naphthalene in dosing chambers of deep sea organisms. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7833QD4

Purpose:

Measurements of 1-methyl naphthalene in dosing chambers were made in order to calculate the LC-50 and critical body burden (CBB).

Data Parameters and Units:

Dosing were done on five different species: Jenicella, Euphausids, Systellaspis, Sergestes, and Sergia. Dosing were done at five different concentration levels: Control, 300, 600, 1200 and 2400 ug/L. Samples were taken at time zero (T0) and at the end of the experiment (T48). Concentration of 1-methyl naphthalene are in ug/L.

Methods:

Horiba Aqualog: Estimated total oil equivalent (EOE) were calculated from total scanning fluorescence (TSF) which was measured with an Aqualog Horiba Fluorometer (Model). First, the TSF was measured for 1-methyl naphthalene and the optimal wavelengths for maximum intensity (MI) was established. A 5-7 points calibration curve was made using diluted standard of 1-methyl naphthalene with concentration ranges from 10 mg/L to 0.5 mg/L. Then 10 ml sample was extracted with methylene chloride and the extract was measured for TSF. MI at established optimal wavelengths was used to get the EOE using the equation from calibration curve at best fit. GCMS: The analytical procedure used for the measurement of polycyclic aromatics (PAHs) were based on established GERG SOPs. Briefly, 1L of water samples were extracted in duplicate by solvent partition against small volumes (100 ml) of dichloromethane (DCM) after the appropriate additions of surrogate standards (e.g., d8-naphthalene, d10-acenaphthene, d10-phenanthrene, d12-chrysene, and d12-perylene). After extraction, duplicate sample extracts were reduced to approximately 1 and 0.1 mL and spiked with appropriate amounts of deuterated compounds as internal standards (e.g., d10-Fluorene and d12-Benzo(a)pyrene). PAHs were quantitatively analyzed by gas chromatography with mass spectrometric detection (Agilent 6890N GC/5975C inert MSD) in the selected ion mode (SIM) using a 30 m x 0.25 mm i.d. (0.25 µm film thickness) DB-5 fused silica capillary column (J&W Scientific, Inc.). The oven temperature was programed from an initial temperature of 60°C to 300°C at 12°C min-1 and held at this temperature for 6 min. The molecular ions for each target PAH were used for quantification. The mass spectral data were acquired, and the molecular ions for each of the PAH analytes were used for quantification. The gas chromatograph/mass spectrometer (GC/MS) was calibrated by the injection of standards at five different concentrations. Analyte identification was based on the retention time of the quantitation ion for each compound and a series of confirmation ions.

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