Geology topics

J.E. Gofus

Publications and source records attributed to J.E. Gofus.

3 recordsLinked to original sources

USGS2020

Determination of malachite green and its leuco form in water

Liquid chromatographic (LC) analysis can detect malachite green residues in water at less than 10µg/L. Water samples were concentrated on disposable diol columns, eluted with 0.05M p-toluenesulfonic acid in methanol, and determined by reversed- phase LC. When combined with a lead oxide postcolumn reactor, the LC method can simultaneously determine both leuco and chromatic forms of malachite green. Recoveries averaged 95.4% for the chromatic form and 57.3% for the leuco form of malachite green oxalate and leuco malachite green in spiked pond water samples. Recoveries of the carbinol form of malachite green (an equilibrium product of the dye in water) from spiked tap water samples averaged 98.6%. Recoveries of leuco malachite green were low and pH-dependent.

Journal of AOAC International↗

USGS2020

Determination of malachite green residues in the eggs, fry, and adult muscle-tissue of rainbow-trout (Oncorhynchus-mykiss)

Malachite green, an effective antifungal therapeutant used in fish culture, is a known teratogen. We developed a method to simultaneously detect both the chromatic and leuco forms of malachite green residues in the eggs, fry, and adult muscle tissue of rainbow trout ( Oncorhynchus mykiss ). Homogenates of these tissues were fortified with [ 14 C] malachite green chloride and extracted with 1% (v/v) acetic acid in acetonitrile or in methanol. The extracts were partitioned with chloroform, dried, redissolved in mobile phase, and analyzed by liquid chromatography (LC) with postcolumn oxidation of leuco malachite green to the chromatic form. LC fractions were collected every 30 s for quantitation by scintillation counting. Recoveries of total [ 14 C] malachite green chloride residue were 85 and 98% in eggs fortified with labeled malachite green at concentrations of 0.5 and 1.00 μg/g, respectively; 68% in fry similarly fortified at a concentration of 0.65 μg/g; and 66% in muscle homogenate similarly fortified at a level of 1.00 μg/g. The method was tested under operational conditions by exposing adult rainbow trout to 1.00 mg/L [ 14 C] malachite green chloride bath for 1 h. Muscle samples analyzed by sample oxidation and scintillation counting contained 1.3 and 0.5 μg/g total malachite green chloride residues immediately after exposure and after a 5-day withdrawal period, respectively.

Journal of AOAC International↗

USGS1995

Distribution and elimination of [ 14 C] sarafloxacin hydrochloride from tissues of juvenile channel catfish (Ictalurus punctatus)

The distribution and loss of radioactivity from tissues were determined in 60 juvenile channel catfish (Ictalurus punctatus) following oral dosing with the candidate fish therapeutant Sarafin® ([ 14 C] sarafloxacin hydrochloride) at 10 mg/kg for 5 consecutive days. Twelve groups of 5 fish each were sampled at selected times ranging from 3 to 240 h after the last dose was administered, The concentration and content of sarafloxacin-equivalent activity was determined in liver, gallbladder, kidney, skin, and skinless fillet by sample oxidation and liquid scintillation counting; content of sarafloxacin-equivalent activity was determined in stomach and anterior and posterior intestines, Skinless fillet tissues were also analyzed for sarafloxacin and for potential metabolites by gradient-elution high-performance liquid chromatography (HPLC) with in-line radiometric and fluorescence detection, Loss of radioactivity from the whole body conformed to a bimodal elimination pattern with a rapid initial phase ( t 1/2 =11 h) and a slower secondary phase ( t 1/2 =222 h). Tissue and contents of the gastrointestinal tract (i.e. stomach and anterior and posterior intestines) were a principal depot of activity during the first four sample times (3, 6, 12, and 24 h); the combined head, skeleton, and fins (i.e. residual carcass) were the principal depot of activity in samples taken after 24 h. Of those tissues sampled 3 h after the last dose, relative sarafloxacin concentration was greatest in the liver (4.06 μg equivalents/g) and least in the residual carcass (1.13 μg equivalents/g), Intermediate concentrations were found in the kidney (2.04 μg equivalents/g), skinless fillet (1.71 μg equivalents/ g), and the skin (1.51 μg equivalents/g). Concentrations of sarafloxacin-equivalent residues in edible skinless fillet were consistently among the lowest of all tissues examined. The highest mean concentration of parent-equivalent material in the fillet tissue was found 12 h after administration of the last dose (2.27 μg equivalents/g) and declined thereafter, Sarafloxacin constituted between 80 and 90% of the extractable radioactive residues from the fillet homogenates. No other peaks were resolved in any of the fillet tissue samples analyzed by HPLC with in-line radiometric detection.

Aquaculture↗