Renal test dyes. I

Determination of sodium and potassium in nanoliter volumes of biological fluids by furnace atomic absorption spectrometry

“…In addition, the assay value for Na or K in a 0.1-nL sample solution containing 95 mM NaCl and 15 mM KC1 was not altered by increasing the concentration of urea up to 1000 mM nor of mannitol up to 250 mM (To convert millimoles of Na or K to picograms delivered to the microboat as a 0.1-nL aliquot, use: Na mmol/L X 2.3 = pg; K mmol/L X 3.9 = pg). The lissamine green dye used to identify different parts of the renal nephron contains sodium sulfate in a variable concentration (11). The sodium concentration of most of the solutions was increased by 5-8 mM due to presence of the dye.…”