Foxtail millet-derived highly fluorescent multi-heteroatom doped carbon quantum dots towards fluorescent inks and smart nanosensors for selective ion detection

Foxtail millet-derived highly fluorescent nitrogen/sulfur/phosphrous (N/S/P) co-doped CQDs were efficiently fabricated via a green strategy, and were found to hold potential towards fluorescent inks and smart detection.

Clinical Applications of Gas Chromatograph/Mass Spectrometer/Computer Systems

Gas chromatograph/mass spectrometer/computer systems can be used to quantify a wide variety of compounds of clinical interest. A quadrupole instrument operated in the chemical ionization (Cl) mode was used in these studies. Because of the sensitivity and specificity of selective ion detection, it is possible to make measurements routinely in the nanogram to picogram range, with 0.1-1.0 ml samples of plasma and 1-5 ml samples of urine. Internal standards, preferably stable-isotopelabeled compounds, were added to the biological samples before isolation was begun. We describe clinical applications of these procedures to problems in toxicology, pharmacokinetics, and perinatal pharmacology.

Isolation of Drugs and Drug Metabolites from Biological Fluids by Use of Salt-Solvent Pairs

Simple rapid procedures based on salt-solvent pairs have been developed for the isolation of drugs and drug metabolites from urine, plasma, and breast milk. The best overall recovery of drugs (84-104%) was obtained by using ammonium carbonate—ethyl acetate extraction. Internal standards were added to the biological samples before the isolation procedure was begun; standards labeled with stable isotopes were preferred. The isolated drugs were quantitated by selective ion detection, with use of an LKB 9000-PDP 12 in electron impact mode, a Finnigan 1015-PDP 8/1 in chemical ionization mode, and an atmospheric pressure ionization mass spectrometer. Sensitivity of detection was in the nanogram to picogram range.

Use of Stable Isotopes in Measuring Low Concentrations of Drugs and Drug Metabolites by GC—MS—COM Procedures

Certain drugs in urine, plasma, breast milk, and amniotic fluid have been quantitatively analyzed in the picogram to nanogram range by selective ion detection with two gas chromatograph—mass spectrometer—computer systems: an LKB 9000/PDP 12 operated in the electron impact mode and a Finnigan 1015/PDP 8/I operated in the chemical ionization mode. With the latter system, it is possible to monitor several drugs and drug metabolites and an internal standard in a single temperature-programmed analysis. Internal standards labeled with stable isotopes are preferred for selective ion detection. Diphenylhydantoin-2,4,5-13C has been used to quantify diphenylhydantoin, and pentobarbital-2,4(6) ,5-13C has been used to quantify amobarbital, secobarbital, caffeine, meperidine ("Demerol"), and phenobarbital in 50-200 µl samples of plasma and breast milk.