phase sensitive detector described here has two principal applications: a- to produce a d.c out put proportional to- the amplitude of an incoming a,c signal and indicate, by the outut polarity, the phase of the signal with respect to an internal reference. b- to detect the presence of a signal of known phase and frequency which would otherwise be lost in «background noise» and to measure its am...

a sensitive procedure for determining total vitamin c (ascorbic acid + dehydrate ascorbic acid) in a blood drop from a finger prick, before and after the adminis- tration of a vitamin c tablet is described. analysis was carried out by high per- formance liquid  chromatography with  electrochemical detection (hplc/ec). measurements were taken one hour, two hours and six hours after the administr...