X-ray spectroscopy in biology and medicine. IV. A simple, indirect sensitive procedure for the determination of nitrogen (ammonia) at the microgram and submicrogram level

Preconcentration for Trace Element Determination in Aqueous Samples

“…The excess reagent is washed from the filter and the residual mercury determined by X-ray spectrometry. As little as 0.2 pg of nitrogen may be determined (55).…”

X-Ray Absorption and Emission

“…In alloys (81,289,466) In minerals and ores (295,296,386,486,490) In miscellaneous materials (289, 364) Nitrogen (300) Oxygen (210) Palladium (238) Phosphorus (23,133,145,166,209,221,229,379,397,506) Platinum (34) Plutonium (294,312) Potassium (25,145,269,284,299,379,451,484,506) Rare earth elements In minerals and ores (SOS, 458) In miscellaneous materials (202,281,443) In rare earth mixtures (168,202,405,458) Rhodium ( 238) Ruthenium (238) Scandium ( 293) Selenium (119,410) Silicon…”

“…Examples given are the determination of phenolic and unsaturated compounds by bromination, 5-chloro-8-hydroxy-7-iodoquinoline by chelation, and ammonium acetate by PbS04. An analogous approach (300) is the use of a filter paper impregnated with Nessler's reagent to react with NHS; the mercury con tent of the paper is a function of the available nitrogen (as NH3). Gofman et al studies (177)(178)(179) on the determination of 66 elements in blood are a, very ambitious undertaking.…”

“…Applications to a wide variety of X-ray emission has been widely applied in the fields of biological and clinical chemistry (6,11,46,62,109,228,293,299,300,(330)(331)(332)410). Other Class 2 applications include: trace elements extracted from bitumen, asphalt, and coal (342); thin films produced by the reaction of lubricating oil additives with metal parts (397); and the combination of electrophoresis and chromatography (495).…”