Common methods for determining mineral absorption by the body are invasive and frequently utilize radioisotopes. In experiment one. rats were given a dose of radiolabeled ferrous sulfate. Relative absorption was estimated by changes in serum iron and by appearance of the radiotracer in the serum. There were no differences in relative absorption determined by the methods, although the low overall absorptions by the iron-replete rats may have decreased the sensitivity. In experiments two and three. iron and magnesium supplements were given orally to 12 women age 19-25. Each subject received iron and magnesium supplements once each week for 5 weeks. Blood samples were taken via venous catheter every 30 minutes for 2 hours and 30 minutes following dosing, and a urine sample was taken following the collection time period. Samples were analyzed for serum iron, serum magnesium, hematocrit, ferritin, urinary magnesium, and urinary creatinine. The increase in serum iron was evaluated from both the peak increase in serum iron and from the integrated increase in serum iron over the blood collection time. The data for each supplement were compared by analysis of variance. For the iron supplements. the taste-free iron supplement increased serum iron less than either the Ferrochel or the ferrous sulfate supplements. When the iron absorption was then compared to ferritin stores (low, medium, and high), the relative absorption of Ferrochel was higher in the low ferritin range (0-15 ng/ml) than in the upper ranges (P=.00l for peak and P=.0002 for area). Relative absorption from Ferrochel iron was also higher than the other supplements for subjects with low ferritin stores. Neither serum nor urinary magnesium values differed significantly among the three compounds examined. Serum magnesium values are stable in healthy individuals, and the urinary magnesium data were not evaluated over 24 h as in typical magnesium load tests. In summary, both the ferrous sulfate and Ferrochel supplements were absorbed more efficiently than the taste-free iron supplement. The Ferrochel was also absorbed more efficiently in individuals with low iron stores, demonstrating better regulation by the body than with the other supplements examined.

Rapid, portable detection of biological threat agents such as Bacillus anthracis endospores (“spores”) is extremely important given the real and perceived threats of bioterrorism. Gas chromatography-mass spectrometry (GC-MS) is an excellent general means for chemical detection, although special sample preparation and specialized equipment are required to employ GC-MS for detecting biological agents such as spores in the field. A GC sample introduction probe consisting of a helical wire that can be retracted inside a syringe needle, called a coiled wire filament (CWF), was employed as a simple, passively-heated means to introduce the mixture of spores plus reagents for thermochemolysis methylation (TCM) into the pre-heated GC inlet. There, reactions between spore biomarkers and the TCM reagent mixture occur between 250-290°C. At these conditions, monomethyl sulfate salt mixtures are convenient and efficient TCM reagents for the rapid conversion of a key unique spore biomarker, dipicolinic acid (DPA), to its dimethyl ester (Me2DPA). By this process, Me2DPA yields from spores were quantitatively assessed for different combinations of tetramethylammonium hydroxide (TMA+OH−), sodium hydroxide (Na+OH−), and hydrogen monomethyl sulfate (H+MeSO4−). The best reagent mixture was found by varying the combinations of the ions within the neutral or basic system containing TMA+, Na+, OH−, and MeSO4− according to a novel scheme for design of experiments termed ionic mixtures design of experiments (IMDOE). A combination of the above ions was found that is near-quantitative in its methylation of DPA to Me2DPA; this mixture contained a 1:3:1:3 mole ratio of TMA+:Na+:OH−:MeSO4−. This yield of Me2DPA was approximately a ten-fold increase over the best performance observed at the same conditions with tetramethylammonium hydroxide alone, the TCM reagent widely-used for GC. The reactions involving MeSO4− and TMA+ as methylating reagents, plus relevant hydrolysis and methylation reactions involving acid and base plus water and methanol, were investigated. An overall model is presented and mechanisms are proposed for reasons why basic mixtures of MeSO4− salts are more effective in methylating DPA compared to TMA+ salts at the conditions employed.