A simple ICP-MS procedure for the determination of total mercury in whole blood and urine.

A simple and sensitive procedure for total mercury in whole blood and urine using inductively coupled plasma-mass spectrometry (ICP-MS) is described. Specimens are prepared by precipitation-extraction with 50% v/v hydrochloric acid containing EDTA and cysteine, centrifuged, and filtered through fritended screening column; the filtrates are directly analyzed by ICP-MS. The method is linear between 2 and 200 micrograms/L in the specimen with an absolute sensitivity of 0.2 microgram/L in the final supernatant. The assay variability at various concentrations (microgram/L) of mercury are as follows: intra-assay whole blood (n = 20)-4.6 +/- 0.6 (c.v. 12.3%), 18.3 +/- 1.1 (c.v. 6.1%), 56.4 +/- 2.8 (c.v. 5.0%); inter-assay whole blood (n = 15)-5.7 +/- 1.0 (c.v. 16.8%), 19.7 +/- 2.7 (c.v. 13.5%), and 50.1 +/- 6.9 (c.v. 13.7%); urine (n = 20)-9.3 +/- 1.2 (c.v. 12.9%), 29.6 +/- 2.2 (c.v. 7.4%). Recovery of organic and inorganic mercury from blood samples ranges from 91.6% to 110.2%. The method is suitable for analysis of total mercury, both organic and inorganic, in whole blood and urine.     

A method for the rapid determination of serum total cholesterol using a modification of the pearson reaction

A method is described for the direct determination of total serum cholesterol using toluene-p-sulphonic acid. The method is rapid, compares well with a Bloor extraction method, gives good replicate results and requires only 0.2 ml of serum.