This document describes the method of determining mercury in blood and urine by cold vapor atomic absorption spectrometry (AAS) using the VGA 77. The performance of the VGA 77 for mercury determination in these solutions is presented. Various clinical manifestations of mercury intoxication may occur depending on the type of mercury involved. Inhalation of elemental mercury leads to lung, central nervous system (CNS), and kidney damage. CNS damage results in a range of behavioral and neurological deficits. Ingestion of inorganic mercurials can cause severe gastrointestinal damage due to their corrosive nature, which is more clinically significant than mercury exposure. Once absorbed, inorganic mercurials concentrate in the kidney and may cause proximal tubular necrosis. Exposure to organomercurials such as methyl mercury primarily affects the CNS and can be severe, including coma and death. Organomercurials can cross the placenta and affect the unborn child, leading to postnatal cerebral palsy. Organomercurials are typically found in the food chain as a result of methylation of inorganic mercury salts by bacteria.
The document details a laboratory procedure for analyzing mercury levels in biological fluids. It explains that the method involves oxidizing samples to produce solutions suitable for analysis with the continuous flow Vapor Generation Accessory, model VGA-77.
Specific protocols are provided for both urine and blood matrices. The urine method utilizes potassium permanganate and persulfate digestion followed by reduction with sodium borohydride. The blood method employs a mineral acid digestion mixture of nitric, perchloric, and sulfuric acids to prepare the sample for analysis.
The VGA-77 is a continuous flow device that uses a peristaltic pump to mix reagent and sample streams with an inert gas to generate volatile mercury or hydrides from solution.
The procedure requires mixing 2.00 mL of urine with specific volumes of acids and potassium permanganate.
After adding potassium persulfate, the solution must be incubated at 85-95 °C for at least 90 minutes.