PRESERVATION OF SAMPLES FOR DISSOLVED MERCURY¹

Abstract

Water samples for dissolved mercury require special treatment because of the high chemical mobility and volatility of this element. Widespread use of mercury and its compounds has provided many avenues for contamination of water. Two laboratory tests were done to determine the relative permeabilities of glass and plastic sample bottles to mercury vapor. Plastic containers were confirmed to be quite permeable to airborne mercury, glass containers were virtually impermeable. Methods of preservation include the use of various combinations of acids, oxidants, and complexing agents. The combination of nitric acid and potassium dichromate successfully preserved mercury in a large variety of concentrations and dissolved forms. Because this acid‐oxidant preservative acts as a sink for airborne mercury and plastic containers are permeable to mercury vapor, glass bottles are preferred for sample collection. To maintain a healthy work environment and minimize the potential for contamination of water samples, mercury and its compounds are isolated from the atmosphere while in storage. Concurrently, a program to monitor environmental levels of mercury vapor in areas of potential contamination is needed to define the extent of mercury contamination and to assess the effectiveness of mercury clean‐up procedures.

Preventing Mercury Vapor Release from Broken Fluorescent Lamps during Shipping

“…A review of methods for preserving water samples concluded that plastic sample bottles are highly permeable to mercury dissolved in water, whereas glass containers are essentially impermeable. 27 Permeability of oxygen, moisture, and light through food packaging materials may have some relevance to this research. Glass and metals provide the greatest protection, whereas plastics generally offer less protection, with permeability depending on the type of plastic.…”

Uji Kestabilan Kadar Merkuri pada Beberapa Larutan Pengawet

“…Kombinasi asam nitrat dan kalium dikromat berhasil mengawetkan merkuri dalam berbagai konsentrasi dan bentuk terlarut. Karena pengawet asam-oksidan ini bertindak sebagai penampung merkuri di udara dan wadah plastik permeabel terhadap uap merkuri, botol kaca lebih disukai untuk pengumpulan sampel (Hamlin, 1989).…”

“…L-Cysteine disarankan untuk digunakan bersama dengan HNO 3 sebagai pengawet larutan standar merkuri (Hamlin, 1989;Mladenova, Dakova, Tsalev, & Karadjova, 2012). Matriks cair menggunakan metode CVAAS menggunakan 10 mg L-Cysteine per liter air, sedangkan untuk matriks padatan (metode thermal decomposition) menggunakan 100 mg L-Cysteine per liter air.…”