Monitoring nitrite with optical sensing films

A new, low-cost nitrite sensor was developed by immobilizing a direct indicator dye in an optical sensing film for food and environmental monitoring. This sensor was fabricated by binding Safranine 0 to a cellulose acetate film that had previously been subjected to an exhaustive base hydrolysis. The membrane has good durability (>12 months) and a short response time (<8 s). Nitrite can be determined for the range of 0.005-2.00 mug ml(-1) with 3delta detection limits of 0.001 mug ml(-1). The method is easy to perform and uses acetylcellulose as a carrier. The reagents used for the activity of the cellulose support are inexpensive, non-toxic and widely available. (C) 2002 Elsevier Science B.V. All rights reserved.