This evidence shirt illustrates the presence of nitrites with a positive test for gun shot residue. The chemistry involved is the same used in the microbiology laboratory to detect nitrate (NO₃) reduction to nitrite (NO₂).  (J. Scott Doyle, Jefferson Regional Forensic Lab, Louisville, KY)

This positive Greiss test illustrates the presence of nitrites. The chemistry involved is the same used in the microbiology laboratory to detect nitrate (NO₃) reduction to nitrite (NO₂).  (J. Scott Doyle, Jefferson Regional Forensic Lab, Louisville, KY)

Uninoculated tube illustrating the proper filling of nitrate and nitrite broth. (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Nitrate reagents A and B. (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Zinc dust. (Rebecca Buxton, University of Utah, Salt Lake City, UT)

“Dirtying” a stick with zinc dust. (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Addition of zinc dust to a nitrate test to force the reduction of the substrate. (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Addition of zinc dust to a nitrate test to force the reduction of the substrate. (Labeled view) (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Negative nitrate reaction after the addition of reagents A and B. (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Negative nitrate reaction after the addition of reagents A and B and zinc dust. (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Negative nitrite reaction after the addition of reagents A and B. (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Pseudomonas aeruginosa growing in nitrate and nitrite broths before the addition of reagents, illustrating gas production. (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Pseudomonas aeruginosa growing in nitrate (tube labeled NO₃) and nitrite (tube labeled NO₂) broths before the addition of reagents, illustrating gas production. (Labeled view) (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Pseudomonas aeruginosa growing in nitrate and nitrite broths after the addition of reagents A and B. (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Pseudomonas aeruginosa growing in nitrate (tube labeled NO₃) and nitrite (tube labeled NO₂) broths after the addition of reagents A and B. (Labeled view) (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Pseudomonas aeruginosa growing in nitrate and nitrite broths after the addition of reagents A and B and zinc dust. (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Pseudomonas aeruginosa growing in nitrate (tube labeled NO₃) and nitrite (tube labled NO₂) broths after the addition of reagents A and B and zinc dust. (Labeled view) (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Moraxella catarrhalis growing in nitrate and nitrite broths before the addition of reagents. (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Moraxella catarrhalis growing in nitrate (tube labeled NO₃) and nitrite (tube labeled NO₂) broths before the addition of reagents. (Labeled view)  (Rebecca Buxton, University of Utah, Salt Lake City, UT)

Moraxella catarrhalis growing in nitrate and nitrite broths 24 hours after the addition of reagents A and B. (Rebecca Buxton, University of Utah, Salt Lake City, UT)