[1] [1] L. M. Nollet, Handbook of water analysis. Japan: Food Science and Technology, 2000.

[2] [2] B. Timmer, W. Olthuis, and A. V. D. Berg, “Ammonia sensors and their applications—a review,” Sensors and Actuators B: Chemical, 2005, 107(2): 666-677.

[3] [3] C. McDonagh, C. S. Burke, and B. D. MacCraith, “Optical chemical sensors,” Chemical Reviews, 2008, 108(2): 400-422.

[4] [4] O. S. Wolfbeis, “Fiber-optic chemical sensors and biosensors,” Analytical Chemistry, 2008, 80(12): 4269-4283.

[5] [5] A. R. Firooz, M. Movahedi, and A. A. Ensafi, “Selective and sensitive optical chemical sensor for the determination of Hg (II) ions based on tetrathia-12-crown-4 and chromoionophore I,” Sensors and Actuators B: Chemical, 2012, 171-172(8): 492-498.

[6] [6] Y. Wang, B. Li, L. Zhang, L. Liu, O. Zuo, and P. Li, “A highly selective regenerable optical sensor for detection of mercury (II) ion in water using organic–inorganic hybrid nanomaterials containing pyrene,” New Journal of Chemistry, 2010, 34(9): 1946-1953.

[7] [7] K. T. Lau, S. Edwards, and D. Diamond, “Solid-state ammonia sensor based on Berthelot’s reaction,” Sensors and Actuators B: Chemical, 2004, 98(1): 12-17.

[8] [8] S. Tao, L. Xu, and J. C. Fanguy, “Optical fiber ammonia sensing probes using reagent immobilized porous silica coating as transducers,” Sensors and Actuators B: Chemical, 2006, 115(1): 158-163.

[9] [9] T. Abel, B. Ungerbock, I. Klimant, and T. Mayr, “Fast responsive, optical trace level ammonia sensor for environmental monitoring,” Chemistry Central Journal, 2012, 6(1): 21777-21778.

[10] [10] K. Waich, T. Mayr, and I. Kilmant, “Fluorescence sensors for trace monitoring of dissolved ammonia,” Talanta, 2008, 77(1): 66-72.

[11] [11] R.W. Sabnis, Handbook of biological dyes and stains. New York: Wiley, 2010.