JOURNAL OF LIMNOLOGY DOI: 10.4081/jlimnol.2017.1691 SUPPLEMENTARY MATERIAL Chlorophyll a interference in phycocyanin and allophycocyanin spectrophotometric quantification Rosaria LAUCERI,1* Mariano BRESCIANI,2 Andrea LAMI,1 Giuseppe MORABITO1 1National Research Council of Italy, Institute for the Study of Ecosystems, Largo Tonolli 50, 28922 Verbania-Pallanza 2National Research Council of Italy, Institute for Electromagnetic Sensing of the Environment, Optical Sensing Group, via Bassini 15, 20133 Milan, Italy *Corresponding author: [email protected] (A) (B) 80 70 600 60 500 50 40 400 30 E% E% 300 20 10 200 0 100 -10 -20 0 0.00 0.01 0.02 0.03 0.04 0.05 0.000 0.005 0.010 0.015 PC (mg/mL) APC (mg/mL) Supplementary Fig. 1. Errors % in PC (A) and APC (B) concentration before and after correcting 620 620 675 absorbance at 620 nm and 652 nm with equations: A Phs = 1.014 A measured – 0.242 A measured 652 652 675 and A Phs = 1.035 A measured – 0.231 A measured. Green bullets refer to E% in phycobiliprotein quantification observed when Bennet and Bogorad equations were directly used without correcting Chla interference. Red bullets refer to E% in phycobiliprotein quantification observed after correcting the absorbance of PC and APC from Chla contribution before applying Bennet and Bogorad equations. After correction the error in phycobiliprotein determination varied from -19.1% to 0.7% for PC and from 5.8% to 75.8% for APC. 2 (A) 80 (B) 70 600 60 500 50 400 40 300 E% 30 20 E% 200 10 100 0 -10 0 -20 -100 0.00 0.01 0.02 0.03 0.04 0.05 0.000 0.005 0.010 0.015 PC (mg/mL) APC (mg/mL) Supplementary Fig. 2. Errors % in PC (A) and APC (B) concentration before and after correcting 620 620 675 absorbance at 620 nm and 652 nm with equations: A Phs = 1.015 A measured – 0.256 A measured 652 652 675 and A Phs = 1.042 A measured – 0.282 A measured. Green bullets refer to E% in phycobiliprotein quantification observed when Bennet and Bogorad equations were directly used without correcting Chla interference. Red bullets refer to E% in phycobiliprotein quantification observed after correcting the absorbance of PC and APC from Chla contribution before applying Bennet and Bogorad equations. After correction the error in phycobiliprotein determination varied from -12.3% to 1.9% for PC and from -69.8% to 0.5% for APC. 3 (A) (B) 80 650 70 60 550 50 450 40 350 30 E% 20 E% 250 10 150 0 -10 50 -20 -50 0.00 0.01 0.02 0.03 0.04 0.05 0.000 0.005 0.010 0.015 PC (mg/mL) APC (mg/mL) Supplementary Fig. 3. Errors % in PC (A) and APC (B) concentration before and after correcting 620 620 675 absorbance at 620 nm and 652 nm with equations: A Phs = 1.014 A measured – 0.246 A measured 652 652 675 and A Phs = 1.041 A measured – 0.271 A measured. Green bullets refer to E% in phycobiliprotein quantification observed when Bennet and Bogorad equations were directly used without correcting Chla interference. Red bullets refer to E% in phycobiliprotein quantification observed after correcting the absorbance of PC and APC from Chla contribution before applying Bennet and Bogorad equations. After correction the error in phycobiliprotein determination varied from -9.2% to 2.5% for PC and from -42.3% to 1.6% for APC. 4 .