Nile Red Staining for Oil Determination in Microalgal Cells: A New Insight through Statistical Modelling

Table 2

Factorial experimental design matrix and values of the observed fluorescence intensity (also referred to as experimental results). Fluorescence intensity was determined at excitation wavelength of 530 nm, emission wavelength of 607 nm, and 15 min poststaining time.

Experiment number	Microalgal cell concentration	Ultrasonication power	Incubation temperature	Nile red dye concentration	Observed fluorescence intensity (afu)
1	0	−1	−1	−1	—
2	0	−1	−1	0	62.07
3	0	−1	−1	1.5	72.41
4	0	−1	0	−1	—
5	0	−1	0	0	63.52
6	0	−1	0	1.5	90.99
7	0	−1	1	−1	—
8	0	−1	1	0	90.60
9	0	−1	1	1.5	152.14
10	0	0	−1	−1	—
11	0	0	−1	0	44.83
12	0	0	−1	1.5	70.69
13	0	0	0	−1	—
14	0	0	0	0	70.69
15	0	0	0	1.5	100.00
16	0	0	1	−1	—
17	0	0	1	0	41.38
18	0	0	1	1.5	110.34
19	0	1	−1	−1	—
20	0	1	−1	0	51.50
21	0	1	−1	1.5	72.10
22	0	1	0	−1	—
23	0	1	0	0	63.79
24	0	1	0	1.5	120.69
25	0	1	1	−1	—
26	0	1	1	0	—
27	0	1	1	1.5	—
28	1	−1	−1	−1	18.88
29	1	−1	−1	0	200.86
30	1	−1	−1	1.5	137.34
31	1	−1	0	−1	8.58
32	1	−1	0	0	123.61
33	1	−1	0	1.5	140.77
34	1	−1	1	−1	17.24
35	1	−1	1	0	177.59
36	1	−1	1	1.5	153.45
37	1	0	−1	−1	17.24
38	1	0	−1	0	122.41
39	1	0	−1	1.5	131.03
40	1	0	0	−1	15.52
41	1	0	0	0	106.90
42	1	0	0	1.5	148.28
43	1	0	1	−1	20.69
44	1	0	1	0	148.28
45	1	0	1	1.5	158.62
46	1	1	−1	−1	17.17
47	1	1	−1	0	78.97
48	1	1	−1	1.5	101.29
49	1	1	0	−1	27.59
50	1	1	0	0	79.31
51	1	1	0	1.5	131.03
52	1	1	1	−1	—
53	1	1	1	0	—
54	1	1	1	1.5	—