Table 5.

Regression coefficient of the coded factors and analysis of variance for the response surface models of average peak area and S/N for the optimization of sheath liquid and spray chamber parameters.

Term	Peak area-BNP		Peak area-BOH		S/N-BNP		S/N-BOH
	Coefficient	Prob > F	Coefficient	Prob > F	Coefficient	Prob > F	Coefficient	Prob > F
Sheath liquid parameters
Intercept (b0	50157		261600		115.08		548.27
F1: %MeOH	7398	0.45	111300	0.00020	39.36	0.0097	231.88	0.0018
F2: pH	9393	0.34	3710	0.85	−1.51	0.91	−14.65	0.80
F3: [NH4OAc]	−38087	0.0034	−51430	0.029	−24.65	0.092	108.84	0.094
F1 F2	15646	0.23	1789	0.94	10.81	0.52	37.14	0.62
F1 F3	2891	0.82	−28350	0.28	2.94	0.86	107.51	0.17
F2 F3	−15098	0.24	−2155	0.93	−5.14	0.76	3.74	0.96
F12	−17514	0.082	−42167	0.045	−33.17	0.020	−132.74	0.032
F22	−3401	0.71	20435	0.29	21.29	0.11	95.67	0.10
F32	23716	0.050	13276	0.55	10.81	0.46	−35.48	0.58
R2		0.72		0.83		0.72		0.77
Adjusted R2		0.47		0.68		0.48		0.57
Predicted R2		−0.90		−0.13		−0.96		−0.66
P-lack of fit		<0.0010		0.010		0.024		0.0035
Spray chamber parameters
Intercept (b0)	90906		3.1990 × 105		25.12		75.2
F1: DGF	819.32	0.91	−4209.4	0.85	1.41	0.14	0.310	0.89
F2: DGT	10108	0.17	39253	0.10	−0.810	0.38	−2.60	0.29
F1 F2					1.33	0.31	8.88	0.028
F12					1.61	0.12	7.14	0.022
F22					−0.240	0.80	−1.64	0.52
R2		0.18		0.25		0.54		0.73
Adjusted R2		0.013		0.095		0.21		0.53
Predicted R2		−0.19		−0.26		0.076		0.017
P-lack of fit		0.92		0.72		0.95		0.56