Modification of Nanoclinoptilolite Zeolite with Hexadecyltrimethylammonium Surfactant as an Active Ingredient of Chromate-Selective Membrane Electrode

Table 7

Comparison of some potentiometric characteristics of the chromate ISE described in this paper with previously published reports.

Interference ions	Log 𝑘 values in the references		This paper
	[41]	[7]	SSM	FIM
CN^−	—	—	0.2	−3.2
Cl^−	−1.4	−2.9	2.5	−1.8
I^−	—	−1.8	1.6	−3
SO4^2−	−1.5	−4.0	−2.8	−2.9
C2O4^2−	−1.4	−2.1	−0.2	−3.2
CO3^2−	−1.6	−2.6	−1.3	−3.1
ClO4^−	−1.9	−1.8	−1.5	−3.0
NO3^−	−1.6	−2.4	−1.2	−1.9
Sal^a	—	−2.3	−1.5	−3.0
OAc^−	—	−3.2	1.8	−2.3
D.L. (p Chromate)	5.9	6	5.7
D.R. (p Chromate)	1–5.3	1–5.6	2–5.3
Response time (s)	13	20–25	5–10
Stability (day)	300	60	60
pH range^b	6.5–10.0	8.0–12.0	6.8–10.7
Slope (mV·decade^−1)	−29.0	−28.8	−29.4
Conditioning time (h)	—	—	2
Standard deviation	0.2	0.5	0.29

aSalicylate.
bThe pH range of the electrode response is independent of pH.