Table 5. Comparison of Some Potentiometric Sensors Used for the Determination of Nicotine.

sensing material	sensor Type	slope (mV/decade)	lower limit of linear range, M	detection limit, M	pH range	ref.
nicotinium tetraphenyl borate	liquid membrane electrode	55	4.0 × 10–5	1.7 × 10–5	4.5–7	(53)
nicotinium nitrobarbaturate		54	1.0 × 10–5	1.1 × 10–5	3.5–7
nicotinium flavinate		50	5.0 × 10–5	3.0 × 10–5	3.5–7
nicotinium reineckate		55	5.0 × 10–5	2.5 × 10–5	3.5–7
nicotinium picrolonate		52	1.0 × 10–3	3.0 × 10–4	3.7–6.7
nicotine hydrogen tetra (m-chlorophenyl) borate	liquid membrane electrode	58	1.0 × 10–5	1.0 × 10–5	4.0–7.0	(54)
nicotinium tetraphenyl borate	paper-based analytical devices	55.2 ± 0.3	1.0 × 10–5	6.0 × 10–6	3.5–6.5	this work
nicotinium nitrobarbaturate		51.2 ± 0.6	1.0 × 10–5	8.0 × 10–6