Table 1.

Typical operating conditions of Pb sensors based on Hg-film electrodes and SAMMS-based electrodes.

Parameter	Condition
Flow system	FIA/ASV at Hg-film electrode
Sample preparation	a) Pb-spiked samples containing 10–50 vol% urine, 10 vol% bood, or 50 vol% saliva; b) 10-min incubation; c) acidified to 1 M HCl; and d) filtered through 5,000 NMWL cut-off ultrafilters
Sample volume	60 μL per measurement
Carrier	5 ppm Hg/0.5 M HCl
Flow rate	1 μL/sec
Preconcentration	–1.0 V, 110 sec
Detection by SWV	Scan from –0.75 V to –0.45 V
Electrode precondition	0.6 V, 90 sec in carrier
Batch measurements	SAMMS-based electrodes
SAMMS	5–10 wt% of SH-, AcPhos-, or IDAA-SAMMS
Conductive matrix	Cabon paste, graphite ink, or carbon nanotube paste
Samples	Pb in DI water, groundwater, or samples contained 25% rat urine
Sample volume	8 mL waters or 0.5 mL of urine samples
Preconcentration	2–5 min in stirred solutions at open circuit
Electrolysis	–0.8 V to –1 V for 60 sec in 0.3–0.5 M HNO3 or HCl
Detection by SWV	Scan from –0.7 V to –0.35 V
Electrode cleaning	Often not required

Abbreviations: AcPhos, acetamide phosphonic acid; DI, deionized; IDAA, iminodiacetic acid; SWV, square-wave stripping voltammetry.