滴下ビスマス電極を使用した飲料水中のカドミウムと鉛の測定

人体へのカドミウムの有毒影響を軽減し、また鉛の神経毒性影響を制限するために、世界保健機関の「飲料水の品質に関するガイドライン」における仮の指針値は、カドミウムについては最大濃度を3μg/L、鉛については10μg/Lに設定されています。完全に水銀フリーの滴下ビスマス電極は、ボルタンメトリー分析を非有毒な重金属検出装置としました。この環境にやさしい電極を用いて飲料水中のカドミウムと鉛を同時定量が可能です。

Drinking water, mineral water

The water sample and the supporting electrolyte are pipetted into the measuring vessel. The simultaneous determination of cadmium and lead is carried out with a 884 Professional VA using the parameters specified in Table 1. The concentration of both elements is determined by two additions of a cadmium and lead standard addition solution.

The Bi drop electrode is electrochemically activated prior to the first determination of cadmium and lead.

Figure 1. 884 Professional VA fully automated for VA

**Table 1.** Parameters
Parameter	Setting
Mode	DP – Differential Pulse
Deposition potential	-1.1 V
Deposition time	60 s
Start potential	-1 V
End potential	-0.35 V
Peak potential Cd	-0.7 V
Peak potential Pb	-0.5 V

Working electrode: Bi drop
Reference electrode: Ag/AgCl/KCl (3 mol/L)
Auxiliary electrode: Glassy carbon rod

The method is suitable for the determination of cadmium and lead in water samples in concentrations up to 15 µg/L. The limit of detection of the method is 0.1 µg/L for approximately cadmium and 0.5 µg/L for lead.

Figure 2. Determination of cadmium and lead in tap water spiked with β(Cd) = 2 µg/L and β(Pb) = 2 µg/L

**Table 2.** Results
Sample	Cd (µg/L)	Pb (µg/L)
Tap water spiked with β(Cd) = 2 µg/L and β(Pb) = 2 µg/L	2.0	2.3

Application Bulletin 438: Determination of cadmium and lead in water samples by anodic stripping voltammetry with a Bi drop electrode

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