{"id":3922,"date":"2017-06-01T23:39:08","date_gmt":"2017-06-02T06:39:08","guid":{"rendered":""},"modified":"2021-04-16T12:26:38","modified_gmt":"2021-04-16T19:26:38","slug":"3922","status":"publish","type":"post","link":"https:\/\/www.vernier.com\/til\/3922","title":{"rendered":"Does Vernier offer a sensor to test for lead in water?"},"content":{"rendered":"

There are a few options for testing lead in water that can be used with Vernier products. Please pay close attention to the chemicals required and use appropriate caution.<\/p>\n

Spectrophotometric<\/strong><\/p>\n

One option for testing lead uses a colorimetric method based on a lead-dithizone complex. In a weak alkaline solution, dithizone can form a stable complex with lead in a 2:1 ratio . This complex has a maximum absorbance at 520 nm. This option uses Chloroform and Potassium Cyanide. The Lead Reagent Set (Dithizone Method) can be purchased from Hach (Product Number 2243100).<\/p>\n

The following spectrophotometers can be used. A Vernier Colorimeter can’t be used with this test.<\/p>\n

Go Direct®<\/sup> SpectroVis®<\/sup> Plus Spectrophotometer<\/a> (GDX-SVISPL<\/nobr>) *Glass cuvettes are required.
Vernier Spectrometer<\/a> (V-SPEC<\/nobr>)
Vernier UV-VIS Spectrophotometer<\/a> (VSP-UV<\/nobr>)
Vernier Fluorescence\/UV-VIS Spectrophotometer<\/a> (VSP-FUV<\/nobr>)<\/p>\n

LaMotte also has a Lead Screening Test Kit for Drinking Water (Order Code 5-0140) that detects lead levels above 15 ppb which is the EPA action level.<\/p>\n

Electrochemical<\/strong><\/p>\n

The Go Direct®<\/sup> Cyclic Voltammetry System<\/a> (GDX-CVS<\/nobr>) can measure lead in water. However, the only fairly reliable way to do it uses mercury. This can be a problem for some schools, so we haven’t written a formal experiment around it. It’s also important to note that the GDX-CVS doesn\u2019t do DPV (differential pulse voltammetry), but it can perform ASV (anodic stripping voltammetry) by performing two experiments in sequence.<\/p>\n

After preparing the SPE with a thin layer of mercury (by bulk electrolysis), ASV is just:<\/p>\n

    \n
  1. A bulk electrolysis while stirring solution, such that lead ion amalgamates with the Hg layer by a reduction process (Pb2+<\/sup> + 2e \u2192 Pb (amalgam)) \u2013 known as the \u201cconcentration\u201d phase; then<\/li>\n
  2. A linear sweep voltammetry experiment (i.e., cyclic voltammetry with n = 1 segment) to oxidize Pb (amalgam) to Pb2+<\/sup> (i.e. sweep from \u2013 potential to +potential), which is what is measured and compared to a calibration curve to find unknown Pb2+<\/sup> concentration.<\/li>\n<\/ol>\n

    So, if you aren\u2019t scared of using mercury acetate to form a thin film of mercury on the SPE, then you should look at Pine’s lab exercise and adapt it to using the GDX-CVS.  You can review that lab here<\/a>.<\/p>\n

    Ion-Selective Electrode<\/strong><\/p>\n

    Vernier does not offer a lead ISE.
    A Lead Ion-Selective Electrode with a BNC connector is commercially available but can’t be used with our     Electrode Amplifier<\/a> (    EA-BTA<\/nobr>) or the Go Direct®<\/sup> Electrode Amplifier<\/a> (GDX-EA<\/nobr>). The amplifier can accommodate electrode outputs from -80 mV to 300 mV. Typically Lead ISEs fall outside of this range (-100 to -240 mV). See Can I use my third-party ISE with my Vernier equipment?<\/a><\/p>","protected":false},"excerpt":{"rendered":"

    There are a few options for testing lead in water that can be used with Vernier products. Please pay close attention to the chemicals required…<\/p>\n","protected":false},"author":41204,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[],"tags":[7493,2307,3284,6592,2163],"class_list":["post-3922","post","type-post","status-publish","format-standard","hentry","tag-cvs","tag-electrochemical","tag-lead","tag-pb","tag-spectrometer"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/posts\/3922","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/users\/41204"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/comments?post=3922"}],"version-history":[{"count":0,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/posts\/3922\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/media?parent=3922"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/categories?post=3922"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/tags?post=3922"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}