{"id":4349,"date":"2019-01-24T22:07:39","date_gmt":"2019-01-25T06:07:39","guid":{"rendered":""},"modified":"2025-06-17T08:43:22","modified_gmt":"2025-06-17T15:43:22","slug":"4349","status":"publish","type":"post","link":"https:\/\/www.vernier.com\/til\/4349","title":{"rendered":"Go Direct Calcium Ion-Selective Electrode Troubleshooting and FAQs"},"content":{"rendered":"<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-vertically-aligned-center is-layout-flow wp-block-column-is-layout-flow\">\n<h3 class=\"wp-block-heading\"><a href=\"\/product\/go-direct-calcium-ion-selective-electrode\/\">Go Direct<sup>&reg;<\/sup> Calcium Ion-Selective Electrode<\/a> (<nobr>GDX-CA<\/nobr>)<\/h3>\n<div style=\"height:20px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n<p><a href=\"\/manuals\/GDX-CA\">Specifications and User Guide<\/a><\/p>\n<\/div>\n<div class=\"wp-block-column is-vertically-aligned-center is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"https:\/\/www.vernier.com\/wp-content\/uploads\/2019\/11\/product.gdx-ca._hero.001-scaled.jpg\" alt=\"\"\/><\/figure>\n<\/div>\n<\/div>\n<h3 class=\"wp-block-heading\">Troubleshooting<\/h3>\n<p><strong>General: <\/strong>Press the power button on the sensor to turn it on. Connect your sensor as described in the <a href=\"https:\/\/www.vernier.com\/til\/get-started\/go-direct\">Getting Started instructions for your device<\/a>. (The green LED will flash to indicate the sensor is connected.)<\/p>\n<ul class=\"wp-block-list\">\n<li><strong>Primary Test:<\/strong> Check the readings in the standards. The high should be around 1000 mg\/L. The low should be around 10 mg\/L.<\/li>\n<\/ul>\n<p class=\"has-text-align-center has-very-light-gray-background-color has-background\">See also, <a href=\"\/til\/665\/\">General tips for using Ion Selective Electrodes (ISE).<\/a><\/p>\n<div style=\"height:20px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n<h3 class=\"wp-block-heading\">Additional Troubleshooting<\/h3>\n<ul class=\"wp-block-list\">\n<li><a href=\"\/til\/4011\/\">How do I calibrate my sensor?<\/a><\/li>\n<li><a href=\"\/til\/1060\/\">Do any of your sensors require special storage?<\/a><\/li>\n<li><a href=\"\/til\/759\/\">Do you sell ISE Standards?<\/a><\/li>\n<li><a href=\"\/til\/665\/\">General tips for using Ion Selective Electrodes (ISE).<\/a><\/li>\n<li><a href=\"\/til\/3389\/\">How do I sterilize an Ion-Selective Electrode?<\/a><\/li>\n<li><a href=\"\/til\/15786\/\">Go Direct sensor does not connect to LabQuest 2 via Bluetooth.<\/a><\/li>\n<li><a href=\"\/til\/15056\/\">How do I replace the battery in a Go Direct Wand-Style Sensor?<\/a><\/li>\n<li><a href=\"\/til\/6827\/\">Troubleshooting Bluetooth Connections with Go Direct Sensors<\/a><\/li>\n<li><a href=\"\/til\/12943\/\">What can I do if a Go Direct sensor's Bluetooth LED flashes red and green when I try to connect to it and the connection fails?<\/a><\/li>\n<li><a href=\"\/til\/3857\/\">Will my device work with Go Direct Sensors via Bluetooth?<\/a><\/li>\n<li><a href=\"\/til\/3085\/\">How do I know if my LabQuest will work with Go Direct Sensors and Go Wireless devices?<\/a><\/li>\n<\/ul>\n<div style=\"height:20px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n<h3 class=\"wp-block-heading\">Specifications<\/h3>\n<ul class=\"wp-block-list\">\n<li>Range <br \/>\u26ac mV: \u00b11000 mV<br \/>\u26ac concentration: 1 to 40,000 mg\/L (or ppm)<\/li>\n<li>Accuracy: \u00b110% of full scale (calibrated 10 to 1000 mg\/L)<\/li>\n<li>Reproducibility (precision): \u00b130mV<\/li>\n<li>Interfering ions: Pb<sup>2+<\/sup>, Hg<sup>2+<\/sup>, Si<sup>2+<\/sup>, Fe<sup>2+<\/sup>, Cu<sup>2+<\/sup>, Ni<sup>2+<\/sup>, NH<sub>3<\/sub>, Na<sup>+<\/sup>, Li<sup>+<\/sup>, Tris<sup>+<\/sup>, K<sup>+<\/sup>, Ba<sup>2+<\/sup>, Zn<sup>2+<\/sup>, Mg<sup>2+<\/sup><\/li>\n<li>pH range: 2\u20138 (no pH compensation)<\/li>\n<li>Temperature range: 0\u201340\u00b0C (no temperature compensation)<\/li>\n<li>Electrode slope: 26 \u00b1 2 mV\/decade at 25\u00b0C<\/li>\n<li>Electrode resistance: 100 M\u03a9<\/li>\n<li>Minimum sample size: must be submerged 2.8 cm (1.1 in)<\/li>\n<li>Standard solution voltages (typical)<br \/>\u26ac High (1000 mg\/L): 80 mV<br \/>\u26ac Low (10 mg\/L): 30 mV<\/li>\n<li>Dimensions<br \/>\u26ac ISEA amplifier: 8.5 cm height x 3 cm wide x 1.75 cm depth<br \/>\u26ac Ca electrode: 15.5 cm length, 12 mm OD<\/li>\n<li>Connections:<br \/>\u26ac Wireless: Bluetooth<sup>\u00ae<\/sup> v4.2 (wireless range 30 m unobstructed) <br \/>\u26ac Wired: USB 2.0 full speed<\/li>\n<li>Battery: <a href=\"http:\/\/www.vernier.com\/gdx-bat-300\">300 mA Li-Poly<\/a><br \/>\u26ac Battery Life (single, full charge): ~24 hours continuous data collection<br \/>\u26ac Battery Life (lifetime): 2 \u2013 5 years (typical)<\/li>\n<\/ul>\n<div style=\"height:20px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n<h3 class=\"wp-block-heading\">Calibration<\/h3>\n<p>Calibrate? Yes. Conduct a two-point calibration using the standard solutions that are shipped with the sensor. For more information, see <a href=\"\/til\/4011\/\">How do I calibrate my sensor?<\/a><\/p>\n<ol class=\"wp-block-list\">\n<li>Soak the ISE in the High Standard for 30 minutes<br \/>\u26ac The ISE should not rest on the bottom of the container.<br \/>\u26ac The small white reference contacts near the tip of the electrode should be immersed.<br \/>\u26ac Make sure no air bubbles are trapped below the ISE.<\/li>\n<li>Connect the sensor to the software and start a two point calibration.<\/li>\n<li><strong>First point:<\/strong> The sensor should still be soaking in the High Standard. <br \/>\u26ac Enter the concentration value of the High Standard. <br \/>\u26ac Hold the ISE still and wait for the relative stability reading to stabilize.<br \/>\u26ac Keep the first reading.<\/li>\n<li>Remove the ISE from the High Standard, rinse well with distilled water from a wash bottle, and gently blot dry with a paper towel or lab wipe. <\/li>\n<li><strong>Second point: <\/strong>Place the electrode into the Low Standard. <br \/>\u26ac Enter the concentration value of the Low Standard.<br \/>\u26ac Hold the ISE still and wait for the relative stability reading to stabilize.<br \/>\u26ac Keep the second reading.<\/li>\n<\/ol>\n<p class=\"has-text-align-left has-very-light-gray-background-color has-background\">Most ISE measurements are done in water that is moving, so stirring the solution during calibration is important. For best results, suspend the ISE in a beaker containing the standard solution and use a stir station with magnetic stir bar to stir the solution as you calibrate the sensor. (<a href=\"https:\/\/youtu.be\/9Yfq6drXiYU\">Calibration video<\/a>)<\/p>\n<div style=\"height:20px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n<h3 class=\"wp-block-heading\">Battery Troubleshooting<\/h3>\n<ol class=\"wp-block-list\">\n<li><span style=\"font-weight: 400;\">If the sensor can be turned on when connected by USB but not when disconnected from USB, the battery either needs charging or has reached its end of life and can no longer hold a charge. <\/span><br \/>\u26ac <span style=\"font-weight: 400;\">First, try charging the sensor for several hours. <\/span><\/li>\n<li><span style=\"font-weight: 400;\">If the sensor still won\u2019t turn on when disconnected from USB, try swapping the battery with a working sensor to see if the problem follows the battery or stays with the sensor.<\/span><br \/>\u26ac If the problem stays with the sensor, the battery is probably not the issue.<br \/>\u26ac If the problem follows the battery, <span style=\"font-weight: 400;\">the battery has likely reached its end of life.<\/span><\/li>\n<li><span style=\"font-weight: 400;\">If you intend to use this sensor wirelessly, its battery will need replacing<\/span>.<br \/><span style=\"font-weight: 400;\"><a href=\"\/product\/go-direct-300-mah-replacement-battery\/\">Go Direct&reg; 300 mAh Replacement Battery<\/a> (<nobr>GDX-BAT-300<\/nobr>)<\/span><\/li>\n<li>See <a href=\"\/til\/15056\/\">How do I replace the battery in a Go Direct Wand-Style Sensor?<\/a> for more information (including a <a href=\"https:\/\/youtu.be\/BRLhaOUjmaI\">video<\/a>).<\/li>\n<\/ol>\n<div style=\"height:20px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n<p class=\"has-text-align-center has-very-light-gray-background-color has-background\"><span style=\"font-weight: 400;\"><strong>Rechargeable batteries are covered by a one-year warranty.<\/strong><\/span><br \/>Batteries <span style=\"font-weight: 400;\">should last two to five years in typical use. <\/span><\/p>\n<div style=\"height:20px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<h3 class=\"wp-block-heading\">Related Products<\/h3>\n<ul class=\"wp-block-list\">\n<li><a href=\"\/product\/micro-usb-to-usb-c-cable\/\">Micro USB to USB-C Cable<\/a> (<nobr>CB-USB-C-MICRO<\/nobr>)<\/li>\n<li><a href=\"\/product\/go-direct-charge-station\/\">Go Direct<sup>&reg;<\/sup> Charge Station<\/a> (<nobr>GDX-CRG<\/nobr>)<\/li>\n<li><a href=\"\/product\/electrode-support\/\">Electrode Support<\/a> (<nobr>ESUP<\/nobr>)<\/li>\n<li><a href=\"\/product\/stir-station\/\">Stir Station<\/a> (<nobr>STIR<\/nobr>)<\/li>\n<li><a href=\"\/product\/go-direct-sensor-clamp\/\">Go Direct&reg; Sensor Clamp<\/a> (<nobr>GDX-CLAMP<\/nobr>)<\/li>\n<li><a href=\"\/product\/go-direct-ammonium-ion-selective-electrode\/\">Go Direct<sup>&reg;<\/sup> Ammonium Ion-Selective Electrode<\/a> (<nobr>GDX-NH4<\/nobr>)<\/li>\n<li><a href=\"\/product\/go-direct-chloride-ion-selective-electrode\/\">Go Direct<sup>&reg;<\/sup> Chloride Ion-Selective Electrode<\/a> (<nobr>GDX-CL<\/nobr>)<\/li>\n<li><a href=\"\/product\/go-direct-nitrate-ion-selective-electrode\/\">Go Direct<sup>&reg;<\/sup> Nitrate Ion-Selective Electrode<\/a> (<nobr>GDX-NO3<\/nobr>)<\/li>\n<li><a href=\"\/product\/go-direct-potassium-ion-selective-electrode\/\">Go Direct<sup>&reg;<\/sup> Potassium Ion-Selective Electrode<\/a> (<nobr>GDX-K<\/nobr>)<\/li>\n<li><a href=\"\/product\/calcium-ion-selective-electrode\/\">Calcium Ion-Selective Electrode<\/a> (<nobr>CA-BTA<\/nobr>)<\/li>\n<\/ul>\n<\/div>\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<h3 class=\"wp-block-heading\">Replacement Parts<\/h3>\n<ul class=\"wp-block-list\">\n<li><a href=\"\/product\/go-direct-300-mah-replacement-battery\/\">Go Direct&reg; 300 mAh Replacement Battery<\/a> (<nobr>GDX-BAT-300<\/nobr>)<\/li>\n<li><a href=\"\/product\/micro-usb-cable\/\">Micro USB Cable<\/a> (<nobr>CB-USB-MICRO<\/nobr>)<\/li>\n<li><a href=\"\/product\/calcium-replacement-module\/\">Calcium Replacement Module<\/a> (<nobr>CA-MOD<\/nobr>)<\/li>\n<li>10&nbsp;mg\/L <a href=\"\/product\/standard-ca-ise-solution\/\">Standard Ca ISE Solution<\/a> (<nobr>CA-LST<\/nobr>)<\/li>\n<li>1000&nbsp;mg\/L <a href=\"\/product\/standard-ca-ise-solution\/\">Standard Ca ISE Solution<\/a> (<nobr>CA-HST<\/nobr>)<\/li>\n<li><a href=\"\/product\/electrode-storage-bottles\/\">Electrode Storage Bottles<\/a> (<nobr>BTL-ES<\/nobr>)<\/li>\n<li><a href=\"\/product\/go-direct-ion-selective-electrode-amplifier\/\">Go Direct<sup>&reg;<\/sup> Ion-Selective Electrode Amplifier<\/a> (<nobr>GDX-ISEA<\/nobr>)<\/li>\n<li><a href=\"\/product\/go-direct-calcium-ion-selective-electrode-bnc\/\">Go Direct&reg; Calcium Ion-Selective Electrode BNC<\/a> (<nobr>GDX-CA-BNC<\/nobr>)<\/li>\n<\/ul>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Specifications and User Guide Troubleshooting General: Press the power button on the sensor to turn it on. Connect your sensor as described in the Getting&#8230;<\/p>\n","protected":false},"author":11015,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[],"tags":[1889,7249,7242,6519,1883,720],"class_list":["post-4349","post","type-post","status-publish","format-standard","hentry","tag-caise","tag-gdxca","tag-gdxise","tag-gdxmain","tag-isemain","tag-maintil"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/posts\/4349","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\/11015"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/comments?post=4349"}],"version-history":[{"count":0,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/posts\/4349\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/media?parent=4349"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/categories?post=4349"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vernier.com\/til\/wp-json\/wp\/v2\/tags?post=4349"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}