Frequently Asked Questions
Q: What Metals can our sensor analyze?
A: We currently have sensors for Lead (Pb), Copper (Cu), Uranium (U), Mercury (Hg), Zinc (Zn) and Cadmium (Cd). We plan to have Chromium (Cr) in 2013 and Arsenic (As) by early 2014.
Q: What are the detection ranges for each sensor?
A: Lead (Pb) 2-100 ppb
Copper (Cu) High – 0.3 – 3 ppm
Copper (Cu) Low – 40 – 200 ppb
Uranium (U) > 2 – 60 ppb
Mercury (Hg) – This is a qualitative sensor not a quantitative sensor. (Detects mercury above 2 ppb)
Zinc (Zn) – 1 – 15 ppm
Cadmium (Cd) High – 0.1 – 1.0 ppm
Q: Why does the Mercury (Hg) sensor produce a qualitative analysis rather than a quantitative answer?
A: The mercury sensor has a signal dependence to mercury which is sigmoidal instead of linear. Therefore, a 4 point calibration is required for accurate quantitative results which pose a challenge during on-site use. This sensor was not obtained by in vitro selection of DNA as is the case with our other sensors. All our future sensors will be in vitro selected and will be quantitative. We are also doing an in vitro selection to obtain a quantitative mercury sensor.
Q: Why do we have two copper sensors?
A: We have demand for two different levels. The U.S. EPA – maximum contaminant level (MCL) for copper in drinking water is 1.3 ppm and therefore the 0.3 – 3 ppm range sensor works well for this market. However, there is demand to test for lower levels as well (waste water/ NPDES market) which is why we have a copper sensor that analyzes levels between 40 – 200 ppb
Q: How are the sensors packaged?
A: Each specific sensor comes in quantities of 25 which can be used for Calibrations or Testings. Each sensor package includes everything needed to conduct a test including syringes, cuvettes etc. There are no additional costs other than the AND1000 Fluorimeter and sensors.
Q: What is the shelf life for each sensor?
A: The sensors shelf life is 1 year (12 months) for the sensors. The shelf life of the product is limited by the liquid buffer supplied with the sensor which can be improved with refrigeration. We are working on making a dry buffer which will increase shelf life to 15+months.
Q: What is the accuracy of our sensors?
A: Accuracy differs depending on the metal. Please see analytical data sheet of each sensor for details. For example for the lead sensor, the accuracy is ±15% for Pb in the 30-100 ppb range and ±20% for Pb for <30 ppb.
Q: How many times can a sensor be used?
A: Each sensor is designed for one test. After this you should dispose of the used sensor. We use disposable sensors to prevent cross contamination.
Q: Why do we use DNA / RNA Enzymes in our sensors?
A: Traditionally DNA/RNA was thought to be only genetic material. However in the 1980s, it was discovered that functional DNA/RNA that recognize a specific target can be obtained in the laboratory by a combinatorial process called in vitro selection. This process was used to find DNA/RNA that are specifically bind to lead, uranium, copper, other organic and biological toxins. ANDalyze converts such DNA to on-site sensors. The advantages of using DNA/RNA as sensors are:
Q: Do we use any bio hazardous materials?
A: No, all materials are environmentally friendly.
Q: How is each site calibrated?
A: Each site is calibrated by using one calibration unit and one sensor unit. Essentially a calibration is done by using a test sample and a spiked sample to calculate a percent recovery which is then stored as a factor for that site (or sample matrix). Calibration is required for each new site (when sample matrix changes) and when the temperature changes.
Q: Are the ANDalyze products or procedures validated by a water testing agency (EPA, FDA, NSF, etc)?
A: Yes, ANDalyze has received US EPA ETV Verification for our Lead sensor, confirming the reported accuracy against industry standard methods (ICP/MS). Please note that none of the methods are EPA certified for reporting requirements nor available in officially published Standard Methods, but they are true measurements and can be used to determine concentration levels.
Q: What do I need to keep in mind when comparing ANDalyze results to
laboratory testing techniques such as Atomic Absorption (AA) and Inductively
Coupled Plasma (ICP)?
A: Once the ANDalyze test is completed, the same sample (filtered and diluted as required for ANDalze tests) can be sent for ICP or AA; however it should be preserved by adding nitric acid to a final pH < 2.