Intro to Chemistry (Physical Science)

Major Assignment


In Home Medical Kits: The $20 Urine Metal Test

In home testing has grown rapidly within the last decade for a variety of medical testing. These tests range from the urine pregnancy testing, blood glucose levels, blood A1C, HIV saliva, SG-10 urine perimeter strips and even alcohol testing for breast milk. These in-home tests are not just important for medical diagnosing, they are affordable and offer privacy. However, not all in-home test kits are perfect and the public could be unaware of their hazardous potentials.

Urine heavy metal testing is one of those tests, this test is offered online by various sellers on popular shopping sites. The test can test for Cadmium, Aluminum, Lead, Mercury, Zinc and NickelThese tests cost roughly the same, yet they offer no explanation for the reagent used. After digging a little further, the regent used turned out to be Dithizone (diphenylthiocarbazone). Naturally, being curious me, I purchased a few samples from one seller. My ultimate goal for this experiment is to determine whether or not compounds found in urine result as ‘false’ positive. Using the scientific method, I began to create a possible hypothesis that could set variables and constants for testing.


Determining if dithizone only tests positive for the range of Cadmium, Aluminum, Lead, Mercury, Zinc and Nickel.

General Hypothesis:

If Compounds are diluted with H2O, then are mixed with dithizone and allowed to sit for 10 minutes, then results will determine by using qualitative measurements that indicate positive or negative levels of heavy metals; Cadmium, Aluminum, Lead, Mercury, Zinc and Nickel.

If the compounds are not heavy metals, but colors change green then the results is negative. And if the compounds are not heavy metals, but colors change to any color other then green, then the results are false positive. And if the compounds are heavy metals, but colors change to any color other then green, then the results are false negative.

To simplify this statement, a function is used, using Swift 3.0 format and running on xCode. Where the compound is a constant that can be changed and the variable, whether the color changed green. The output is displayed through console.

//: Playground - noun: a place where people can play

import UIKit

let heavyMetalRange = ["Cadmium", "Aluminum", "Lead", "Mercury", "Zinc", "Nickel"]

let Compounds = "carbon" //Type element name.
var isItGreen = false //type true or false

func myHypothises() {
for scene in heavyMetalRange {
if scene.contains(Compounds){
print("\(Compounds) is in the heavy metal range.")
print("Test is negative. \nThis is a false negative.")
} else if (isItGreen==false){
print("Test is not green. \nThis is a true positive.")
break//end processes
else {
print("\(Compounds) is not in the heavy metal range.")
print("Test is negative. \nThis is a true positive")
} else if (isItGreen==false){
print("Test is not green. \nThis is a false positive.")
break//end processes
myHypothises() //run the function.


Screen Shot 2017-05-04 at 8.58.21 PM

The output when the constant (let) for the compound was changed to Carbon and the variable isItGreen was set to false.


Compounds are dissolved in an aqueous solution of 10mL (distilled water, H2O) and placed into a sterile vial. The following ratios were used (see table 1.) All tablets and capsules were crushed. No further ratios were determined due consistance of dosage strength.

Compound Strength Form Ratio of Solution
Calcium 500mg tablet (500mg/20mL)(X/1mL) = 25mg/mL
Zinc 100mg tablet (100mg/20mL)(X/ 1 mL) = 5mg/mL
Iron 29mg capsule (29mg/20mL)(X/1mL) = 1.45mg/mL
Vitamin B12 2mg/mL of Multivitamin B Solution (aq) (2mg/20mL)(X/1mL) = 0.1 mg/mL
Iodine (as Potassium Iodide) 0.5 mL/1 drop (aq) 0.5mL / drop
h20 (const) 10mL (l) 10mL
Ammonium Sulfide 0.5mL (aq) (0.5mL/20mL)(X/1mL) = 0.025 mg/mL

In a separate vial, all samples were given a ratio of 2 drops of H20, 2 drops of the compound and 8 drops of  dithizone, with 30 seconds of mixing by shaking of the vials by hand. The vials were set on vial racks for 10 minutes under light CFL light. The samples were read using strong CFL lighting.

Compound First Experiment Second Experiment
Calcium Positive Positive
Zinc Positive Negative
Iron Positive Negative
Vitamin B12 Negative Negative
Iodine (as Potassium Iodide) Positive Negative
h20 (const) Negative Negative
Ammonium Sulfide Negative Negative

A second experiment was performed with changing the ratio of solution and solutes, with 2 drops of H20, 1 drops of dithizone and 1 drop of compound. The following results were obtained; calcium tested false positive and Zinc tested false negative.

The third experiment was not performed to replicate the experiment due to resource limitations.

Data Analysis

False positive samples formed with Calcium, Iron, and Iodine. True positives resulted with Zinc and the formation of vapor also formed inside the vial for this sample. Samples are broken into three groups for color, pink-lander, yellow and clear. Additionally, note is taken with the vapor formed from the reaction of Calcium.

Compound at 10 mins, color Color @ 10 min Notes [email protected] 10 min Result
Calcium light purple. Pink clumps formed. Positive
Zinc clear light lavender small clumps formed. Some vapor in vial. Positive
Iron yellow pink large amount of clumps formed. Positive
Vitamin B12 yellow dark yellow small amount of clumps formed. Uknown
Iodine (as Potassium Iodide) clear light rose Small amount of clumps. Little disbursing of clumps. Positive
h20 (const) light yellow colorless Large amount of clumps formed. Unclear
Ammonium Sulfide clear yellow Little disbursing of clumps. Large amount of clumps formed. Unclear

The column titled ‘notes [email protected] 10 min’ (table above) represent vials after remixing by shaking the vials by hand. This test was read within 5 seconds.

A third  interpretation are the ratio used to obtain false positives or negatives, vice versa for true. The image below presents in a visual format how the first and second samples differed. 1 represents the sample being positive and 0 for negative. The overlapping samples are, Zinc, vitamin12, Iodine, Ammonium Sulfide.

Screen Shot 2017-05-04 at 10.33.14 PM


The experiment shows that there are compounds that trigger false positive and furthermore, false negatives. The false positives that strongly correlate is Calcium, and weaker strong positives include Iron, and Iodine. The experiment was unable to be replicated.


The urine heavy metal – in-home test proves limitations of accuracy and precision. The level of accuracy is dependent of high levels of variables that surround the compounds and the variables of different vitamins and nutrients within urine. Their claim of ‘positive’ being ‘green’ or ‘not green’ also pushes the boundaries of precision, when simple nutrients such as calcium trigger false positives for heavy metals.  Knowing this has prompted me to create a video of awareness for the public and create my own experimentation to support my claims, by using chemistry and the scientific method. I am confident of my findings and know the risks and potentials of this in-home test.