EM Quant® Calcium Test
Test strips and reagents for the detection and
semi-quantitative determination of calcium ions
The calcium test is ideal for performing rapid semi-quantitative determinations
of calcium in aqueous media. It is also useful in quality control as a
means of measuring concentrations of calcium compounds. These may be incorporated
into animal feeds and fertilizers, or may be used as cleaners or polishes,
or whiteners in enamels, glassware and porcelain. Calcium also has an
important physiological role, e.g. in human bone tissue, a fact reflected
by an EEC recommendation that drinking water should contain 100mg/liter
In wine, calcium concentrates must be kept below 40-50mg/liter to avoid
calcium tartrate deposits.
The EM Quant® Calcium Test can also be used as a general
test for heavy metals, provided that the masking described under "Influence
of cations" is omitted. A blue-violet color on the reaction zone
indicates 10mg/liter of cadmium, gray indicates 10mg/liter of copper and
green indicates 25mg/liter of lead.
Principle of the Method
The calcium detection is based on the formation
of a complex between calcium ions and glyoxal-bis-2-hydroxyanil in the
presence of hydrogen peroxide.
0 - 25 - 50 - 100 - 250mg/l (ppm) Ca+
- Rinse the measuring vessel several times with some of the sample
and fill to the 5ml mark.
- Immerse the test strip in the solution for 1
second, remove, shake gently and set aside with the reaction zone
- Add 1 level measuring spoon of reagent 1 to
the sample solution and swirl to dissolve.
- Add 10 drops of reagent 2 (sodium hydroxide
solution) and swirl.
- Immerse the reaction zone in this solution
for 45 seconds.
- Remove the test strip and wipe off excess
liquid by stroking the edge of the test strip against the rim of the
vessel, and compare the reaction zone with the color scale.
Keep reagent 2 (32% sodium hydroxide solution)
away from the skin. In the event of contact, rinse well immediately
with plenty of water. Seek immediate medical attention if substance
enters the eye.
Influence of Anions
The determination is not disturbed by less than:
Cl-, ClO, ClO, CN- , CrO, [Fe(CN)6]4-
, l- , IO Mo7O , N, NO , NO OCN-
The determination is not disturbed by less than 1000mg/l Br-,
BrO3-, Cl-, ClO, ClO3-,
CN- , CrO42-, [Fe(CN)6]4-
, I- , IO3-, Mo7O246-,
N3-, NO2-, NO3-,
OCN-, PO4-3, SCN-, S2O52-,
WO42-, acetate, ascorbate, succinate or tartrate.
A brown discoloration is caused by more than 200mg/l [Fe(CN)6]3-
or MnO4-. Detection is prevented by more than 10mg/l
Influence of Cations
The determination is not disturbed by less than 1000mg/l Al3+,
As3+, Ba2+, Bi3+, Mg2+, NH4+,
Pb2+, Rb+, Sb3+, Sr2+ or VO2+.
Interfering discolorations are caused by more
400mg/l Ag+ (black)
300mg/l Au3+ (gray-green)
10mg/l Cd2+ (blue-violet)
50mg/l Co2+ (dark violet)
350mg/l Cr3+ (light green)
10mg/l Cu2+ (gray)
100mg/l Fe2+ (green)
100mg/l Fe3+ (brown)
100mg/l Hg+ (green-brown)
100mg/l Hg2+ (gray)
50mg/l Mn2+ (gray-yellow)
50mg/l Ni2+ (brown)
25mg/l Pb2+ (green)
200mg/l Sn2+ (pink)
25mg/l Zn2+ (brown)
More than 10 mg/l Ce3+/4+ , Ti4+
or Zr+ prevents the detection of less than 25 ppm Ca2+.
Elimination of Interference
Interfering anions can be removed by using Amberlite® IRA-400 ion
exchanger, about 2 mmol of anions being absorbed per g of ion exchanger.
Allow 20ml of the weakly acidic to neutral sample solution to run slowly
(1 drop/second) through a glass column (5-10mm in diameter) filled with
2g of Amberlite® IRA-400 strong-base ion exchanger. The solution must
not contain more than 2000mg/l (ppm) of the interfering anion. Then test
for Ca2+ as described in the directions.
Interference by cations can be eliminated by adjusting 5ml of test solution
to approximately pH 8 with sodium acetate and then adding a spatula-tip
of potassium cyanide. The interference caused by more than 50mg/l Tl+
(brown) is prevented by adding potassium iodide.
19778 Calcium standard solution, 500ml.
10034 EM Quant® Test strips and
Calcium Test for 100 determinations