ICP analyzers can analyze multiple elements simultaneously in a single measurement. Therefore, they are useful for controlling trace elements in foods and drugs in addition to electronic materials and water quality. FUJIFILM Wako offers specifications of reagents for various measuring methods, such as atomic absorption spectrometry (AAS) and ICP optical emission spectroscopy (ICP-OES). In addition to single element standard solutions, multi-element mixture standard solutions suitable for various requirements are also available.

Furthermore, FUJIFILM Wako has a search system that allows you to easily search for these.

We believe that many researchers are preparing standard solutions by mixing elements to be measured with commercially available single element or multi-element mixture standard solutions.

Wait a minute! Can the "Standard" prepared now really become the Analytical Standard?

Different factors described below may cause element concentration to shift during preparation.

Contamination by water and acids used for dilution	: Use of a reagent without element guarantee
Contamination caused by laboratory instruments	: Elution of a resin stabilizer contained in a container and elution of glass components
Errors during experimental work	: Error in dilution calculation, mix-up of reagents, error in reagent injection volume
Contamination caused by experimental environment	: Contamination risk in a clean draft
Decreased concentration due to precipitation	: Precipitation due to acidity or alkalinity, compatibility of element ions with specific acids
Interfering ions	: Isobaric ions, adduct ions, and polyatomic ion interference, etc.

As shown above, there are many precautions when preparing standard solutions of multiple elements, and it is generally said that combinations in Table 1 are not compatible with regard to a decrease in element concentration due to precipitation. One of famous examples is precipitation observed when silver standard solutions are mixed with the other hydrochloric acid-based solutions.

Table 1. List of precipitation in solution by combination of ions

+: No formation of a precipitate,　-: Formation of a precipitate

• The above list is not applicable depending on the element concentration in a container.

Main element precipitation and color

Halides	CaF2(white), AgCl(white), PbCl2(white), AgBr(light yellow), AgI(yellow)
Sulfate	CaSO4(white), SrSO4(white), BaSO4(white), PbSO4(white)
Carbonate	CaCO3(white), MgCO3(white), BaCO3(white)
Hydroxide	Al(OH)3(white), Fe(OH)2(light green), Fe(OH)3(red brown), Cu(OH)2(bluish white), Cr(OH)3(regrayish green), Ni(OH)2(green)
Oxide	Al2O3(white), ZnO(white), MnO2(black), Ag2O(dark brown), FeO(black), Fe2O3(red brown), Fe3O4(black), CuO(black), Cu2O(red brown)
Chromate	BaCrO4(yellow), PbCrO4(yellow), Ag2CrO4(red brown)
Sulfide	CuS(black), Ag2O(black), PbS(black), ZnS(white), MnS(pink), SnS(brown), CdS(yellow)

FUJIFILM Wako has many know-how on the liquidity of standard solutions as well as solid technology cultivated as a reference material producer (ISO 17034) and delivers highly reliable standard solutions in element concentration.

Reference: Comparison List of Compositions for 3 Specifications of Element Standard Solution

●Liquid color coding

Acid	Red background
Neutral	White background
Alkali	Blue background

Nitric acid: Black characters
Sulfuric acid: Blue characters
Hydrochloric acid: Green characters