in further embodiments chromatography paper can be used suitable paper includes filter and chromatography paper sold under the brand name whatman u2122 available from sigma aldrich inc in further embodiments a detection strip is obtained by depositing a drop of a silver nitrate solution on a piece of chromatography paper and allowing the drop to dry as shown in fig1 a gypsum sample is weighed and placed in a heat resistant container as shown in fig2 suitable containers include heat resistant vials beakers flasks bottles and test tubes a heat resistant container can be made from heat resistant glass ceramic metal or metal alloy the detection strip is deposited inside of a carrier lid the carrier lid can be made from heat resistant glass or any other heat resistant material the carrier lid can be in a bell like shape as shown in fig3 and designed such that it holds the detection strip in place as shown in fig3 and prevents it from slipping out from the lid after the lid is placed over the container with the gypsum sample as shown in fig4 in further embodiments the carrier lid can be equipped with at least one set of means selected from the following pins clips rings semi rings an insert or a gasket for securing the detection strip inside of the carrier lid the carrier lid can be designed with a slot inside the lid such that the detection strip is secured in the slot in further.