Reagent synthesis and testing assays to detect and quantify manganese (II)
View Patent ↗The present disclosure relates to methods of detecting manganese in a solution using resacetophenone oxime by spectrophotometric analysis wherein the resacetophenone oxime produces colorimetric responses to indicate the presence of manganese. The resacetophenone oxime is not only stable in solution, but it also may be inserted into a hydrocolloid gel to facilitate a “spot test” for the detection of manganese, resulting in a long shelf life. These manganese testing methods disclosed herein may be used at the pre-disinfection process at water treatment facilities. The disclosed methods of manganese testing may be combined with an ammoniacal buffer reagent that may be used by water processing facilities, prior to final disinfection, to augment existing manganese (II) efforts of removal. A secondary flocculation with this buffer will scavenge additional manganese (II), that can then be removed by sedimentation or filtration.
1. A method for testing for the presence of manganese in a sample solution, comprising the steps of:
preparing at least one positive control, wherein the positive control contains manganese;
preparing a negative control containing no manganese;
adding resacetophenone oxime to the at least one positive control, negative control and the sample solution, wherein the resacetophenone oxime is contained within a hydrocolloid gel, wherein the hydrocolloid gel is configured to at least partially dissolve upon adding the resacetophenone oxime to the at least one positive control, negative control and the sample solution;
incubating the at least one positive control, negative control and the sample solution; and
measuring the at least one positive control, negative control and the sample solution for a colorimetric reaction, wherein a colorimetric reaction indicates the presence of manganese.
2. The method of claim 1 , wherein the step of preparing at least one positive control comprises preparing a series of two or more positive controls, ranging in manganese concentration from about 10 to 500 micrograms.
3. The method of claim 2 , wherein the positive controls comprise manganese concentrations of about 10, 50, 100, 250 and 500 micrograms.
4. The method of claim 1 , wherein the resacetophenone oxime is at a concentration of 0.2% w/v in 10% v/v ethanol water containing an ammoniacal buffer.
5. The method of claim 4 , wherein the ammoniacal buffer is at a pH between about 8.24 and 10.0.
6. The method of claim 1 , wherein the method is performed at room temperature.
7. The method of claim 1 , wherein the incubation step is performed above room temperature.
8. The method of claim 1 , wherein the resacetophenone oxime added to the at least one positive control, negative control and the sample solution is at a concentration of about 1 g/L.
9. The method of claim 1 , wherein the hydrocolloid gel comprises gellan gum.
10. The method of claim 1 , wherein the step of measuring the at least one positive control, negative control and the sample solution for a colorimetric reaction is performed using spectrophotometry.
11. The method of claim 1 , wherein the sample solution is obtained from a water supply.
12. The method of claim 11 , wherein if a colorimetric reaction is observed in the sample solution, performing additional steps of adding ammoniacal buffer to the water supply, wherein the ammoniacal buffer is at a pH of at least 9.25, to sediment manganese and filtering the sedimented manganese from the water supply.
13. A kit for testing for the presence of manganese in a solution, comprising:
a manganese positive control;
a negative control containing no manganese; and
resacetophenone oxime, wherein the resacetophenone oxime is contained within a hydrocolloid gel.
14. The kit of claim 13 , further comprising a multi-well plate.
15. The kit of claim 13 , wherein the hydrocolloid gel comprises gellan gum.