Active carbon in soil II (0.5g soil)


Used with the "Active carbon in soil for Android, 0.5g soil" protocol. See protocol for detailed description. Single measurement of active carbon in soil use potassium permangenate solution. User should have saved calibration values from the active carbon calibration protocol, and blank values from the blank protocol prior to running this.
var output = {};

// Assume that the weight is 0.5 grams
var weight = 0.5;

// perform 5 technical replicates
var sample_raw = MathMEAN(json.data_raw.slice(10,40));

// NOTE! based on uM values for potassium permangenate concentrations
var slope = json.get_userdef7[0]; 
var yint = json.get_userdef7[1];
var blank = json.get_userdef6[0];

var absorbance = MathLOG( ( sample_raw/blank ) ) * -1;
var sample_concentration = (absorbance - yint)/slope;

/*
weight = 2.48;
var slope = .0502; 
var yint = -.00004;
var absorbance = .3087;
*/

var activeCarbon = (0.02 - (yint + slope * absorbance)) * 9000 * (0.02 / (weight/1000)); 
/*
*/

// for testing with field method - should be 327.5
/*
weight = 2.48;
var slope = .0502; 
var yint = -.00004;
var blank = json.get_userdef6[0];
var absorbance = .3087;
var sample_concentration = (absorbance - yint)/slope;
var activeCarbon = (0.02 - (yint + slope) * absorbance) * 9000 * (0.02 / (weight/1000)); // divide by 1000 to convert yint and slope to mM from uM
*/

//Active Carbon (mg kg -1) = [0.02 mol/ L – (a + b × Abs)] × (9000 mg C/ mol) × (0.02 L solution/ Wt)
//[0.02 M – (-0.00004 + (0.0502 × 0.3087)] × (9000 mg C/ mol) × (0.02 L solution/ 0.00248 kg) = 329.75 mg POXC kg -1 soil

output["active carbon"] = MathROUND(activeCarbon,2);
output["absorbance"] = MathROUND(absorbance,3);
output["weight"] = MathROUND(weight,2);
output["sample concentration"] = MathROUND(sample_concentration,4);
output["blank signal"] = MathROUND((blank - sample_raw),1);
output["sample raw"] = MathROUND(sample_raw,1);
output["blank"] = MathROUND(blank,1);
output["slope"] = MathROUND(slope,6);
output["yint"] = yint;

return output;
{
  "time_offset": 240,
  "time": 1436445590507,
  "device_id": 92,
  "firmware_version": "0.422",
  "sample": [
    [
      {
        "time": 1436445590507,
        "protocol_id": 1,
        "get_userdef6": [
          53829.285156,
          0
        ],
        "get_userdef7": [
          0.021289,
          -0.02082
        ],
        "averages": 50,
        "data_raw": [
          64970,
          41212,
          41228,
          41234,
          41245,
          41237,
          41240,
          41242,
          41243,
          41244,
          41248,
          41247,
          41243,
          41246,
          41242,
          41250,
          41245,
          41250,
          41247,
          41254,
          41248,
          41251,
          41249,
          41253,
          41249,
          41249,
          41250,
          41250,
          41250,
          41254,
          41252,
          41250,
          41248,
          41251,
          41253,
          41250,
          41256,
          41251,
          41254,
          41251,
          41253,
          41252,
          41251,
          41253,
          41252,
          41253,
          41249,
          41253,
          41246,
          41254
        ]
      }
    ]
  ]
}
012409 pbi 160 low low res headshot
Created by

Greg Austic


Protocol connections:
1
Latest Update:
Jul 2015