Table 1.
Potential Interferent | Max. Conc. Tolerated 1 | % Inhibition | Std dev (%) |
---|---|---|---|
Bacillus cereus spores | 106 cfu/mL | 11.8 | 11.0 (n = 8) |
Bacillus mycoides spores | 106 cfu/mL | 11.1 | 9.1 (n = 8) |
Bacillus thuringiensis spores | 106 cfu/mL | 5.6 | 10.1 (n = 10) |
Calcium Chloride | 75 mM | 9.0 | 8.2 (n = 11) |
Magnesium Chloride | 100 mM | 9.5 | 6.4 (n = 11) |
Magnesium Sulfate | 75 mM | 10.4 | 3.9 (n = 11) |
Potassium Chloride | 150 mM | 14.3 | 6.3 (n = 9) |
Sodium Chloride | 150 mM | 14.6 | 4.3 (n = 8) |
Sodium Phosphate (pH 7.0) | 50 mM | 12.9 | 6.6 (n = 8) |
Low pH (sodium citrate pH 5.0) | 50 mM | 14.9 | 6.1 (n = 8) |
High pH (sodium borate pH 10.0) | 50 mM | 10.6 | 6.2 (n = 8) |
Phenol | 1.0% (v/v) | 6.7 | 6.1 (n = 10) |
Potting soil extract | 1.0% (w/v) | 13.1 | 11.7 (n = 30) |
Local soil extract 2 | 1.0% (w/v) | 11.0 | 8.0 (n = 13) |
1 Defined as the maximum concentration of interferent causing less than 20% average inhibition of assay signal compared with control samples in water with 0.1% Tween 20. 2 Local soil was collected outside our laboratory in Aiea, HI, USA.