Table 4. Summary of Certified Reference Material Measurements

Measurement	TALK µmol/kg	pH @ 25°C	Total runs
System A	2253.6 ± 4.1	7.826 ± 0.006	53
System B	2257.2 ± 2.0	7.826 ± 0.005	60
Combined	2255.5 ± 3.0	7.826 ± 0.006	113
Spectrophotometer
CRM Batch 73		7.8417 ± 0.0020	9
TRIS		8.0525 ± 0.0033	32
Certified Values
CRM Batch 73	2253.5	7.8417