Concentration 1,000 +/- 10 ug/ml Matrix: 5% Nitric Acid NIST Traceable

For all EPA 180.1 turbidimeters. TEST Turbidity 0.8 NTU +/- 0.02 Absorbance at 455nm (100mm pathlength) Lot Number of Baseline Material

Concentration (as nitrite) 1,000 +/- 10 ug/mL Matrix: sodium nitrite, water Refrigerate to maximize shelf life

Concentration 1,000 +/- 10 ug/ml Matrix: 20% Hydrochloric acid NIST Traceable

NIST Traceable, non-toxic reference material for the visible spectrophotometer. Full visible scan reported with a typical absorbance at 600 nm in 10 mm pathlength being approximately 0.368.

AA, colorimetric or volumetric standard

TEST Turbidity (AQ4500) EPA mode Turbidity (AQ4500) ISO Neph. mode Turbidity (AQ4500) IR Ratio mode Thermo Electron AQ4500 serial number Instrument calibration date Formazin Concentrate (

TEST Turbidity (AQ4500) EPA mode 1 NTU +/- 0.05 Turbidity (AQ4500) ISO Neph. mode Turbidity (AQ4500) IR Ratio mode Thermo Electron AQ4500 serial number Instrument calibration date Formazi

TEST Turbidity (Hach 2100N/AN and IS meters) 0.1 NTU Absorbance at 455nm (100mm pathlength) Lot Number of Baseline Material

TEST Turbidity (on Hach 2100 N/AN meter) 4000 NTU Absorbance at 455nm (10mm pathlength) Lot Number of Baseline Material

Concentration (as chlorite) 1,000 +/- 10 ug/mL Matrix: sodium chlorite, water

TEST Turbidity (LaMotte 2020) 10 NTU +/-0.1 Absorbance at 455nm (100mm pathlength) Lot Number of Baseline Material

Concentration (as Cl) 1,000 +/- 10 ug/mL Matrix: KCl, water

TEST Turbidity (on Hach 2100N/AN) 1000 NTU +/- 10 Absorbance at 455nm (10mm pathlength) Lot Number of Baseline Material

Concentration 1,000 +/- 10 ug/ml Matrix: 5% Nitric acid NIST Traceable

NIST Traceable, non-toxic reference material for the visible spectrophotometer. Full visible scan reported with a typical absorbance at 600 nm in 10 mm pathlength being approximately 0.034.

Concentration 1,000 +/- 10 ug/ml Matrix: 5% Nitric acid NIST Traceable

NIST Traceable, non-toxic reference material for the visible spectrophotometer. Full visible scan reported with a typical absorbance at 600 nm in 10 mm pathlength being approximately 0.072.

TEST Turbidity 900 NTU Absorbance at 455nm (10mm pathlength) Lot Number of Baseline Material

Concentration (as chlorate) 1,000 +/- 10 ug/mL Matrix: sodium chlorate, water

TEST Turbidity 600 NTU +/- 6 Absorbance at 455nm (10mm pathlength) Lot Number of Baseline Material

Turbidity 4.0 NTU +/- 0.04 Absorbance at 455nm (100mm pathlength) Lot Number of Baseline Material

Concentration: 1000 +/- 10 ug/mL Matrix: Potassium cyanide in 0.1% sodium hydroxide

TEST Turbidity (OBS sensor inst) 4000 TU +/- 40 Absorbance at 455nm (10mm pathlength) Lot Number of Baseline Material

For all EPA 180.1 turbidimeters. TEST Turbidity 0.6 NTU +/- 0.02 Absorbance at 455nm (100mm pathlength) Lot Number of Baseline Material

TEST Turbidity (on Analite/ISO 7027 probe) 40 NTU Absorbance at 455nm (50mm pathlength) Lot Number of Baseline Material

NIST Traceable, non-toxic reference material for the visible spectrophotometer. Full visible scan reported with a typical absorbance at 600 nm in 10 mm pathlength being approximately 0.767.

TEST Turbidity 30 NTU +/- 0.3 Absorbance at 455nm (100mm pathlength) Lot Number of Baseline Material

NIST Traceable, non-toxic reference material for the UV spectrophotometer. Full UV scan reported with a typical absorbance at 300 nm in 10 mm pathlength being approximately 0.079.

TEST Turbidity (on Analite probe) 100 NTU/FNU Turbidity (on ISO 7027 Instrument) 100 FNU Absorbance at 455nm (10mm pathlength) Lot Number of Baseline Material

TEST Turbidity (on Analite/ISO 7027 probe) 400 NTU Absorbance at 455nm (10mm pathlength) Lot Number of Baseline Material

Concentration 10,000 +/- 100 ug/ml Matrix: 5% Nitric Acid NIST Traceable