Tintometer Inc.: Lovibond PTV 2000: Continuous measurements of turbidity in drinking water by 660-nm LED

Summary
Analytes
Revision
Data and Sites

Official Method Name

Continuous Measurement of Drinking Water Turbidity Using a Lovibond PTV 2000 660-nm LED Turbidimeter

Current Revision

Revision 1.0, December 28, 2016

Media

WATER

Instrumentation

Nephelometer

Method Subcategory

Physical

Method Source

Tintometer Inc.

Citation

Continuous measurement of drinking water turbidity using a Lovibond PTV 1000 white light LED turbidimeter

Brief Method Summary

The method is based upon a comparison of the intensity of a collimated beam of light that is generated by a 660-nm LED, that is scattered by the sample under defined conditions with the intensity of the same 660-nm light LED light scattered by a standard reference suspension. The higher the intensity of scattered light, the higher the turbidity. Readings, in NTU, are made in a nephelometer.

Scope and Application

Turbidity measurement in any colorless drinking water samples with a turbidity less than 10 Nephelometric Turbidity Units (NTU).

Applicable Concentration Range

0 to 10 NTU

Interferences

(A) Floating debris and coarse particulate matter within the sample may settle out of suspension resulting in low turbidity readings. (B) Finely divided air bubbles will cause random high spikes in readings. Incorporate a sample deaerator for the removal of entrained air from the sample stream. (C) Dissolved, light absorbing substances or chemicals in the sample, i.e., the presence of color, can absorb portions of the incident light spectra, resulting in low turbidity readings, although this effect is generally not significant for drinking water. (D) Light-absorbing particles in suspension within the sample, such as activated carbon of significant concentration, can cause low readings. (E) Construction materials of the nephelometric device within the measurement chamber can result in elevated stray light due to spurious reflections of the incident beam can cause a false positive bias at the bottom end of the range.

Quality Control Requirements

LABORATORY REAGENT BLANK (LRB), PRIMARY CALIBRATION STANDARD (PCAL), QUALITY CONTROL SAMPLE (QCS), SECONDARY CALIBRATION STANDARDS (SCAL), STOCK STANDARD SUSPENSION (SSS), Reagent water, turbidity-free.

Sample Handling

N/A

Maximum Holding Time

N/A

Relative Cost

Sample Preparation Methods

This method has 1 analyte associated with it.

Analyte	Detection Level	Bias	Precision	Pct False Positive	Pct False Negative	Spiking Level
Turbidity(E-10617) Turbidity Water Clarity	0.013 NTU	105% Rec	0.00 RSD (SL)			0.01 NTU

Precision Descriptor Notes:	Accuracy (bias) was determined as percent recoveries relative to the theoretical values for the turbidity spikes compared to results from the reference Hach Method 10133. Precision was determined as the standard deviation for each of the turbidity spikes compared to results from the reference Hach Method 10133.
Detection Level Note:	The detection limit is determined in turbidity-free reagent water including deionized distilled water filtered through a 0.2-µm or smaller pore-size membrane filter if necessary or water produced by reverse osmosis. Water should have a turbidity that is ≤0.030 NTU.

Revision	PDF/Link
Revision 1.0, December 28, 2016

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Tintometer Inc.: Lovibond PTV 2000: Continuous measurements of turbidity in drinking water by 660-nm LED

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