## HACH COMPANY

Validation Study Report Hach Company SPADNS 2 (Arsenic

- Free) Fluoride Method 10225

Prepared by:
Dr. Cary B. Jackson

8/20/2010Validation Study Report Hach Company SPADNS 2 (Arsenic

- Free) Fluoride Method 10225

2 Background

Purpose of Study The purpose of this study was to evaluate the proposed Hach Company

SPADNS 2 ( Arsenic

- Free) Fluoride Method 10225 against the USEPA reference fluoride method (SM4500

- F D ) for approval and use in USEPA regulatory drinking water

programs.

Method Summary Fluoride reacts with a zirconium SPADNS dye. The loss of color during this reaction is proportional to the fluoride concentration in the sample. The SPADNS 2 reagent contains a non

- toxic species to prevent chlorine interference rather than sodium
arsenite that is used in the reference method . Test results are measured at 580 nm.

Method Justification

The presence of chlorine and its oxid izing capability is a known interferen ce i n the measurement of fluoride with SPADNS chemistry. To mitigate this interfer ence, the
USEPA reference method calls for the addition of sodium arsenite. However, arsenite is a highly toxic chemical that is hazardous to the environment. The SPADNS 2 method replaces sodium arsenite with a non

- toxic and non

- hazardous a proprietary c hlorine scavenger that produces results that are equivalent or better than the SPADNS arsenite

method.

Scope of Method

The SPADNS 2 method is applicable for use in drinking water, surface and saline
waters, and domestic and industrial wastewaters. The m easurement range for this

method is in the range from 0.10 to 2.00 mg F

- /L.

Study Design and Objectives

The design and objectives of this validation study are detailed in the Validation Study Plan 1 appended to this report.

1 Revised Hach Validation Study Plan, August 2010Validation Study Report Hach Company SPADNS 2 (Arsenic

- Free) Fluoride Method 10225

3 Study Implementation

Study Sponsor The organizational sponsor responsible for managing this study is Hach Company.

Study Participants The participants, laboratories, and test matrices were selected from geographically diverse regions of the United States and are listed in the following table.

Matrix Facility Laboratory Source of Treated Test
Water Loveland, Colorado Water
Treatment Plant Hach Company Surface water from river

Roseville, California Water
Treatment Plant Roseville, California Water
Treatment Plant Surface water from river

Storm Lake, Iowa Water
Treatment Plant Storm Lake, Iowa Water
Treatment Plant Ground Water

Tier Study The validation study was performed under Tier II requirements.

Sample Collection and Distribution Matrix samples for this validation study were collected at the tap for each laboratory. Collection followed standard USEPA sampling procedures 2

.

Analysis Description The description of the type and number of analyses are described in the Validation Study Plan appended to this report.

Data Reporting and Validation

Data reporting and validation of data are described by the following processes:

Data Collection , Laboratory Submission , and Validation For each laboratory performing analyses, results from each test measurement

wer e read from a Fluoride P ocket C olorimeter II and manually transferred to an

2 40CFR 141.23Validation Study Report Hach Company SPADNS 2 (Arsenic

- Free) Fluoride Method 10225

4 electronic spread sheet. Each laboratory then submitted the electronic spread sheet to the Hach Study Director for review and statistical evaluation.

Results

Summary results of the validation study are listed in Tables 1

- 3.

**Table 1**

**- City of Roseville Water Treatment Plant Summary Results** 

**Matrix Standard Method 4500** 

**- F D**  **Hach Method 10225** 
**Method**
**Detection Limit (mg/L)**  **Minimum Quantitation**  **(mg/L) Method** 
**Detection**
**Limit (mg/L)**  **Minimum Quantitation**  **(mg/L)**

Low Ionic Strength Reagent
Water 0.08 0.30 0.04 0.10

**High Ionic Strength**  **Reagent**
**Water** 0.06 0.20 0.05 0.20

**Initial Precision and Recovery**  **Initial Precision and Recovery**  **Average Percent (%)** 

**Recovery Standard** 
**Deviation Average**  **Percent (%)**

**Recovery Standard** 
**Deviation**

Low Ionic Strength Reagent
Water 103 0.03 101 0.03

**High Ionic Strength**  **Reagent**
**Water** 100 0.03 106 0.02

**Matrix Analysis Matrix Analysis** 

**Average**

**Result (mg/L)**  **Percent (%)**
**Relative**
**Standard**
**Deviation Average** 
**Result (mg/L)**  **Percent (%)**
**Relative**
**Standard**
**Deviation**
**Roseville Tap**  0.93 2.4 0.90 2.7Validation Study Report Hach Company SPADNS 2 (Arsenic

- Free) Fluoride Method 10225

5 **Table 2**

**– Storm Lake Treatment Plant Summary Results** 

**Matrix Standard Method 4500** 

**- F D**  **Hach Method 10225** 
**Method**
**Detection Limit (mg/L)**  **Minimum Quantitation**  **(mg/L) Method** 
**Detection Limit (mg/L)**  **Minimum Quantitation**  **(mg/L)**

Low Ionic Strength Reagent
Water 0.11 0.40 0.08 0.20

**High Ionic Strength**  **Reagent**
**Water** 0.05 0.20 0.05 0.20

**Initial Precision and Recovery**  **Initial Precision and Recovery**  **Average Percent (%)** 

**Recovery Standard** 
**Deviation Average**  **Percent (%)**

**Recovery Standard** 
**Deviation**

Low Ionic Strength Reagent
Water 95 0.02 99 0.02

**High Ionic Strength**  **Reagent**
**Water** 96 0.02 100 0.02

**Matrix Analysis Matrix Analysis** 

**Average**

**Result (mg/L)**  **Percent (%)**
**Relative**
**Standard**
**Deviation Average** 
**Result (mg/L)**  **Percent (%)**
**Relative**
**Standard**
**Deviation**
**Storm Lake Tap**  1.22 2.2 1.23 1.4Validation Study Report Hach Company SPADNS 2 (Arsenic

- Free) Fluoride Method 10225

6 **Table 3**

**– Loveland/Fort Collins Water Treatment Plant** 

**Matrix Standard Method 4500** 

**- F D**  **Hach Method 10225** 
**Method**
**Detection Limit (mg/L)**  **Minimum Quantitation**  **(mg/L) Method** 
**Detection Limit (mg/L)**  **Minimum Quantitation**  **(mg/L)**

Low Ionic Strength Reagent Water 0.02 0.10 0.02 0.10

**High Ionic Strength**  **Reagent Water** 0.07 0.20 0.02 0.20

**Initial Precision and Recovery**  **Initial Precision and Recovery**  **Average Percent (%)** 

**Recovery Standard** 
**Deviation Average**  **Percent (%)**

**Recovery Standard** 
**Deviation**

Low Ionic Strength Reagent Water 102 0.01 100 0.01

**High Ionic Strength**  **Reagent Water** 106 0.01 102 0.01

**Matrix Analysis Matrix Analysis** 

**Average**

**Result (mg/L)**  **Percent (%)**
**Relative**
**Standard**
**Deviation Average** 
**Result (mg/L)**  **Percent (%)**
**Relative**
**Standard**
**Deviation**

**3**

0.96

**Love land**  **/Fort Collins Tap**  **(non**

**- distilled)**  0.7 0.94 0.6

**4**

1.01

**Loveland/Fort Collins Tap**  **(distilled)** 7.4 1.00 7.9

3 Matrix collected on June 8, 2010

4 Matrix Collected on August 9, 2010Validation Study Report Hach Company SPADNS 2 (Arsenic

- Free) Fluoride Method 10225

7 Development of QC Acceptance Criteria

Development of quality control acceptance criteria for method detection limit (MDL) and initial precision and recovery (IPR) followed the criteria detailed in Appendix D, Tier 2 of

Section 9 of the guidance document for EPA approval of new methods 5 . A summary of the pooled quality control acceptance criteria is described in Table 4.

**Table 4**

**– Pooled Statistical Results** 

**Matrix Standard Method 4500** 

**- F D**  **Hach Method 10225** 

**Method**
**Detection**
**Limit (mg/L)**  **Minimum Quantitation**  **(mg/L) Method** 
**Detection Limit (mg/L)**  **Minimum Quantitation**  **(mg/L)**

Low Ionic Strength Reagent
Water 0.06 0.20 0.04 0.10

**High Ionic Strength**  **Reagent**
**Water** 0.05 0.15 0.03 0.10

**Initial Precision and Recovery**  **Initial Precision and Recovery** 

**6 Precision of**  **Recovery (RSD)**  **Percent (%) Recovery** 

**Range 6**  **Percent (%) Recovery** 

**Range Precision of**  **Recovery (RSD)** 

Low Ionic Strength Reagent
Water **Lower**
**Limit Upper** 
**Limit** 0.02 **Lower**
**Limit Upper** 
**Limit** 0.02

84 116 95 105

**High Ionic Strength**  **Reagent**
**Water Lower** 
**Limit Upper** 
**Limit** 0.02 **Lower**
**Limit Upper** 
**Limit** 0.02

82 119 93 113

5 Protocol for EPA Approval of New Methods for Organic and Inorganic Analytes in Wastewater and Drinking
Water, March 19 99 EPA

- 821

- 98

- 003

6 95% ConfidenceData Analysis/Discussion

MDL Results Method detection limit results for from each laboratory yielded expected results from that of Hach Company single

- laboratory data. The range of results of the LIS matrix

were 0.02 m g/L F - to 0.11 mg/L F - for the reference method and 0.02 mg/L F to 0.08 mg/L F for the Hach method. For the reference HIS matrix, the range was 0.05 mg/L F to 0.07 mg/L F - and 0.02 mg/L F - to 0.07 for the Hach method.

Initial precision and recovery results were similar and yielded expected results from that of Hach Company single

- laboratory data. The range of recovery results of the LIS

matrix were 95% to 103% for the reference method and 99% to 101% for the Hach

method. For the reference HIS matri x, the recovery range was 96% to 106 % mg/L F and 0.02 mg/L F - to 0.07 and 100% to 106% for the Hach method. For both the LIS and HIS matrix, the range of precision (standard deviation) for the reference method 0.01 to
0.03 and likewise, 0.01 to 0.03 for the Hach method.

Matrix result %RSDs ranged from 0.7 to 2.4 for the reference method and 0.6 to 2.7 for the Hach method. An addition to the three sets of matrix sample analyses, the Loveland/Fort Collins laboratory performed a distillation analysis. Th e %RSD of the

distilled matrix with the reference method was 7.4% and 7.9 % with the Hach method.

Conclusions

A validation study was conducted to compare the performance of the Hach Method to that of the EPA approved reference method. Laboratory result s from each of the laboratories indicate that the Hach Method 10025 is equally effective in mitigating chlorine interference and analytical performance for the determination of fluoride to that

of the EPA reference method SM 4500

- F D.Validation Study Report Hach Company SPADNS 2 (Arsenic

- Free) Fluoride Method 10225

9 Appendi ces

**Appendix A**

– EMMC formatted Hach Method 10025 (Hach Method 10025 SPADNS

II. pdf )

**Appendix B**

– Revised Validation Study Plan (SPADNSIIValidationPlan. pdf )

**Appendix C**

– Supporting Data (Supporting Data.xls )