Color, True and Apparent, Low Range
Contents
1. Color True and Apparent Low Range DOC316 53 01252 Platinum Cobalt Standard Method1 2 3 Method 8025 LR 3 to 200 units Scope and Application For water wastewater and seawater Equivalent to NCASI method 253 and NCASI Method Color 71 01 for pulp and paper effluent using 465 nm requires pH adjustment 1 Adapted from Standard Methods for the Examination of Water and Wastewater and National Council for Air and Stream Improvement NCASI Methods Manual 2 Adapted from Wat Res Vol 30 No 11 pp 2771 2775 1996 3 NCASI Method 253 approved at 40 CFR part 136 Test preparation How to use instrument specific information The nstrument specific information table shows the sample cell requirements for each instrument To use this table select an instrument then read across to find the sample cell requirements Table 1 Instrument specific information Instrument Sample cell Adapter DR 5000 2629250 A23618 DR 3900 DR 3800 DR 2800 DR 2700 2629250 Before starting the test NCASI procedure requires pH adjustment Adjust the pH to 7 6 with 1 0 N HCI or 1 0 N NaOH When adjusting the pH if overall volume change is greater than 1 start over and use a stronger acid or base Use Program 124 or the 465 nm wavelength program when performing the NCASI procedure One powder pillow of pH 8 Buffer sodium phosphate potassium phosphate may be added to 50 ml of sample prior to final pH adjustment to reduce sample dilution e2. Stored Programs Program setup for the 455 nm method 1 Turn the instrument on and allow the Self Check to complete 2 Follow the display prompts and enter commands for the 455 nm method Table 2 Color True and Apparent Low Range Page 4 of 6 Table 2 LR color 455 nm program setup Step Display shows Enter Select 1 Main Menu User Programs 2 User Programs Program Options 3 Program Options New 4 Program Number 950 999 Select a Program Number OK 5 Program Name LR_Color_455_nm NEXT 6 Program Type Single Wavelength NEXT 7 Units Units NEXT 8 Wavelength nm 455 NEXT 9 Concentration Resolution 1 NEXT 10 Chemical Form PtCo_50_mm NEXT 11 Calibration Enter Formula NEXT 12 Enter Formula b 737 70 OK gt DONE 13 User Program for number assigned Upper Limit EDIT 14 Upper Limit ON gt 220 OK gt OK 15 User Program for number assigned Lower Limit EDIT 16 Lower Limit ON gt 3 OK gt OK gt STORE 3 Exit and select the program number assigned for LR Color at 455 nm from the User Programs menu to run the test Program setup for 465 nm NCASI method 1 Turn the instrument on and allow the Self Check to complete 2 Follow the display prompts and enter commands for the 465 nm method Table 3 LR color 465 nm program setup Step Display shows Enter Select 1 Main Menu User Programs 2 User Programs Program Options 3 Program O
3. the deionized water and rinse the cell at least two times with the filtered sample Fill the sample with filtered sample check for bubbles or smudges and place the cell into the holder to make the measurement Cleaning the sample cells Thoroughly rinse the sample cell with deionized water and dry after making sample measurements Place the cell in a dust free environment and dedicate the cell for LR color measurements only The sample cleaning procedure will only need to be repeated as necessary for future sample measurements Summary of method Color may be expressed as apparent or true color The apparent color includes that from dissolved materials plus that from suspended matter By filtering or centrifuging out the suspended materials the true color can be determined The procedure describes true color analysis If apparent color is desired it can be determined by measuring an unfiltered water sample The stored program is used for both forms of color The stored program is calibrated in color units based on the APHA recommended standard of 1 color unit being equal to 1 mg L platinum as chloroplatinate ion Test results for Programs 121 and 124 are measured at 455 and 465 nm respectively Instrument setup Program setup for the 455 nm method and the 465 nm NCASI method is applicable for the following instruments e DR 2700 e DR 2800 e DR3800 e DR3900 e DR 5000 instruments not having PRGMS 121 and 124 available as
4. No 7 1 6 pkg 2119 07 Tubing rubber 2 4 mm wall 1 12 ft 560 19 Recommended standards Description Unit Catalog number Color standard solution 500 platinum cobalt units ie 1414 53 Color standard solution 15 platinum cobalt units 1L 26028 53 Optional reagents and apparatus Description Unit Catalog number Detergent Liqui Nox 1L 20881 53 Filter Glass Microfiber 47 mm 1 0 micron 100 pk 2551400 Flask volumetric Class A 500 mL each 14574 49 Hydrochloric acid 6 0 N 1 1 500 mL 884 49 Pipet volumetric Class A 15 00 mL each 14515 39 Pipet filler safety bulb each 14651 00 Sample cell 5 cm 50 mm pathlength rectangular quartz each 26244 50 Wipers disposable 280 pk 20970 00 race Hach Company 2008 2010 2012 All rights reserved Printed in the U S A FOR TECHNICAL ASSISTANCE PRICE INFORMATION AND ORDERING In the U S A Call toll free 800 227 4224 Outside the U S A Contact the HACH office or distributor serving you On the Worldwide Web www hach com E mail techhelp hach com HACH COMPANY WORLD HEADQUARTERS Telephone 970 669 3050 FAX 970 669 2932 Edition 3
5. cm 50 mm pathlength cell with 10 mL of filtered deionized water Discard the excess water in the flask Drain the flask well to avoid diluting 3 Assemble the filtering apparatus 0 45 micron membrane filter filter holder filter flask and aspirator NCASI Test prescribes a 0 8 micron filter A 1 0 micron prefilter can be first used for difficult to filter samples 7 Carefully wipe the blank and check the cell for air bubbles or smudges on the cell windows Insert the cell into the cell holder DR 2700 DR 2800 DR 3800 and DR 3900 instruments Slide the cell against the right wall of the sample cell compartmentto consistently orient the cell Close the lid i 4 Rinse the filter by pouring approximately 50 mL of deionized water through the filter Discard the rinse water MeN 8 Push ZERO The display will show 0 units PtCo_50 mm A N05 z IL om 9 Pour about 50 mL of 10 Prepared Sample 11 Wipe the prepared sample through the filter Remove the blank from sample and check for air the cell holder Discard the bubbles or smudges on deionized water Rinse the the cell windows cell with the filtered sample and then fill with 10 mL of sample Insert the cell into the cell holder Close the lid Press READ Results are in PtCo color units Sample collection preservation and storage Collect samples in clean plastic or glass bottles Mos
6. ffects Mix thoroughly to dissolve before making final pH adjustments A minimum of 6 mL of sample is required for use with the 5 cm cell See Method technique on page 3 for precautions in doing low level color measurements Insert an adapter if required Refer to the user manual for orientation To test for apparent color omit steps 3 to 5 Use unfiltered deionized water in Step 6 and unfiltered sample in Step 10 Collect the following items Quantity Buffer pH 8 0 Program 125 1 Hydrochloric acid solution 1 0 N NCASI method at 465 nm only varies Sodium hydroxide 1 00 N Program 124 NCASI method at 465 nm only varies Water deionized 100 mL Filter apparatus membrane filter filter holder filter flask and aspirator 1 Sample cell 5 cm glass 1 Stopper rubber one hole No 7 1 1 Tubing rubber Color True and Apparent Low Range Page 1 of 6 Color True and Apparent Low Range Platinum Cobalt Standard Method Stored Programs 121 LR Color 455 nm OR 124 LR Color 465 nm Start 1 Select the test NCASI Use program 124 for the LR NCASI test Refer to Instrument setup on page 4 for programming instructions 5 Pour another 50 mL of deionized water through the filter Color True and Apparent Low Range Page 2 of 6 2 Collect 200 mL of 400 mL beaker NCASI Adjust the pH as Test preparation on page 1 _ 6 Blank Preparation Fill a 5
7. ptions New 4 Program Number 950 999 Select a Program Number OK 5 Program Name LR_Color_465_nm NEXT 6 Program Type Single Wavelength NEXT 7 Units Units NEXT 8 Wavelength nm 465 NEXT 9 Concentration Resolution 1 NEXT 10 Chemical Form PtCo_50_mm NEXT 11 Calibration Enter Formula NEXT 12 Enter Formula b 764 00 OK gt DONE 13 User Program for number assigned Upper Limit EDIT 14 Upper Limit ON gt 220 OK gt OK 15 User Program for number assigned Lower Limit EDIT 16 Lower Limit ON gt 3 OK gt OK gt STORE 3 Exit and select the program number assigned for LR Color at 465 nm from the User Programs menu Color True and Apparent Low Range Page 5 of 6 Color True and Apparent Low Range Consumables and replacement items Required reagents Description Quantity Test Unit Catalog number Buffer pH 8 0 1 15 pK 1407995 Hydrochloric acid solution 1 0 N varies 1L 23213 53 Sodium hydroxide 1 00 N varies 900 mL 1045 53 Water deionized 50 mL 4L 272 56 Required apparatus Description Quantity Test Unit Catalog number Aspirator nalgene vacuum pump 1 each 2131 00 Filter holder magnetic 300 mL graduated 47 mm 1 each 13529 00 Filter membrane 47 mm 0 8 microns for NCASI procedure 1 100 pkg 26408 00 Filter membrane 47 mm 0 45 microns 1 100 pkg 28947 00 Flask filtering 500 mL 1 each 546 49 Sample cell 5 cm 50 mm pathlength rectangular glass 1 each 26292 50 Stopper rubber one hole
8. r Carefully wipe the cell windows with a lint free towel 3 View the cell through the cell windows to check for trapped air bubbles or traces of lint or smudges on or in the cell 4 Tap the cell lightly on a bench or table to dislodge any trapped air bubbles Color True and Apparent Low Range Page 3 of 6 Color True and Apparent Low Range 5 Orient the cell in the cell holder and zero the instrument Insert the cell completely into the cell holder of the sample cell compartment Step 7 on page 2 Close the lid Note The cell may initially fit tightly in the DR 5000 sample cell holder but will loosen slightly with additional use There may be slight variability between cell manufacturers 6 Remove the cell and repeat the above procedure for cleaning the cell 7 Fill the cell again with deionized water and place in the cell holder and read the value The instrument should read 0 if the sample cell is properly cleaned no bubbles are present and the cell is consistently oriented in the cell holder Filtering the sample It is questionable if apparent color values are meaningful in low level color measurements Any turbidity or suspended particles will contribute to the measured color value and will cause high results It is recommended that all samples for low level color measurements be first filtered through a membrane filter and the results be reported as true color After the instrument has been zeroed discard
9. t reliable results are obtained when samples are analyzed as soon as possible after collection If prompt analysis is impossible fill bottles completely and cap tightly Avoid excessive agitation or prolonged contact with air Samples can be stored for 24 hours by cooling to 4 C 39 F Warm to room temperature before analysis Accuracy check Standard solution method Use a 15 Platinum Cobalt Color Standard to fill a 5 cm cell Carefully wipe the cell check for air bubbles and use in place of sample in Step 10 Alternately a 15 mg L Pt Co standard can be prepared by pipetting 15 0 mL of a 500 Pt Co color standard into a 500 mL volumetric flask and diluting to volume with deionized water Method performance Precision 95 confidence Sensitivity Program Standard limits of distribution Concentration change per 0 010 Abs change 455 nm 15 units Pt Co 14 to 16 units Pt Co 7 4 units Pt Co 465 nm 15 units Pt Co 14 to 16 units Pt Co 7 6 units Pt Co Method technique Zeroing and reading the sample It is important to use extremely good lab technique and attention to detail in order to obtain reproducible results on waters that have true color values of less than 15 Pt Co color units 1 Wash the 5 cm sample cell with soap and water or acid rinse the cell to remove any traces of dirt grease finger prints etc Rinse several times with filtered deionized water 2 Fill the cleaned cell with at least 6 mL of deionized wate
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