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7

Precision

 is how closely repeated measurements 

agree with each other. Precision is usually 
expressed as standard deviation (SD).  

Accuracy

 is defined as the nearness of a test 

result to the true value. 
Although good precision suggests good accuracy, 
precise results can be inaccurate. The figure 
explains these definitions.
In a laboratory using a standard solution of  
50 mg/L nitrate and a representative lot of 
reagent, an operator obtained with a single 
instrument a standard deviation of 5 mg/L.

Absorption of Light is a typical phenomenon of interaction between electromagnetic radiation and 
matter. When a light beam crosses a substance, some of the radiation may be absorbed by atoms, 
molecules or crystal lattices.
If pure absorption occurs, the fraction of light absorbed depends both on the optical path length 
through the matter and on the physical‑chemical characteristics of the substance according to the 
Lambert‑Beer Law: 

‑log 

I

/

I

o

 = 

ε

λ

 

c d 

or 

A  = 

ε

λ

 

c d

Where: 

‑log 

I

/

I

=  Absorbance (A)

 

I

=  intensity of incident light beam

 

=  intensity of light beam after absorption

 

ε

λ

 

=  molar extinction coefficient at wavelength 

λ

 

=  molar concentration of the substance

 

=  optical path through the substance

Therefore, the concentration “c” can be calculated from the absorbance of the substance as the 
other factors are known.
Photometric chemical analysis is based on the possibility to develop an absorbing compound from a 
specific chemical reaction between sample and reagents. Given that the absorption of a compound 
strictly depends on the wavelength of the incident light beam, a narrow spectral bandwidth should 
be selected as well as a proper central wavelength to optimize measurements.

PRINCIPLE OF OPERA

TION

PRECISION AND ACCURACY

Содержание HI96786C

Страница 1: ...INSTRUCTION MANUAL HI96786C Nitrate ISM...

Страница 2: ...anna Instruments product Please read this instruction manual carefully before using the instrument This manual will provide you with the necessary information for correct use of the instrument as well...

Страница 3: ...ISION AND ACCURACY PRINCIPLE OF OPERATION FUNCTIONAL DESCRIPTION ERRORS AND WARNINGS GENERAL TIPS FOR AN ACCURATE MEASUREMENT STARTUP MEASUREMENT PROCEDURE VALIDATION PROCEDURE CALIBRATION PROCEDURE G...

Страница 4: ...e with Sample Cuvettes and Caps 2 pcs CAL Check standard cuvettes 9V Battery Scissors Cloth for wiping cuvettes Instrument Quality Certificate Instruction Manual and Quick Reference Guide Rigid carryi...

Страница 5: ...sparent cup This makes the instruments fulfill field applications Display messages aid the user in routine operation The meter has an auto shut off feature that will turn off the instrument after 10 m...

Страница 6: ...od The reaction between nitrate nitrogen and the reagent causes an amber tint in the sample Environment 0 to 50 C 32 to 122 F max 95 RH non condensing Battery Type 9V 1 pc Auto Shut off After 10 of no...

Страница 7: ...ght absorbed depends both on the optical path length through the matter and on the physical chemical characteristics of the substance according to the Lambert Beer Law log I Io c d or A c d Where log...

Страница 8: ...cuvette has a very important role because it is an optical element and thus requires particular attention It is important that both the measurement and the calibration zeroing cuvettes are optically...

Страница 9: ...meter prior to measurement to confirm edited values or to confirm factory calibration restore READ TIMER this is a multi functional key In measurement mode press to make a measurement or press and hol...

Страница 10: ...gs 3 The battery icon shows the charging level of the battery 4 The hourglass appears when an internal checking is in progress 5 Status messages 6 The chronometer appears when the reaction timer is ru...

Страница 11: ...the light level Please check that the sample does not contain any debris Inverted cuvettes The sample and the zero cuvette are inverted Zero A zero reading was not taken Follow the instructions of th...

Страница 12: ...ers in the analysis cell Assure that the cuvette cap is present Cooling lamp The instrument waits for the lamp to cool down d other errors and warnings Battery low The battery must be replaced soon De...

Страница 13: ...tom of this concavity must be at the same level of the 10 mL mark Proper use of the powder reagent packet a use scissors to open the powder packet b push the edges of the packet to form a spout c pour...

Страница 14: ...stained All the reaction times reported in this manual are at 25 C 77 F In general the reaction time should be increased for temperatures lower than 20 C 68 F and decreased for temperatures higher tha...

Страница 15: ...measured When the beeper sounds briefly and the LCD displays dashes the meter is ready The blinking ZERO indicates that the instrument needs to be zeroed first Fill one cuvette with 10 mL of unreacte...

Страница 16: ...der and ensure that the notch on the cap is positioned securely into the groove Replace the cap and immediately shake vigorously for exactly 10 seconds by moving the cuvette up and down Continue to mi...

Страница 17: ...rt the reading to mg L of nitrate nitrogen multiply by the factor 0 226 INTERFERENCES Interference may be caused by Ammonia and amines as urea and primary aliphatic amines Chloride above 100 mg L nega...

Страница 18: ...ensure that the notch on the cap is positioned securely into the groove When the beeper sounds briefly and the LCD displays dashes the meter is ready The blinking ZERO indicates that the instrument ne...

Страница 19: ...e At the end of the measurement the display will show the validation standard value The reading should be within specifications as reported in the CAL CheckTM Standard Certificate If the value is foun...

Страница 20: ...he blinking ZERO asks for instrument zeroing Place the CAL CheckTM Standard HI96786 11 Cuvette A into the cuvette holder and ensure that the notch on the cap is positioned securely into the groove Not...

Страница 21: ...kTM Standard HI96786 11 Cuvette B into the cuvette holder and ensure that the notch on the cap is positioned securely into the groove Press READ TIMER and the lamp cuvette and detector icons will appe...

Страница 22: ...08 2009 appears on the display or 01 01 2009 if the factory calibration was selected before In both cases the year number is blinking ready for date input CALIBRATION PROCEDURE After measurement the i...

Страница 23: ...ly increased When the correct month has been set press ZERO CFM or READ TIMER to confirm Now the display will show the day blinking Press ZERO CFM to save the calibration date Note It is possible to c...

Страница 24: ...display If no calibration was performed the factory calibration message F CAL will appear on the main display and the instrument returns to measurement mode after three seconds LAST CALIBRATION DATE P...

Страница 25: ...splayed when the instrument is switched on The blinking ZERO means that a new zero has to be performed One fresh battery lasts for around 750 measurements depending on the light level The remaining ba...

Страница 26: ...wise to close To replace the instrument s battery follow the steps BATTERY REPLACEMENT ACCESSORIES Reagent Set HI93728 01 Reagents for 100 tests HI93728 03 Reagents for 300 tests Other Accessories HI9...

Страница 27: ...nts first obtain a Returned Goods Authorization Number from the Customer Service Depart ment and then send it with shipment costs prepaid When shipping any instrument make sure it is properly packaged...

Страница 28: ...a Instruments Inc Highland Industrial Park 584 Park East Drive Woonsocket RI 02895 USA www hannainst com Local Office Hanna Instruments USA 270 George Washington Highway Smithfield RI 02917 Phone 800...

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