HACH LANGE 2100N User Manual
                                              | |
Contents
| 
If possible, do not use heat to accelerate degassing. Heat may changethe properties of the suspended particles and cause volatile componentsto come out of the solution.Gentle heat may be used to remove bubbles from very viscous sampleswhen used with vacuum or ultrasound. If applying heat to the sample isnecessary, do so only as much as is necessary to complete degassing.Before measurement, decrease the temperature of the sample to theinitial temperature, then gently invert the sample.Prevent condensation on a sample cellCondensation may occur on the outside of the sample cell whenmeasuring a cold sample in a warm, humid environment. Thiscondensation or fogging of the sample cell interferes with turbiditymeasurement.To prevent condensation:• Make sure that the outside of the sample cell is dry beforemeasurement.• Use the air purge system as necessary. Refer to Using the air purgesystem on page 27.• If condensation occurs while using the air purge system, warm thesample slightly. Let the sample sit at room temperature or partially putthe sample into a warm water bath for a short time. Gently invert thesample cell before measurement.Note: Warming may change the sample turbidity. Measure the sample withoutwarming when possible.Measure over-range samplesThe nephelometric method of turbidity measurement depends on lightscattering from suspended particles. If turbidity is very high, significantamounts of light may be absorbed by the particles, and little light isavailable for scattering. This results in a negative interference causingthe measured turbidity to be lower than the actual turbidity. Thiscondition is called “going blind”.Methods used to prevent the instrument from going blind include:• Turn Ratio on. Ratio on mode decreases the effects of light absorbingparticles, color, absorbance and high turbidity interferences.• Sample dilution. Refer to Sample dilution on page 23.When too much light is absorbed by the sample, the lamp icon on theinstrument display flashes.Sample dilutionUse filtered sample, deionized water or distilled water for sampledilution. Measure sample dilutions soon after they are prepared.To prepare filtered sample, use the sample filtration and degassing kit.Refer to the user instructions provided with the sample filtration anddegassing kit.If the filters in the sample filtration and degassing kit plug quickly, use astandard 47 mm filtration apparatus shown in Figure 6 with a membranefilter or use a glass-fiber filter. Refer to Accessories on page 40.After dilution and measurement, calculate the actual turbidity as follows:1. Calculate the total volume:Total volume = sample + dilution waterExample: 20 mL of sample and 80 mL of dilution waterTotal volume = 20 mL + 80 mL = 100 mL2. Calculate the dilution factor:Dilution factor = total volume ÷ sample volumeExample: Dilution factor = 100 ÷ 20 = 53. Calculate the actual turbidity:Actual turbidity = measured value × dilution factorExample: Measured value = 2450 NTUActual turbidity = 2450 × 5 = 12,250 NTUEnglish 23 |
Related manuals for HACH LANGE 2100N
This manual is suitable for:
manualsdatabase
Your AI-powered manual search engine