RQflex ® - the pocket laboratory for quantitative on-site measurements in agriculture and horticulture 21-02-2003.

RQflex® - the pocket laboratory for quantitativeon-site measurements in agriculture and horticulture

21-02-2003

10.06.2002 RQ in Agriculture Page 2

The Reflectoquant® System

1. The instruments RQflex® and RQflex® plus

2. The tests Reflectoquant® test strips Reflectoquant® plus test kits

3. The barcode contains all information to operate the instrument



The instruments

RQflex® - the basic instrument quantitative evaluation of Reflectoquant® test strips.

RQflex® plus - with an additional benefitquantitative evaluation of Reflectoquant® test strips and

Reflectoquant® plus test kits


Principle of reflectometry

Kubelka-Munk equationEmitted light is absorbed by the coloured paper.The analyte concentration can be calculated from the amount of absorbed light.

I0 I

diffusereflectance



The double optic system andthe two reaction zones on thetest strip allow a simultaneousdouble measurement in one operational step.

The barcode controlled software calculates the meanwhich is displayed.

Double beam optics for increased accuracy



Memory and documentation

• Storage of 5 different methods simultaneously

• Storage of 50 measurement results

• Data transfer to PC with RQdata interface and software for documentation



RQdata print-out

RQflex Memory

Date: 28.07.1999User: Martina Unger-Heumann

Meth.No. Date Time Value Unit Method

1 26.06. 8:00 45 mg/l Nitrate26.06. 8:02 42 mg/l Nitrate26.06. 8:03 44 mg/l Nitrate26.06. 10:47 153 mg/l Nitrate27.06. 13:22 95 mg/l Nitrate27.06. 13:23 97 mg/l Nitrate

2 26.06. 8:15 0.57 g/l Potassium26.06. 8:18 0.63 g/l Potassium27.06. 11:31 1.15 g/l Potassium27.06. 11:35 1.10 g/l Potassium

3 06.06. 14:15 15 mg/l Phosphate06.06. 14:17 17 mg/l Phosphate06.06. 14:19 19 mg/l Phosphate06.06. 14:25 43 mg/l Phosphate06.06. 14:28 44 mg/l Phosphate



The Reflectoquant® tests

The product range includes

• 50 different Reflectoquant® test stripsfrom Aluminium to Urea

• 6 different Reflectoquant® plus test kitsfrom Chlorine to Phosphate



The Reflectoquant® test strips

The Reflectoquant® test strips are chemical microchips ona few mm2

The reaction zones are impregated with traces of all necessary chemicals, e.g. dyes, buffers, reducing agents,

etc.



The main features of test strips and test kits

The Reflectoquant® test strips are very easy to use: dip - wait - measure. They detect analyte concentrations down to 1 - 10 mg/l.

The Reflectoquant® plus test kits provide high sensitivity down to 10 - 50 µg/l, but are less convenient than a strip.



The barcode

contains

• information about the parameter• lot-specific calibration data• factors for wavelength control



Proven accuracy

• The Reflectoquant technology uses a 10 point calibration

• More than 750 measurement data are used to produce the calibration data on the barcode.



Quality assurance test record



Application in Agriculture and Horticulture

• Determination of nutrients in soil

• Determination of nutrients in plant sap

• Analysis of hydroponic solutions

• Analysis of fertilizer



Sample preparation for agricultural applications

Precondition # 1: Need a liquid sample

Sample preparation:

• extract sample

• squeeze sap

• dilute sample



Sample preparation for soil analysis

Weigh soil sample intoa beaker

Homogenizesoil samplewith extractionsolution

Filter througha filter paper

Dip the test stripinto the solutionand start themeasurement with RQflex®



Measurement procedure Reflectoquant® Nitrate

Press ON/OFF, select TEST and pressSTART; reaction time is displayed

Dip test strip into sample solution andat the same time press START again

5 sec before reaction time endsinsert strip into strip adapter

Read off result from the display

1 2

43



0

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80

90

0 10 20 30 40 50 60 70 80 90

n = 27r = 0.993y = 0.95x + 2.34

German standard method

Nitrate in soil from hops field [mg/kg]

RQ

flex

Dr. B. LehmannUniversity of MunichDept. of Agriculture



Detailed application notes available

Reagents:Reflectoquant® Nitrate Test, Cat.No. 1.16971.0001 or 1.16995.0001Reflectometer RQflex®, Cat.No. 1.16970.0001Calcium chloride dihydrate, Cat.No. 1.02382.0500

Sample preparation:Homogenise ca. 100 g (exactly weighed) of soil sample with 100 ml of 0.01M CaCl2solution by shaking for 30 minutes. Filter through nitrate-free filter paper.

Analysis:Press the reflectometer START key and simultaneously dip the analytical test strip intothe sample (15 - 30°C) for ca. 2 seconds, ensuring that both reaction zones areimmersed. Remove all excess liquid from the strip.Wait 60 seconds and then measure the strip in the reflectometer. The value [mg/l] willbe stored automatically. (Please refer to the RQflex® operating instructions and thepackage insert of the Reflectoquant® Nitrate Test).

Calculation:

Measured value [mg/l] x Vol. CaCl2 sol.[ml]Nitrate content [mg/kg] = ___________________________________

Weight of sample [g]

Conversion to kg nitrate-N/hectare (layer of soil):

kg nitrate-N/ha = A x BF x 3 x D x 0.226

where:

A = Measured valueBF = Factor for wetness of soil and extraction

= 1.41 at an extraction ratio of 1:1 and 83% dry mass3 = For a 30 cm thick layer of soilD = Soil density (1.5 kg/dm3)

0.226 = Conversion factor NO3 into NO3-N

Nitrate in Soil Samples

Method: Reflectometric determination after reductionto nitrite and reaction with Griess reagentreagents

samplepreparation

comparisondata

measurementprocedure

calculation



Measurement procedure Reflectoquant® Phosphate

Press ON/OFF, select TEST and pressSTART; reaction time is displayed

Take 5 ml sample and add 10 drops ofreagent PO4-1

Dip test strip into sample solution andat the same time press START again

5 sec before reaction time endsinsert strip into strip adapter

1 2

43 5

Readresult



0

10

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30

40

50

60

0 10 20 30 40 50 60

n = 20r = 0.991y = 1.11x - 2.15

German standard method

Phosphate in soil [mg/100 g P2O5]

RQ

flex

Prof.Dr. R. GromesUniversity of OsnabrückDept. of Agriculture



Sample preparation for plant sap analysis

Squeeze plant sample througha garlic press

Take 0.1 ml plant sap and dilute it in an appropriateratio with deionized water




0100020003000400050006000700080009000

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

cabbage cucumber spinach

n = 24r = 0.996y = 1.01x + 0.1

Ion Chromatography

Nitrate in sap from different plants [mg/l]

RQ

flex

M. Takebe, T. YoneyamaNational Agriculture Research CenterTsukuba, Japan



Potassium in plant sap

reagentssamplepreparation

typicalresults

measurementprocedure

calculation

Reagents:Reflectoquant® Potassium Test, Cat.No. 1.16992.0001Reflectometer RQflex® plus or RQflex®, Cat.No. 1.16955.0001 or 1.16970.0001

Sample preparation:Use an appropriate method to extract the sap from the plant to be analysed (e.g. a juiceextractor). Dilute the sap 1:10 with deionized water (1 part plant sap to 9 parts water)and mix thoroughly.

Analysis:Immerse both reaction zones of the analytical test strip in the diluted sample solution(15 - 30ºC) for approx. 2 seconds. Vigorously shake off excess liquid from the test strip.Press the reflectometer START button and at the same time place the analytical teststrip in the minitube containing reagent K-1.After the end of the waiting time (60 seconds), immediately remove the test strip, shakeoff excess liquid and then measure the strip in the reflectometer. The value [g/l] will bestored automatically. (Please refer to the RQflex® operating instructions and thepackage insert of the Reflectoquant® Potassium Test).

Calculation:

Potassium content [g/l] = Measured value [g/l] x 10

Results:

Sample Reflectoquant[g/l]]

Sap of beet leaves 6,9Sap of maize leaves 4,0

NB:If the potassium content is below 2,5 g/l it is recommended to dilute the sap 1:500 andto use the Reflectoquant® plus Potassium Test, Cat.No. 1.17945.0001, and thereflectometer RQflex® plus for the analysis. In this case the displayed result has to bemultiplied by 500.

Potassium in Plant Sap

Method: Reflectometric determination after reactionwith dipicrylamine



Sample preparation for hydroponic solutions

Mostly no sample preparation necessary.

In some cases a dilution step is necessary.



0

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140

160

180

0 20 40 60 80 100 120 140 160 180

n = 13r = 0.984y = 0.97x + 3.95

AAS

Calcium in hydroponic solutions [mg/l]

RQ

flex



Sample preparation for natural fertilizer

Weigh fertilizer sample intoa beaker

Homogenizesample withextractionsolution

Filter througha filter paper


(comparable to soil analysis)



0

1

2

3

4

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8

9

0 1 2 3 4 5 6 7 8 9 10

n = 17r = 0.937y = 0.95x + 0,17

Kjeldahl distillation

Ammonium in natural fertilizer [g/kg NH4-N]

RQ

flex



Comparison of costs and time

(standard method vs. Reflectoquant® system)

Standard method Reflectoquant® system

Result after 2-4 weeks after 1 day

Costs 20 USD/sample approx. 7 USD/sample

large scale trial with 651 soil samples

Coefficient of correlation: r = 0.92



Centralized vs. decentralized analyses

Transport to lab

Sampling

Preservation andintermediate storage

Sample preparation

Analysis in lab

Recommendation forapplication of fertilizer

Sample preparation

Fast analysis on-site

after 1-4 weeks after some hours



Your benefits

• Fast results allow to take immediate decisions

• Convincing price/performance ratio saves your money

• Easy handling requires minimum training even for less skilled persons

• Detailed application notes provide support and solve analytical problems



Award

At the International Agricultural Trade Show

INTERSIMA 94

in Paris the RQflex® won the



Recommendation

RQflex® and Reflectoquant® Nitrate Test are

SPAD - recommended in Japan

SPAD is a governmental project on Soil and Plant Analyzer Development.The project is organized by the Japanese Association for AgricultureIndustry.Goal is the practical application of instruments and methods for theanalysis of soil and plants.


RQflex ® - the pocket laboratory for quantitative on-site measurements in agriculture and horticulture 21-02-2003.

Documents

reflectoquant system

reflectoquant technology

test kits

instrument slide

main features of test

quality assurance test

double optic system

measurement data