Universidad Andina Simón Bolívar Área de Salud

Universidad Andina Simón Bolívar
Área de Salud
Programa de desarrollo para Red de Laboratorios
Programa Regional Intercultural para la Investigación, Entrenamiento y
Comunicación en Tecnología para el Buen Vivir, Soberanía y
Bioseguridad
PROPUESTA DE INVESTIGACIÓN PARTICIPATIVA CON LOS PRODUCTORES Y REGANTES DEL CANAL DE RIEGO DE TABACUNDO Antecedentes En el último trimestre del año 2011, en el marco de un estudio sobre dinámicas del riego y agroindustria, se dieron acercamientos entre el Área de Salud de la Universidad Andina Simón Bolívar (UASB), la Corporación de Organizaciones para el Manejo Integral de Agua (CODEMIA) y el Sistema de Investigación de la Problemática Agraria en el Ecuador (SIPAE). Ésos acercamientos abrieron la posibilidad de trabajar en una iniciativa de investigación participativa en torno a los aspectos de agua, producción, ambiente y salud en el área de influencia del Sistema de riego Tabacundo, el mismo que está bajo administración de CODEMIA. Esos acercamientos involucraron luego a profesionales vinculados a la Universidad de British Columbia (Canadá); con ello, la posibilidad de que ésta iniciativa de las instituciones ecuatorianas se inserte en el proyecto de investigación sobre “Sistemas alimentarios y la equidad en salud en la era de la globalización: Pensar, Comer y Crecer Verde en el Mundo (TEG3)” que dicha Universidad canadiense viene desarrollando con la UASB. Si se consideran los objetivos del proyecto de investigación TEG 3 y, sus fundamentos metodológicos entre los que se destacan la combinación de “dos movimientos interdependientes: investigación-­‐acción y síntesis intercultural e interdisciplinaria, parece plenamente justificado la idea de que la iniciativa inicial del Área de Salud de la UASB, CODEMIA y SIPAE, se inserte en el referido proyecto TEG 3. Objetivos específicos a) Análisis histórico de tensiones y conflictos sobre el acceso al agua y el canal de riego. b) Establecer patrones de consumo de agua, según tipologías de sistemas de producción presentes en el Sistema de riego Tabacundo c) Tipologizar los patrones de deterioro de la calidad del agua en el referido sistema de riego d) Indagar sobre las implicaciones que tienen para la producción familiar, el ambiente y la salud de las familias que viven en las comunidades del área de influencia de ese sistema de riego, los patrones de consumo y de deterioro del agua e) A partir de las conclusiones del estudio, formular, de modo participativo, una propuesta de nueva normativa municipal (del cantón Pedro Moncayo), respecto a la relación agua, producción, ambiente y salud, para la materialización local de los derechos colectivos al agua, la salud y ambiente saludable. f) Formar un núcleo de investigadores comunitarios, orgánicamente articulados a CODEMIA. Actividades Objetivos específicos Implicaciones concretas / actividades Estudio de la historia del agua -­‐
como tema social y ecológico en la zona del canal y el papel de -­‐
CODEMIA en esa historia. Establecer patrones de consumo de agua, según tipologías de sistemas de producción presentes en el Sistema de riego Tabacundo -­‐
Tipologizar los patrones de deterioro de la calidad del agua en el referido sistema de riego -­‐
-­‐
-­‐
-­‐
Indagar sobre las implicaciones que tienen para la producción familiar, el ambiente y la salud de las familias que viven en las comunidades del área de influencia de ese sistema de riego; así como los patrones de consumo y de deterioro del agua g) A partir de las conclusiones del estudio, formular, de modo participativo, una propuesta de nueva -­‐
-­‐
-­‐
-­‐
-­‐
-­‐
Periodización sobre el dominio del agua Construcción de los sujetos sociales involucrados y sus intereses estratégicos actuales Caracterización de los sistemas de producción Análisis del reparto de los derechos de agua Determinación de uso volúmenes de agua según tipo de cultivos Análisis de la calidad del agua aplicada o residual según sistemas de producción Análisis de la situación ambiental del agua de mantos freáticos, quebradas y ríos Aplicaciones tecnológicas / y de técnicas de investigación Láminas de riego Análisis físico, químico y biológico de las aguas en laboratorio Análisis de los patrones de alimentación local Entrevistas, Análisis comparativo de aplicación de historiales de salud en la encuestas, zona procesamiento de Análisis de las reportes de modificaciones paisajísticas dependencias y ambientales locales del MSP Análisis comparativo de fotografía aérea e histórica Análisis de normativa local Elaboración de una vigente matriz para análisis Acopio de insumos para de normativa local nueva normativa local vigente y normativa municipal (del -­‐
cantón Pedro Moncayo), respecto a la relación agua, -­‐
producción, ambiente y salud, para la -­‐
materialización local de los derechos colectivos al agua, la salud y ambiente saludable. Formar un núcleo de investigadores comunitarios, orgánicamente articulados a CODEMIA -­‐
-­‐
-­‐
Organización de insumos y formulación de propuesta Eventos participativos de análisis de nueva propuesta Elaboración de propuesta de nueva normativa local Designación por parte de CODEMIA de un núcleo de jóvenes para iniciar proceso de investigación Procesos de formación de investigadores a través de eventos presenciales (conceptuales y metodológicos) y, de aplicación práctica de esos elementos Evaluación y certificación de los investigadores comunitarios formulación de nueva normativa Elaboración de cartillas de formación de investigadores comunitarios en agua, sistemas de producción, salud y ambiente Taller de agua y de metales pesados
En el primer taller se trabajó con casi 200 variables de pruebas de calidad del
agua, utilizando un equipo portátil de alta tecnología que adquirió
recientemente nuestro programa.
El segundo taller está relacionado con un laboratorio de alta tecnología para
metales pesados. Esto es muy importante para las tesis y nuestro programa de
investigación.
En los dos talleres participaron los estudiantes del Doctorado en Salud,
Ambiente y Sociedad, cuyos proyectos de investigación están relacionados con
el análisis de metales pesados y el agua en la región amazónica y la región
costera del Ecuador. Contó con la colaboración de Víctor Gatica, técnico
chileno, experto en el análisis de metales pesados; y Orlando Felicita, técnico
ecuatoriano y que forma parte del equipo de expertos en el análisis HACH de
agua.
Para consolidar nuestro trabajo hemos implementado experiencias de campo
en Tabacundo, una zona florícola y agroindustrial del Norte Andino de nuestro
país. La idea fue observar las condiciones sociales y ecológicas de la zona y
definir los sitios de muestreo en los canales de agua. También se tomaron las
muestras que luego fueron analizadas en los correspondientes talleres de
calidad de agua y metales pesados. Esta actividad no sólo fue importante para
las prácticas de formación, sino que hace parte de un esfuerzo conjunto de la
UASB y el Consorcio de Desarrollo de Manejo Integral de Agua y Ambiente
(CODEMIA), que opera en la región, para proponer soluciones al deterioro del
agua de riego.
El lunes 16 de julio, con ayuda del laboratorio portable para análisis de agua y
metales pesados, se tomaron 11 muestras de agua a lo largo del canal de riego
de Tabacundo para su posterior análisis.
CODIGO
COORDENADAS
MSNM
DESCRIPCION
CONTAMINANTES
P1CAPTA
E836281
N10009035
3840
Captación quebrada
Angurreal, 50 litros x
segundo.
Capta agua del
Cayambe. Hay
ganado y
contaminación
biológica.
P2CAPTB
E835972
N10007348
3950
P3CAPTC
E831687
N10013549
3300
Captación quebrada
Chimborazo, 70 litros x
segundo.
Captación de Guanes,
definitiva, 464 litros
segundo.
P4MUYURCO
E822028
N10012143
3200
Acequia en Comunidad
de Muyurco, km 14 de la
acequia.
Dos quebradas que
se unen a Rio
Terrera; todavía no
hay presencia de
químicos. Hacia
abajo empieza
ganadería de leche
y algo de papa,
habas, quinua.
Zona lechera;
también hay
cultivos de papas,
habas, quinua.
P5AYORATUPIGA
CHI
E814334
N10013861
3000
Junto a comunidad de
San Isidro, km 35 de la
acequia; límite de
Tupigachi y Ayora, junto
a la Panamericana.
Junto a comunidad de
San Juan Loma en
límite de Tupigachi y
Tabacundo, km 49 de la
acequia.
Junto a desarenador,
km 60 de acequia.
P6CHAUPILOMA
E811966
N10009838
2950
P7QUEBRADAHON
DA
E807188
N1005891
2800
P8TOMALON
E805604
N10003358
2
2800
Junto a Comunidad
Tomalón, km 65 de
acequia en
Panamericana Norte.
P10CAPCHIMBOR
AZO
E835952
N10007339
4000
Captación agua potable
CODEMIA 20 litros x
segundo.
Zona de agricultura
pastos, maíz,
papas, quinua.
Zona donde
empiezan las
florícolas.
Límite de
Tabacundo y la
Esperanza en zona
florícola fuerte.
Poca presencia de
florícolas;
agricultura de
subsistencia y
agroecología.
Poco ganado
Durante el desarrollo de los proyectos, hemos podido incorporar nuevos
apoyos institucionales para los talleres y seminarios que han permitido
fortalecer y ampliar la participación de diferentes actores a los originalmente
propuestos.
Los fondos semilla han demostrado ser fundamentales en el
desencadenamiento de las actividades de observación de campo, básico para
las tesis de doctorado. Y también los talleres y los resultados de los seminarios
claramente han superado nuestros objetivos y contribuyeron a la temprana
consolidación de buenas relaciones con la comunidad y representantes de
instituciones públicas. También las actividades proporcionan una excelente
plataforma para la obtención de cooperación técnica internacional adicional.
Universidad Andina Simón Bolívar
Área de Salud
Protocolos de medición de metales pesados
Material Taller Análisis de metales pesados
con Víctor Gatica, técnico chileno
Julio 2012
MODERNWATER
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AN
Application Note
Document No.:
AN045
Version No.:
04
Effective Date:
1 Aug 2011
Low Level Mercury at a Thin Gold Film -
PDV6000p{us
page 1 of 5
Standard
Comparison
Method for water samples - PDV6000p{us
This application note describes the analysis of water samples for Mercury (Hg)
using the PDV6000plus connected to a PC running the VAS software.
It uses a thin gold (Au) film plated eledrode and the linear sweep mode.
SUMMARY:
The method described is the Standard Comparison (SC) technique which is suitable for
samples that have a low organic content, such as clean river, lake and sea water.
Organics will bind to metals and may limit or prevent detection.
For samples of wastewater, effluent and natural waters with, a significant organic content,
results will need to be checked using the standard addition method, as described in the
instrument manuals. Very dirty samples may require digestion of the matrix before analysis
can be carried out. See Note 8, below.
ANALYSIS: The PDV6000plus can be used as a standalone instrument
screening analysis however this application is not recommended for standalone use.
STANDALONE
for
LOWER DETECTION LlMIT: 0.1 ppb (100 ppt) in the analysis cell using the instrument
connected to a PC running VAS software.
REPRODUCIBILITY:
Coefficient bf variation of <5% over 5 analyses at 5 ppb in solution.
KNOWN INTERFERENCES: Silver (Ag) at concentrations equal to or higher than the Hg
concentration. Copper (Cu) will enhance the Hg peak when the concentration is 10x greater
than that of Hg. High chloride (CI-) content may cause peak to shift to more negative potentials
PEAK POTENTIAL:
REAGENTS:
Electrolyte
Standard:
Plating Solution:
Other Reagents:
400 mV to 650 mV vs. Ag/ AgCI. This might vary depending on conditions.
Mercury Acid Electrolyte (pn R-300-500EHG-02)
Mercury Standard (20 ppm, pn R-300-20STHG-01)
Gold Plating Solution (pn R-300-025PLA-AU)
Electrode Conditioning Solution A (pn R-300-025ECS-01)
Ultrapure water (> 18MQ)
Note:
Dedicated electrode sets are recommended for different types of analysis, as voltammetry is a
very sensitive technique.
Contamination can cause the application not to work at all.
SOIL ANAL YSIS:
This method has not yet been validated with soil samples.
Uncontrolled copy unless stamped 'Controlled' or viewed as pdf.
If this is an uncontrolled CODV, verifv the revision is current before use.
MODERNWATER
rT1
Cogentw
AN
Application Note
Document No.:
AN045
Version No.:
04
Effective Date:
1 Aug 2011
Low Level Mercury at a Thin Gold Film - PDV6000p{us
page 2 of 5
RUN CONFIGURATION:
Figure 1: run configuration for Mercury
The Ruh Configuration shown aboye is suitable for sample concentration range of .
0.1-0.5 ppb (see Table 1 below). For sample concentrations outside this range it may be
necessary to alter the Deposit Time and Range Setting. A Sweep Rate of 1000mV/s can be
used for higher concentrations.
Deposit time and the current range are variable parameters, dependent on the metal
concentration of the sample. Use Table 1 below to select the deposit time and current range
setting for the expected sample concentration range:
Sample
Concentration
Range (ppb)
0.1 - 0.5
0.5 - 2
2 - 5
5 - 10
Standard
Concentration
(ppb)
0.2
1
4
8
DepositTime
(seconds)
Range Setting
(IJA)
."
600
300
180
120
30
100
300
300
Table 1: Suggested standard concentration, deposit time and current range setting to use
depending on the actual sample concentration range.
Note: The recommended standard concentration, deposit time and current range setting to
measure an expected sample concentration, as listed in Table 1, are suggested starting values.
These have been extrapolated from experience with the PDV6000 and PDV6000plus, with a
range of electrode sensitivities.
Best values will depend on specific electrode characteristics. The operator should adjust the
values according to experience, Ideally, for most accurate results, the concentration of the
standard should be as close as possible to the concentration of the actual sample. The current
range setting should be selected to allow sufficient headroom so that a possible sample peak
does not go over range.
Uncontrolled copy unless stamped 'Contro/led' or viewed as pdf.
If this is an uncontrolled CODV, verifv the revision ís current before use.
)
MODERNWATER
Cogent
m
L'~!.;J
AN
Application Note
Document No.:
AN045
Version No.:
04
Effedive Date:
1 Aug 2011
Low Level Mercury at a Thin Gold Film - PDV6000p{us
Page 3 of 5
ANALYTICAL
PROCEDURE:
The details described below can be found in the PDV6000plus Operation Manual (Section 5.3).
Electrode Conditioning and Plating
1. Clean the Glassy Carbon Electrode by polishing the Carbpn surface with the supplied
Polishing Kit. Rinse residual polishing fluid off the eledrode with ultrapure water.
2. Dip the electrode in Electrode Conditioning Solution A for at least 20 seconds, rinse the
electrode with ultrapure water, return the eledrode to the analysis cell and reconnect the
electrode.
3. Rinse the cell. Fill a clean analysis cup with 20 mL of ultrapure water, place in the cell
assembly and rinse the cell.
4. Into a clean an,alysis cup add 25 mL of the Gold Plating Solution. Plate a thin gold film onto
the Glassy Carbon Electrode, using a plate potential of -500 mV for 300seconds. The rest
potential should be set as 700 mV. The plating solution can be used upto 5 times.
5. Fill a clean analysis cup with 20 mi of ultrapure water, place in the cell assemb!y and rinse
the cell. Repeat 3-5 times.
Run Blank
6. Take a clean analysis cupo Inject 10 mL of the electrolyte and 10 mL ultrapure water. Place
the cup in the cell assembly. Analyse this solution as a blank using the Run Configuration,
Figure 1, and Table 1. Select a deposit timeand range setting depending on the sample
concentration.
Run Standard
7. Inject into the cell an appropriate amount of Mercury Standard (see Table 1). Analyse this
solution several times until the reproducibility is acceptable (within 5%).
8. Rinse the cell several times as described aboye in step 3.
Run Sample
9. Take a clean analysis cup and inject 10 mL of the electrolyte and up to 10 mL sample
solution making up the volume to 20 mL with ultrapure water. Analyse this sarriple solution
using the same parameters as used for the standard. Typically up to 5 samples can be
analysed per standard calibration.
Uncontrolled copy unless stamped 'Controlled' or viewed as pdf.
If this is an uncontrolled CODV, verifv the revision is current before use.
m
Cogent l~J
MODERNWATER
AN
Application
Document
Version
Note
No.:
No.:
Effective
AN045
04
Date:
1 Aug 2011
Low Level Mercury at a Thin Gold Film - PDV6000p[us
Page 4 of 5
Figure 2: Mercury peaks - 5 ppb (grey trace) and 2.5 ppb (blue trace)
with a deposit time of 180 seconds.
using blank subtraction,
Figure 3: Mercury peak - 100 ppt (0.1 ppb) using Blank Subtraction
deposit time and 2000 mVjs Sweep rate
with a 600 second
NOTES:
1. Low level mercury standards «lppm)
are unstable.
a stock solution. Make in a 5% nitric acid solution.
2. The use of blank subtraction
They should
is always useful and essential
be made fresh daily from
when determining
low levels.
Uncontrolled copy unless stamped 'Contro/led' or viewed as pdf.
If this is an uncontrolled CODV, verifv the revisíon ís current before use.
AN
Application Note
Document No.:
AN045
Version No.:
04
Effective Date:
1 Aug 2011
Low Level Mercury at a Thin Gold Film - PDV6000p{us
Page 5 of 5
3. If measuring very low levels (ppt), it is advisable to analyse standards of a higher
concentration initially (5 ppb in the cell) and then analyse those at the expected level, to
help condition the electrode.
4. It is possible to measure down to 10 ppt with a deposit time of 20 minutes (1200 seconds).
5. If no response is seen with the standard or if the standard response has diminished, replate the electrode (see Electrode conditíoning and platíng section).
6. Leave the electrodes in a cup of UltraPure water when not in use. Do not leave the cell
empty for an extended period of time, as this will result in oxidation and damage to the film.
Do not leave the film electrode in electrolyte for an extended period of time.
7. For accurate results, the calibration step must be carried out as close to the expected or
most significant (alarm level etc) sample concentration. The maximum linear range that can
be expected if the instrument is running well is from one tenth of the standard peak height
to double the standard peak height. For high results re-run the sample so that its peaks are
in this range (e.g. 10 mi electrolyte, 9 mi water and 1 mi sample if you need to dilute the
sample x10).
8. For samples of wastewater, effluent or samples with organic content, results will need to be
checked using the standard addition method, 'as describedin the instrument manuals.
Standard Addition' (SA) analysis involves running the sample followed by subsequent
analyses afte!' the addition of known amounts of standard.
The result is calculated from a linear regression analysis, and the resulting correlation'
coefficient reveals the linearity of the measurement (correlation must be >0.995). The
Standard Addition resúlts are assumed to be the correct results if the correlation is >0.995 .
.'
If the standard addition (SA) result is more that 25% from the standard comparison (SC)
result, there is a matrix effect presento Either sample digestion or standard addition is
needed. If the standard addition gives no peak or a very small peak, extra digestion is
required.
The simplest form of digest is done by adding some acid. Heating and UV radiation are
other techniques that can be used.
Uncontrolled copy unless stamped 'Controlled' or viewed as pdf.
If this is an uncontrolled CODV, verifv the revision is current before use.
"
.':¡
MODERNWATER
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AN
Application Note
Document No.:
AN044
Version No.:
04
Effective Date:
1 Aug 2011
Mercury on a Gold Film Electrode - PDV6000p{us
Page 1 of 5
Standard
Comparison
Method for water
samples - PDV6000p{us
This application note describes the analysis of water samples for Mercury (Hg)
using the PDV6000plus connected to a PC running the VAS software.
It uses a thin gold film plated electrode and the linear sweep mode.
SUMMARY:
The method described is the Standard Comparison (SC) technique which is suitable for
samples that have a low organic content, sueh as clean river, lake and sea water.
Organics will bind to metals and may limit or prevent detection.
For samples of wastewater, effluent and natural waters with a significant organic content,
results will need to be checked using the standard addition method, as described in the
instrument manuals. Very dirty samples may require digestion of the matrix before analysis
can be carried out. See Note 6.
ANALYSIS: The PDV6000plus can be used as a standalone instrument for
screening analysis. With the VAS software, greater accuracy and reliability can be achiev~d..We .
recommend that examples are analysed first with VAS, to check the sample preparation', .etc.'
before the standalone is used. Refer to the instrument manual for details of the standalone
operations
STANDALONE
5 ppb in the analysis cell using the instrument connected tO¡a;PC .
running VAS software.
; ;.
(For a lower detection limit of 0.1 ppb (100 ppt) in the analysis cell, see Application IVQte ¡'
AN045: Low level Mercury on a Gold Film Carbon Electrode.)
LOWER DETECTION 'LIMIT:
REPRODUCIBILITY:
Coefficient of variation of <5% over 5 analyses at 5 ppb in solution.
KNOWN INTERFERENCES: Silver (Ag) at concentrations equal to or higher than the mercury
concentration. Copper (Cu) will enhance the mercury peak when the concentration is :18x
greater than that of mercury. High chloride (CI-) content may cause the mercury peak to shift
to more negative potentials.
PEAK POTENTIAL:
REAGENTS:
Electrolyte
Standard:
Plating Solution:
Other Reagents:
450 mV to 700 mV vs. Ag/AgCI. This might vary depending on conditions.
Mercury Acid Electrolyte (pn R-300-500EHG-02)
Mercury Standard (20 ppm, pn R-300-20STHG-01)
Gold Plating Solution (pn R-300-025PLA-AU)
Electrode Conditioning Solution A (pn R-300-025ECS-01)
Ultrapure water (> 18MQ)
Note:
Dedicated electrode sets are recommended for different types of analysis, as voltammetry is a
very sensitive technique.
Contamination can cause the application not to work at all.
SOIL ANAL YSIS:
This method has not yet been validated with soil samples.
Uncontrolled copy unless stamped 'Controlled' or víewed as pdf.
If this is an uncontrolled CODV, verífv the revision is current before use.
;·;~.i
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MODERNWATER
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m
A'N
Document No.:
AN044
lA)
Application Note
Version No.:
Effective Date:
04
1 Aug 2011
Mercury on a Gold Film Electrode
PDV6000p{us
Page 2 of 5
RUN CONFIGURATION:
Figure 1: Run configuration
for mercury
Deposit time and the current range are variable parameters, dependent on the metal
concentration of the sample. Use Table 1 below to select the deposit time and current
range setting for the expected sample concentration range. A Sweep Rate of 1000mV/s can
be used for higher concentrations.
Sample Concentration
Range (ppb)
0.1-5
6-10
11-50
51-100
101-200 +
Standard
Concentration (ppb)
Deposit Time
(seconds)
Range
Setting (µA)
See AN045 Low level Mercurv on a Gold Film Electrode
100
8
180
300
30
120
300
80
60
150
30
300
Table 1: Suggested standard concentration, deposit time and current range setting to use
dependirig on the actual sample concentration range.
Note: The recommended standard concentration, deposit time and current range setting to
measure an expected sample concentration, as listed in Table 1, are suggested starting values.
These have been extrapolated from experience with the PDV6000 and PDV6000plus, with a
range of electrode sensitivities.
Best values will depend on specific electrode characteristics. The operator should adjust the
values according to experience. Ideally, for most accurate results, the concentration of the
standard should be as close as possible to the concentration of the actual sample. The current
range setting should be selected to allow sufficient headroom so that a possible sample peak
does not go over range.
Uncontrolled copy unless stamped 'Controlled' or viewed as pdf.
If this is an uncontrolled CODV, verifv the revision is current before use.
,
MODERNWATER
Cogent
m
l~l,J
AN
Application Note
Document No.:
AN044
Version No.:
04
Effective Date:
1 Aug 2011
Mercury on a Gold Film Electrode - PDV6000p{us
page 3 of 5
ANALYTICAL PROCEDURE:
The details described below can be found in the PDV6000plus Operation Manual (Section 5.3).
Electrode Conditioning and Plating
1. Clean the Glassy Carbon Electrode by polishing the Carbon surface with the supplied
Polishing Kit. Rinse residual polishing fluid off the electrode with ultrapure water.
2. Dip the electrode in Electrode Conditioning Solutíon A for .at least 20 seconds, rinse the
electrode with ultrapure water, return the electrode to the analysis cell and reconnect the
electrode.
3. Rinse the cell. Fill a clean analysis cup with 20 mL of ultrapure water, place in the cell
assembly and rinse the ce".
4. Into a clean analysis cup add 25 mL of Gold Plating Solution. Plate a thin gold film onto the
Glassy Carbon Electrode using a plate potential of -500mV, for 300 seconds. The rest
potential should be set as 700 mV. The plating solution can be used upto 5 times.
;
,
5. Fill a clean analysis cup with 20 mlof tJltrapure water, place in the cell assembly and rinse
the ce". Repeat 3-5 times.
Run Blank
6. Take a clean analysis cupo Inject 10 mL of the electrolyte and 10 mL ultrapure water. Place
the cup in the cell assembly. Analyse this solution as a blank using the Run Configuration
shown in Figure 1, and Table 1. Select a deposit time and range setting dependi ng on the
sample concentration.
Run Standard
7. Inject into the cell an appropriate amount of Mercury Standard (see Table 1). Analyse this
solution several times until the reproducibility is acceptable (within 5%).
8. Rinse the ce" as described in step 5 aboye.
Run Sample
9. Take a clean analysis cup and inject 10 mL of the electrolyte and 10 mL sample. Analyse
this solution using the same parameters as used for the standard. Up to 5 samples can be
analysed per standard calibration.
Uncontrolled copy unless stamped 'Controlled' or viewed as pdf.
If this is an uncontrolled CODV, verifv the revision is current before use.
MODERNWATER
Cogent
m
llJJ
Document
AN
Application
Note
No. :
\
AN044
\
Version No.:
04
Effective
1 Aug 2011
Date:
Mercury on a Gold Film Electrode - PDV6000p{us
Figure 2: Mercury peaks - 100 ppb (grey trace) with a 60 second Deposit Time, and 5 ppb
(blue trace). Deposit Time 180 seconds.
NOTES:
1. The use of blank subtraction
is always useful and essential when determining
low levels.
2. For accurate results, the calibration
most significant
can be expected
height to double
peaks are in this
dilute the sample
step must be carried out as close to the expected or
(alarm level etc) sample concentration.
The maximum linear range that
if the instrument is running well is from one tenth of the standard peak
the standard peak height. For high results re-run the sample so that its
range (e.g. 10 mL electrolyte, 9 mL water and 1 mi sample if you need to
x10).
3. For high concentration analysis (>200 ppb in the cell), incr~asing the Clean Time in the
Run Configuration to 30 seconds is recommended. This will ensure that all elements are
removed
samples.
from
the film surface
after
each run, to prevent
contamination
of subsequent
4. If no response is seen with the standard or if the standard response has diminished,
plate the electrode (see Electrode conditioning and plating section).
re-
5. Leave the electrodes
in a cup of ultrapure water when not in use.
Do not leave the cell
empty for an extended period of time, as this will result in oxidation and damage to the
film. Do not leave the film electrode in electrolyte for an extended period of time.
6. For samples of wastewater,
effluent or samples with organic content, results will need to be
checked using the standard addition method, as described in the instrument
manuals.
Standard Addition (SA) analysis involves running the sample followed by subsequent
analyses after the addition of known amounts of standard.
The result is calculated from a linear regression analysis, and the resulting correlation
coefficient reveals the linearity of the measurement
(correlation
must be >0.995). The
Standard Addition results are assumed to be the correct results if the correlation is >0.995.
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Mercury on a Gold Film Electrode - PDV6000p{us
Page 5 of 5
If the standard addition (SA) result is more that 25% from the standard comparison (Se)
result, there is a matrix effect presento Either sample digestion or standard addition is
needed. If the standard addition gives no peak or a very small peak, extra digestion is
required.
The simplest form of digest is done by adding
other techniques that can be used.
some acid. Heating
and UV radiation
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AN028
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Version No.:
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Date:
Cadmium, Lead & Copper at Thin Mercury Film - PDV6000p{us
Page 1 of 5
Standard
comparison
method for water analysis - PDV6000p[us
SUMMARY: This application note describes the analysis of water samples for Cadmium (Cd),
Lead (Pb) and Copper (Cu) using the PDV6000plus
connected to a PC running the VAS
software.
It uses a thin Mercury (Hg) film plated eledrode and the linear sweep mode.
The method described is the Standard Comparison
(SC) technique which is suitable for
samples that have a low organic content, such as clean river, lake and sea water.
Organics will bind to metals and may limit or prevent detection.
For samples of wastewater,
effluent and natural waters with a significant
organic content,
results will need to be checked using the standard addition method, as described in the
instrument manuals. Very dirty samples may require digestion of the matrix before analysis
can be carried out. See Note 7, below.
STANDALONE
ANALYSIS:
The PDV6000plus
can be used as a standalone
instrument
for
screening analysis. However the standalone can only analyse for one metal at a time. With the
VAS software greater accuracy and realiability can be achieved. We recommend that examples
are analysed first with VAS to check the sample preparation etc befo re the standalone is used.
Refer to the instrument manual for details of the standalone operations.
LOWER DETECTION LIMIT:
PC running VAS software.
REPRODUCIBILITY:
0.5 ppb in the analysis cell using the instrument
Co-efficient
of Variation
connected
to a
<5% over 5 analyses at 100 ppb in solution.
KNOWN INTERFERENCES:
Thallium (TI), zinc (Zn), and bismuth (Bi) can cause interferences.
TI due to peak overlap, forming a peak at approximately
-600 mV, Zn and Bi by forming an
inter-metallic
compound with copper.
PEAK POTENTIAL:
Cd:
Pb:
Cu:
These may vary depending
on conditions.
-800 mV to -500 mV vs. Ag/AgCI
-550 mV to -300 mV vs. Ag/AgCI
-350 mV to -50 mV vs. Ag/AgCI
REAGENTS:
Electrolyte
Standard:
Plating Solution:
CLAC electrolyte.
(Dissolve 1xCLAC Electrolyte Concentrate
(pn R-300-500CLA-01)
Electrolyte Difuent A (pn R-300-500ELD-01)
or Ultrapure Water>
Cd, Pb, Cu Standard (20 ppm, pn R-300-20STAA-01)
Mercury Plating Solution (pn R-300-025PLA-HG)
Other Reagents:
Electrode
Conditioning
Solution
into
18MQ)
A (pn R-300-025ECS-01)
Note: Dedicated
electrode
sets are recommended
for
voltammetry
is a very sensitivetechnique.
Contamination can cause the application not to work at all.
SOIL ANAL YSIS:
The PDV6000plus can be used to analyse for cadmium
customer services for details.
different
and lead in soils.
Uncontrofled copy unless stamped 'Controfled'
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CODV, verifv the revision
types
of
analysis,
Please contact our
or viewed as pdf.
is current before use.
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Note
Cadmium, Lead & Copper at Thin Mercury Film
PDV6000p{us
page 2 of 5
RUN CONFIGURATION:
Figure 1: Run Configuration
for Cadmium, Lead and Copper
Deposit time and the current range are variable parameters, dependent on the metal
concentration of the sample. Use Table 1 below to select the deposit time and current range
setting for the expected sample concentration range:
Sample
Concentration
RanQe (ppb)
Standard
Concentration
(ppb)
Deposit
Time
(seconds)
Range Setting
(IJA)
5-20
10
180
30
20-100
50
60
100
100-500
200
40
300
400-800
800
10
1 mA
rabie 1: Suggested standard concentration,
the actual sample concentration range.
deposit time and current range setting to use depending on
Note: The recommended standard concentration,
deposit time and current range setting to
measure an expected sample concentration, as listed in Table 1, are suggested starting values.
These have been extrapolated from experience with the PDV6000 and PDV6000plus, with a
range of electrode sensitivities.
Best values will depend on specific electrode characteristics.
The operator should adjust the
values according to experience. Ideally, for most accurate results, the concentration
of the
standard should be as close as possible to the concentration of the actual sample. The current
range setting should be selected ,to allow sufficient headroom so that a' possible sample peak
does not go over range.
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Cadmium, Lead & Copper at Thin Mercury Film - PDV6000p{us
page 3 of 5
ANAL YTICAL PROCEDURE:
These details can also be found in the PDV6000plus Operation Manual (Section 5.3).
Electrode Conditioning and Plating
1. Clean the Glassy Carbon Electrode by polishing the carbon surface with the supplied
Polishing Kit. Rinse residual polishing fluid off the electrode with ultrapure water.
2. Dip the electrode in Electrode Conditioning Solution A for at least 20 seconds, rinse the
electrode with ultrapure water, return the electrode to the analysis cell and reconnect the
electrode.
3. Rinse the cell. Fill a clean analysis cup with 20 mL of ultrapure water, place in the cell
assembly and rinse the cell.
4. Fill a clean analysis cup with 25 mL of Mercury Plating Solution. Plate a thin mercury film
onto the Glassy Carbon Electrode using a plate potential of -1300 mV for 300 seconds, the
rest potential should be set to -100 mV. The plating solution can be used upto 5 times.
5. Fill a clean analysis cup with 20 mL of ultrapure water, place in the cell assembly and rinse
the cell. Repeat 3-5 times.
Run Blank
6. Take a clean analysis cupo Inject 10.0 mL of CLAC electrolyte and 10 mL ultrapure water.
Place cup in cell assembly. Analy"se this solution as a blank using the Run Configuration,
Figure 1, and Table 1. Select a deposit time and range setting depending on the expected
sample concentration.
Run Standard
7. Inject into the ce" an appropriate amount of Cd, Pb, Cu Standard (see Table 1). Analyse this
solution several times until the reproducibility is acceptable (within 5%).
8. Rinse the cell as described in step 5 aboye.
Run Sample
9. Take a clean analysis cup and inject 10 mL CLAC electrolyte and 10 mL sample. Analyse this
solution using the same parameters as used for the standard. Up to 5 samples can be
analysed per standard calibration.
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AN028
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Effective Date:
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Cadmium, Lead & Copper at Thin Mercury Film - PDV6000p{us
Page 4 of 5
Figure 2: Cadmium, Lead and Copper peaks - 10ppb (black trace) and 20 ppb (blue
trace) in the Cell. Deposit Time 60 seconds.
NOTES:
1. If the sample has a high concentration of zinc, it will be difficult to measure copper, as zinc
will interfere by forming an intermetallic compound with the copper and increasing the size
of the copper peak. To overcome this interference the deposition potential must be reduced
to -450mV, therefore measuring copper without cadmium and lead and preventing the
deposition of zinc.
2. For accurate results, the calibration step must be carried out as close to the expected or
most significant (alarm level etc) sample concentration. The maximum linear range that
can be expected if the instrument is running wel! is from one tenth of the standard peak
height to double the standard peak height. For high results re-run the sample so that its
peaks are in this range (e.g. 10 mL electrolyte, 9 mL water and 1 mi sample if you need to
dilute the sample x10).
3. If no response is seen with the standard or if the standard response has diminished, replate the electrode (see Electrode conditioning and plating section).
4. For high concentration analysis (>200 ppb in the cell), increasing the Clean Time to 30
seconds in the Run Configuration is recommended, to ensure that al! elements are removed
from the film surface after each runo This will help to prevent contamination of subsequent
samples.
5. Leave the electrodes in a cup of ultrapure water when not in use. Do not leave the cel!
empty for an extended period of time, as this will result in oxidation and damage to the
film. Do not leave the film electrode in a media such as CLAC electrolyte for an extended
period of time, as this may result in an interaction between the CLACand the film.
Uncontrolled copy unless stamped 'Controlled' or viewed as pdf.
If this is an uncontrolled CODV, verifv the revision is current before use.
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Application Note
Document No.:
AN028
Version No.:
04
Effective Date:
1 Aug 2011
Cadmium, Lead & Copper at Thin Mercury Film - PDV6000p{us
page 5 of 5
6. For very low sample concentrations in clean samples, 18 mL of sample may be analysed
with 2 mL concentrated CLAC electrolyte. Concentrated CLAC is made by adding 1x
electrolyte concentrate to 50 mL Electrolyte Diluent A instead of 500 mL.
7. For samples of wastewater, effluent or samples with organic content, results will need to be
checked using the standard addition method, as described in the instrument manuals.
Standard Addition (SA) analysis involves running the sample followed by subsequent
analyses after the addition of known amounts of standard.
The result is calculated from a linear regression analysis, and the resulting correlation
coefficient reveals the linearity of the measurement (corr'elation must be >0.995). The
Standard Addition results are assumed to be the correct results if the correlation is >0.995.
If the standard addition (SA) result is more that 25% from the standard comparison (SC)
result, there is a matrix effect presento Either sample digestion or standard addition is
needed. If the standard addition gives, no peak or a very small peak, extra digestion is
required.
The simplest form of digest is done by adding some acid. Heating and UV radiation are
other techniques that can be used.
Uncontrol/ed copy unless stamped 'Control/ed' or viewed as pdf.
If this is an uncontrolled CODV. verifv the revision is current before use.