Implementation Manual
for the 16th Inter-laboratory Comparison Project on Inland Aquatic Environment
2015
1. Purpose
This inter-laboratory comparison project (round robin analysis of uniformly prepared
artificial inland water sample) will be conducted among the analytical laboratories in
the EANET, based on the Quality Assurance / Quality Control (QA/QC) program.
The purpose of this project is through the evaluation of analytical results, analytical
equipment and its operating condition and other practical problems, i) to recognize
the analytical precision and accuracy of each participating laboratory, and give an
opportunity to improve the quality of the analysis on inland water monitoring, and ii)
to improve reliability of analytical data through the assessment of suitable analytical
methods and techniques.
2. Method
(1) Participating laboratories
Laboratories in charge of chemical analysis for monitoring on inland aquatic
environment of the participating countries of the EANET.
(2) Activities
An artificial inland water sample (hereafter “sample”) is distributed to the above
mentioned laboratories. The information on the analytical precision and accuracy on
individual parameters can be obtained through the statistical treatment of submitted
analytical data of sample.
(3) Analytical Parameters
All participating laboratories should measure and submit the data on eleven
parameters of the sample : pH, electric conductivity, alkalinity and concentration of
chloride, nitrate, sulfate, ammonium, calcium-ion, magnesium-ion, potassium-ion,
and sodium-ion.
1
3. Outline of sample
Name
Table 1. Outline of artificial surface water sample
Amount of the Container
Serial Number Note
sample
of sample
Approximately Poly-ethylene Two bottles *
To analyze
1000ml
bottle 1000ml
directly
Artificial inland
water sample
Sample No.151i
*：One of two bottles is for using as the reference material after disclosing
expected value.
pH, EC, alkalinity and concentration of ions are expected to be within the
range described in the next Table 2.
Table 2. Concentration range of the artificial surface water sample
Parameter
Range
Parameter
Range
pH
5.0 – 8.0
NH4+
0.05 – 0.5 mg/L
EC
1.5 – 15 mS/m
Ca2+
0.5 – 5 mg/L
Alkalinity
0.05 – 0.5meq/L
Mg2+
0.2 – 2 mg/L
+
Cl
1 – 10 mg/L
K
0.2 – 2 mg/L
NO30.5 – 5mg/L
Na+
1 – 10 mg/L
2SO4
2 – 20 mg/L
4. Preparation of sample, and analytical method
(1) Sample treatment
Sample should be measured directly without dilution. Keep the samples in a
cool and dark place such as a refrigerator after arrival. Chemical analysis of
the samples should be carried by the end of 2015. Special attention should be
paid to analysis of the samples because the quality of the sample could be changed
gradually by absorbing carbon dioxide from the air. The samples should be analyzed
immediately. Don’t keep the sample bottle open for hours. If the measurement
can’t be carried out immediately after the arrival of sample, the sample should
be stored in a cool and dark place such as a refrigerator immediately after
receiving.
(2) Analytical method
It is recommended to keep the water temperature at about 25°C using a water bath
during the measurement of pH and EC. If temperature controlled water bath is not
available, use of water bath without temperature control but containing at least 5 L
of water may be considered.
2
It is desirable to analyze the sample as soon as possible, and don't leave it for long
time while opening the lid of the sample vessel. Use analytical methods and data
checking procedures that are specified in the “Technical Manual for Monitoring on
Inland Aquatic Environment in East Asia (hereafter the manual)” and “Quality
Assurance / Quality Control (QA/QC) program for Monitoring on Inland Aquatic
Environment in East Asia” for the EANET for this inter-laboratory comparison
project. Followings are analytical methods specified in the manual and the
QA/QC program.
Table 3
Analytical methods suggested for inland water sample
Parameters
Analytical Methods
pH
Glass electrode (preferably with the electrode of non-leak
inner cell)
EC
Conductivity Cell
Alkalinity
Titration by Burette or Digital Burette with pH Meter
( end-point pH4.8 )
NO3－, SO42－
Ion Chromatography (preferably with suppressor)
or Spectrophotometry
NH4＋
Ion Chromatography
or Spectrophotometry (Indophenol blue)
Ca2＋, Mg2＋, Na＋, K＋
Ion Chromatography
Spectrometry
Cl－
Ion Chromatography or Titration
or
Atomic
Absorption/Emission
(3) “Detection Limit” and “Lowest Determination Limit”
In the process of determining the Detection Limit and Determination Limit for the
suggested methods (Ion Chromatography, Spectrophotometry, Atomic Absorption
Spectrometry) used for the chemical analysis of ions in the samples, a standard
solution with concentration near the lowest determination limit (Std1) should be
measured 5 times. The Detection Limits and Determination Limits are calculated
from standard deviation(s) as follows:
Detection Limit = 3 s
Lowest Determination Limit = 10 s
3
5. Preparation of the report
Download the reporting format and questionnaire from the following URL
URL: http://www.acap.asia/~interlab/os/index.html
Complete the two attached files (“IAE_Report_Form” and “IAE_Questionnaire”)
considering the following issues.
(1) Reporting format [1] to [14]
1.Fill the data in the column with a color in each report
Light blue column… fill the data in column directly
Light green column…click a column and select the number from a list
2.Refer to the Sheet “ Example “ in reporting [1] to [11]
3.Fill in only the columns of “organization” , “Name” , “TEL”, “Fax” and “Serial
Number” in Report [12] because analysis data in Report [12] are automatically
filled in the columns if you fill the data in Report [1] to [11]
4.Fill the name of the person who practically analyzed the sample, in the column
of ”Personnel in charge of measurement”. In the case that several persons carried
out the analysis, fill in the name of the person who mainly carried out the
analysis.
5.Fill the experience period of inland water analysis of the person, in the column of
“Experience periods”.
6.Fill the serial number of distributed sample in the column of “Serial Number”.
7.Fill the calculated concentration of the sample with three significant figure after
rounding the forth figure number of the data in the column of “Analytical Result”.
Calculate the average value as arithmetic mean including pH.
8.Fill the date to start to analyze sample in the column of “Start date”, and fill the
date of completion of sample analysis of individual parameter in the column of
“Finish date”.
(2) Questionnaire concerning analytical conditions.
It is the file added newly in this attempt, and might give some clues to
understand dispersion of results. Fill the date of reception, opening, analysis, and
condition of preservation during each process for sample treatment. In addition,
append the copy of analysis chart of blank sample which were ordinarily used as
pure water for dilution through analysis for cations and anions.
4
6. Submission of the report
Submit the data reporting formats [1] to [14] together with the copy of calibration
curve and typical measurement chart (one for each parameter) except for pH,
EC and Alkalinity.
7. Dead line date of the report submission
29 February 2016(to be submitted to NC through
the QA/QC manager in your country)
8. Address of Report Submission
Submit the report to the Network Center through the National Center of each
participating country. Address of the Network Center is as following. Please be
aware that e-mail address was changed
Ken YAMASHITA
Tatsuyoshi SAITO
Data Management Department
Asia Center for Air Pollution Research
1182 Sowa, Nishi-ku, Niigata-shi, 950-2144 Japan
Fax: +81-25-263-0567; E-mail: datasubmit@acap.asia
5
Appendix
The calculation method of R1 and R2
A. Calculation of ion balance (R1)
1) Total anion (A) of equivalent concentration (μeq L-1) is calculated by summing the
concentration of all anions (c: μeq L-1) and alkalinity (ALK: μeq L-1). Alkalinity
considered to be corresponded to bicarbonate ions (HCO3-).
A (μeq L-1)= c(SO42-)+ c(NO3-)+ c(Cl-)+(ALK)
2) Total cation (C) equivalent concentration (μeq L-1) are calculated each concentration
of cations (C: μeq L-1).
C (μeq L-1)= 10(6-pH)+ c(NH4+)+ c(Na+)+ c(K+)+ c(Ca2+)+ c(Mg2+)
3) Calculation of ion balance (R1)
R1 = 100 × (C-A) / (C+A)
4) R1, which is calculated using the above equation, should be compared with standard
value in Table 1. When R1 is not in the range, some actions are necessary such as
re-measurement, check with standard sample or inspection of standard curve.
When the concentration(C) of ion is calculated as (mg L-1), it should be changed in
equivalent concentration(μeq L-1) as follows:
μeq L-1 = mg L-1×(1000/equivalent weight)
thus the total of anions and cations are shown as follows:
A(μeq L-1)
= {c(SO42-)/48.03 + c(NO3-)/62.01 + c(Cl-)/35.45 }×1000 + (ALK)
C(μeq L-1) = 10(6-pH) + {c(NH4+)/18.04 + c(Na+)/22.99 + c(K+)/39.10 +
c(Ca2+)/20.04 + c(Mg2+)/12.16}×1000
6
Table 1 Allowable ranges for R1 in
different concentration ranges
(C + A) μeq L-1
R1
<50
50-100
>100
±30
±15
±8
B. Comparison between calculations and measurement in electrical conductivity (R2)
1) Total electric conductivity (Λcalc) should be calculated as follows:
Λcalc (μS cm-1) = 349.7×10 3-pH +{80.0×c(SO42-)+71.4×c(NO3-)
+ 76.3×c(Cl-)+73.5×c(NH4+)+50.1×c(Na+)+73.5×c(K+)
+ 59.8×c(Ca2+)+53.0×c(Mg2+)+44.5×(ALK)}/1000
c: equivalent concentration (μeq L-1) of ions in the parenthesis, each constant value is
ionic equivalent conductivity at 25°C.(Table2) Alkalinity considered to be
corresponded to bicarbonate ions (HCO3-).
For SI unit system , convert Λcalc(μS cm-1) into Λcalc (mS m-1) following
Λcalc (mS m-1)=Λcalc(μS cm-1)×(1/10)
2) Ratio (R2) of calculations to measurements(Λmeas) in electric conductivity should
be calculated as follows:
R2 = 100 × (Λcalc -Λmeas)/(Λcalc +Λmeas)
3) R2, which is calculated using the above equation, should be compared with standard
value in Table 3. When R2 is not in the range, some actions are necessary such as
re-measurement, check with standard sample or inspection of standard curve.
7
Table 2
Ion
H+
NH4+
Ca2+
K+
Mg2+
Na+
Equivalent weight of cations, anions and ionic equivalent conductivity
Equivalent
Weight
Ionic
Equivalent
Conductivity
λ (S cm-2 eq-1)
Ion
NO3SO42ClHCO3HCOOCH3COOFBr NO2PO43Kagaku Binran, p.II-460. 3rd Ed., 1984, Maruzen, Tokyo.
1.008
18.04
20.04
39.10
12.16
22.99
349.7
73.5
59.8
73.5
53.3
50.1
Table 3
Equivalent
Weight
62.01
48.03
35.45
61.02
45.0
59.1
19.00
79.90
46.01
26.32
Allowable ranges for R2
for different concentration ranges
Λmeas(mS m-1)
R2
<0.5
0.5-3
>3
(1 mS m-1 = 10 μS cm-1 )
8
±20
±13
±9
Ionic
Equivalent
Conductivity
λ (S cm-2 eq-1)
71.5
80.0
76.3
44.5
54.6
40.9
55.5
78.1
71.8
69.0