EN 16602-70-05:2014

SLOVENSKI STANDARD
01-januar-2015
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Space product assurance - Detection of organic contamination surfaces by infrared
spectroscopy
Raumfahrtproduktsicherung - Detektion von organischen Kontaminationen auf
Oberflächen mit Infrarotspektroskopie
Assurance produit des projets spatiaux - Détection des surfaces de contamination
organique par spectroscopie infrarouge
Ta slovenski standard je istoveten z: EN 16602-70-05:2014
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 16602-70-05
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2014
ICS 49.140
English version
Space product assurance - Detection of organic contamination
surfaces by infrared spectroscopy
Assurance produit des projets spatiaux - Détection des Raumfahrtproduktsicherung - Detektion von organischen
surfaces de contamination organique par spectroscopie Kontaminationen auf Oberflächen mit Infrarotspektroskopie
infrarouge
This European Standard was approved by CEN on 20 March 2014.

CEN and CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving
this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning
such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN and CENELEC
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN and CENELEC member into its own language and notified to the CEN-CENELEC Management Centre
has the same status as the official versions.

CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia,
Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

CEN-CENELEC Management Centre:
Avenue Marnix 17, B-1000 Brussels
© 2014 CEN/CENELEC All rights of exploitation in any form and by any means reserved Ref. No. EN 16602-70-05:2014 E
worldwide for CEN national Members and for CENELEC
Members.
Table of contents
Foreword . 5
1 Scope . 7
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 9
3.1 Terms defined in other standards . 9
3.2 Terms specific to the present standard . 9
3.3 Abbreviated terms. 11
4 Principles . 13
5 Requirements . 14
5.1 Preparatory activities . 14
5.1.1 Hazard, health and safety precautions . 14
5.1.2 Facilities . 14
5.1.3 Materials . 15
5.1.4 Handling . 15
5.1.5 Equipment . 15
5.1.6 Miscellaneous items . 16
5.2 Procedure for sampling and analysis . 17
5.2.1 Summary . 17
5.2.2 Direct method . 17
5.2.3 Indirect method . 17
5.3 Reporting of calibration and test data. 21
5.4 Quality assurance . 21
5.4.1 Data . 21
5.4.2 Nonconformance . 21
5.4.3 Calibration . 21
5.4.4 Traceability . 25
5.4.5 Training . 25
5.5 Audit of measurement equipment . 26
5.5.1 General . 26
5.5.2 Audit of the system (acceptance) . 26
5.5.3 Annual regular review (maintenance) of the system . 27
5.5.4 Special review . 27
Annex A (normative) Calibration and test results – DRD . 28
Annex B (informative) Selection criteria for equipment and accessories for
performing the infrared analysis of organic contamination . 30
Annex C (informative) Calibration of infrared equipment . 35
Annex D (informative) Interpretation of infrared spectra . 40
Annex E (informative) The use of molecular witness plates for
contamination control . 44
Annex F (informative) Collecting molecular contamination from surfaces
by wiping and rinsing . 49
Annex G (informative) Contact test . 54
Annex H (informative) Immersion test . 56

Figures
Figure 5-1: Sampling and analysis procedure flow chart . 20
Figure C-1 : Example for a calibration curve . 38
Figure C-2 : Measurement of peak heights . 39
Figure D-1 : Characteristic spectrum of bis (2-ethylhexyl) phthalate . 41
Figure D-2 : Characteristic spectrum of a long chain aliphatic hydrocarbon . 41
Figure D-3 : Characteristic spectrum of poly (dimethylsiloxane) . 41
Figure D-4 : Characteristic spectrum of poly (methylphenylsiloxane) . 41
Figure E-1 : Witness plate holder and witness plate used for organic contamination
control . 44
Figure E-2 : Example of a witness plate information sheet . 48
Figure F-1 : Example of a sample information form . 53

Tables
Table 5-1: Standard materials used for the IR analysis. 22
Table B-1 : Important properties of common window materials used for infrared
spectroscopy . 33
Table B-2 : Examples of compound references and suppliers . 34
Table C-1 : Volumes to be applied from stock solutions and respective target amounts . 38
Table C-2 : Example results of the direct calibration method . 39
Table D-1 : Assignment of infrared absorption bands for the four main groups of
contaminants . 42

Foreword
This document (EN 16602-70-05:2014) has been prepared by Technical
Committee CEN/CLC/TC 5 “Space”, the secretariat of which is held by DIN.
This standard (EN 16602-70-05:2014) originates from ECSS-Q-ST-70-05C.
This European Standard shall be given the status of a national standard, either
by publication of an identical text or by endorsement, at the latest by April 2015,
and conflicting national standards shall be withdrawn at the latest by April
2015.
Attention is drawn to the possibility that some of the elements of this document
may be the subject of patent rights. CEN [and/or CENELEC] shall not be held
responsible for identifying any or all such patent rights.
This document has been prepared under a mandate given to CEN by the
European Commission and the European Free Trade Association.
This document has been developed to cover specifically space systems and has
therefore precedence over any EN covering the same scope but with a wider
domain of applicability (e.g. : aerospace).
According to the CEN-CENELEC Internal Regulations, the national standards
organizations of the following countries are bound to implement this European
Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
Introduction
One or more of the following organic substances can contaminate spacecraft
materials and hardware, as well as vacuum chambers:
• Volatile condensable products of materials out-gassing under vacuum.
• Volatile condensable products of off-gassing materials.
• Back-streaming products from pumping systems.
• Handling residues (e.g. human grease).
• Residues of cleaning agents.
• Non-filtered external pollution.
• Creep of certain substances (e.g. silicones).
There are several methods for identifying organic species, such as mass
spectrometry, gas chromatography and infrared spectroscopy, or a combination
of these methods. Infrared spectroscopy, which is the most widely used, is a
simple, versatile and rapid technique providing high resolution qualitative and
quantitative analyses. The technique is therefore baseline for the present
Standard.
Scope
This Standard defines test requirements for detecting organic contamination on
surfaces using direct and indirect methods with the aid of infrared
spectroscopy.
The Standard applies to controlling and detecting organic contamination on all
manned and unmanned spacecraft, launchers, payloads, experiments,
terrestrial vacuum test facilities, and cleanrooms.
The following test methods are covered:
• Direct sampling of contaminants
• Indirect sampling of contaminants by washing and wiping

Several informative annexes are included to give guidelines to the following
subjects:
• Qualitative and quantitative interpretation of spectral data
• Calibration of infrared equipment
• Training of operators
• Use of molecular witness plates
• Collecting molecular contamination
• Contact test to measure the contamination transfer of materials
• Immersion test to measure the extractable contamination potential of
materials
• Selection criteria for test equipment
This standard may be tailored for the specific characteristics and constraints of
space project in conformance with ECSS-S-ST-00.
Normative references
The following normative documents contain provisions which, through
reference in this text, constitute provisions of this ECSS Standard. For dated
references, subsequent amendments to, or revision of any of these publications
do not apply. However, parties to agreements based on this ECSS Standard are
encouraged to investigate the possibility of applying the more recent editions of
the normative documents indicated below. For undated references, the latest
edition of the publication referred to applies.

EN reference Reference in text Title
EN 16601-00-01 ECSS-S-ST-00-01 ECSS system – Glossary of terms
EN 16602-10 ECSS-Q-ST-10 Space product assurance – Product assurance
management
EN 16602-10-09 ECSS-Q-ST-10-09 Space product assurance – Nonconformance control
system
EN 16602-20 ECSS-Q-ST-20 Space product assurance – Quality assurance
EN 16602-70-01 ECSS-Q-ST-70-01 Space product assurance – Cleanliness and
contamination control
Terms, definitions and abbreviated terms
3.1 Terms defined in other standards
For the purpose of this Standard, the terms and definitions from ECSS-S-ST-00-01
and ECSS-Q-ST-70-01 apply, in particular for:
controlled area
3.2 Terms specific to the present standard
3.2.1 absorbance, A
logarithm to the base 10 of the reciprocal of the transmittance
[ASTM-E-131]
NOTE The term absorbance is also widely used for the
negative log of the ratio of the final to the
incident intensities of processes other than
transmission, such as attenuated total reflection
and diffuse reflection.
3.2.2 absorption
transfer of infrared energy to the molecules present within the pathway of the
radiation
3.2.3 absorptivity
absorbance divided by the product of the concentration of the substance and
the sample path length
NOTE 1 Absorptivity = A/(l C), where A is the
absorbance, C is the concentration of the
substance and l is the sample path length. The
-3
unit normally used are cm for l, and kg m for C.
NOTE 2 The equivalent IUPAC term is “specific
absorption coefficient”.
[adapted from ASTM-E-131]
3.2.4 attenuated total reflection
reflection that occurs when an absorbing coupling mechanism acts in the
process of total internal reflection to make the reflectance less than unity
[ASTM-E-131]
3.2.5 diffuse reflection
reflection in which the flux is scattered in many directions by diffusion at or
below the surfaces
[ASTM-E-131]
3.2.6 Fourier transformation
mathematical process used to convert an amplitude-time spectrum to an
amplitude-frequency spectrum or vice versa
[ASTM-E-131]
3.2.7 infrared spectroscopy
spectroscopy in the infrared region of the electromagnetic spectrum, i.e. with
wavelength range from approximately 0,78 µm to 1 000 µm (wave number
-1 -1
range 12 820 cm to 10 cm )
[adapted from ASTM-E-131]
3.2.8 molar absorptivity, ε
product of the absorptivity and the molecular weight of the substance
NOTE The equivalent IUPAC term is “molar
absorption coefficient”.
[adapted from ASTM-E-131]
3.2.9 radiant power, P
amount of energy transmitted in the form of electromagnetic radiation per unit
time
NOTE 1 Unit for radiant power is Watts.
NOTE 2 Radiant power should not be confused with
intensity (I), which is the radiant energy
emitted within a time period per unit solid
angle (measured in Watts per steradian).
3.2.10 reflectance, R
ratio of the radiant power reflected by the sample to the radiant power incident
on the sample
[ASTM-E-131]
3.2.11 specific area
diameter of the infrared beam at the window location
NOTE It is expressed as the ratio of the beam diameter
over the area. For example, 7 mm/0,38 cm , 10
2 2
mm/0,79 cm or 12 mm/1,13 cm .
3.2.12 transmittance, T
ratio of the radiant power transmitted by the sample to the radiant power
incident on the sample
[ASTM-E-131]
3.2.13 wave number,
ν
number of waves per unit length
-1
NOTE 1 The unit for wave number is cm . In terms of
this unit, the wave number is the reciprocal of
the wavelength, λ ( where λ is expressed in cm).
NOTE 2 The wave number is normally used as the X-
axis unit of an IR spectrum.
[adapted from ASTM-E-131]
3.3 Abbreviated terms
For the purpose of this Standard, the abbreviated terms from ECSS-S-ST-00-01
and the following apply:
Abbreviation Meaning
American Society for Testing and Materials
ASTM
attenuated total reflection
ATR
absorbance unit
AU
dioctylphthalate, synonym bis (2-ethylhexyl) phthalate
DOP
diffuse reflection infrared Fourier transform
DRIFT
deuterated triglycine sulphate IR detector
DTGS
electrostatic discharge
ESD
Fourier transform infrared (spectrometry)
FTIR
Institute of Environmental Sciences
IES
isopropyl alcohol
IPA
Infrared
IR
International Union of Pure and Applied Chemistry
IUPAC
International Organization for Standardization
ISO
mercury cadmium telluride IR detector
MCT
non-volatile residue
NVR
Polytetrafluoroethylene
PTFE
quartz crystal microbalance
QCM
refractive index
RI
signal to noise ratio
S/N
Ultraviolet
UV
volatile condensable material
VCM
Principles
Infrared qualitative analysis is carried out by functional group identification, or
by comparison of the IR absorption spectra of unknown materials with those of
known reference materials, or both. It is therefore possible to determine
structural information about the molecules of contaminants. In some cases, the
source of the contamination can be detected.
Infrared quantitative analysis of levels of contaminants is based on the
Lambert-Beer’s (henceforth referred to as Beer’s) law and requires calibration.
Infrared spectroscopy monitoring is used to verify that the stringent
contamination and cleanliness controls applied to spacecraft materials and
associated equipment are met. The most common methods for measuring
contamination are:
• Direct methods
IR-transparent windows used as witness plates (e.g. CaF2, ZnSe, Ge) are
placed in situ, for example, inside a vacuum facility, clean-room or
spacecraft. Contamination of the windows is then analysed (without
further treatment) using an IR spectrophotometer.
• Indirect methods
The contaminants on the surface to be tested are collected by means of a
concentration technique, for example by washing or wiping a larger
surface. Such a surface can also be a witness plate, which is removed after
exposure and treated in the same way. The resultant contaminated liquid
or tissue is then processed, and finally an IR-transparent or a reflective
window containing the contaminants is analysed with the aid of an IR
spectrophotometer.
The direct method has demonstrated higher reliability because the sample does
not require transfer from the witness plate and therefore reducing the error for
quantification. The indirect method allows sample concentration and can
therefore provide higher sensitivity.
Requirements
5.1 Preparatory activities
5.1.1 Hazard, health and safety precautions
a. Unavoidable hazards to personnel equipment and materials shall be
controlled by risk management procedures and kept to a minimum.
b. Hazardous substances, items and operations shall be isolated from other
activities.
c. Items and controls shall be located in order to prevent personnel to be
exposed to hazards.
NOTE Typical hazards are electric shock, cutting
edges, sharp points, and toxic atmospheres.
d. Warning and caution notes shall be included in instructions for
operation, storage, transport, testing, assembly, maintenance and repair.
e. Hazardous items, equipment or facilities shall be clearly marked to
instruct personnel that they should take the necessary precautions.
f. Before starting any operation, safety hazards shall be identified, and the
necessary precautions taken to minimize risks.
NOTE For example, use of protection devices when
chloroform is used.
g. Operations requiring safety suits and protection devices shall be initiated
after the personnel involved have the required protection, including any
specific protection devices available at the work-place.
5.1.2 Facilities
5.1.2.1 Cleanliness
a. The work area shall be clean and free of dust.
b. Air used for ventilation shall be filtered to prevent contamination of the
work pieces.
5.1.2.2 Environmental conditions
a. The ambient conditions for the test, process and work areas shall be
1. Room temperature (22 ± 3) °C and,
2. Relative humidity (55 ± 10) %.
NOTE Additional conditions can be imposed for
critical operations.
5.1.3 Materials
a. Materials used in the process shall be stored in a controlled area in
conformance with clause 5.1.2.
b. Limited-life materials shall be labelled with their shelf lives and dates of
manufacture.
5.1.4 Handling
a. It shall be demonstrated that no additional contamination is introduced
during the handling process.
NOTE 1 Contamination can be avoided by using
tweezers and clean gloves, and ensuring that
gloves and chemicals are compatible.
NOTE 2 Typically used gloves are of powder-free nylon,
nitrile, latex, lint-free cotton.
5.1.5 Equipment
5.1.5.1 Infrared spectrophotometer
a. The spectrometer shall have the following specification:
-1 -1
1. Spectral range: At least, 4 000 cm – 600 cm (2,5 µm - 16,7 µm).
-1
2. Resolution: 4 cm .
3. Absorbance of 0,0001 as detection limit for transmission methods.
b. Interferences of environmental components shall be eliminated
NOTE Major environmental interferences are caused
by H2O and CO2. Elimination of H2O and CO2 is
possible by flushing with the proper gases or
applying a vacuum.
c. Plates of infrared-transparent material shall be available.
NOTE 1 Typical materials are NaCl, MgF2, CaF2, ZnSe,
or Ge.
NOTE 2 An ATR-attachment to the spectrophotometer
can be used for direct analysis of the surfaces of
materials.
NOTE 3 The results of the ATR infrared
spectrophotometer technique are dispersed and
should therefore only be used for qualitative
purposes.
5.1.5.2 Alignment of the sample holder
a. The sample holder in the sample compartment of the infrared
spectrometer shall be aligned for obtaining quantitative information.
b. The sample holder shall be aligned so that the infrared beam is
positioned in the centre of the IR transparent window.
c. For alignment the following steps shall be performed:
1. A mask plate is made with an aperture of (1 – 2) mm diameter.
2. This mask is placed in the window holder and pointed in the
sample compartment of the spectrometer.
3. The aperture of the instrument is set to 1 mm.
4. By adjusting the position of the sample holder across the IR beam,
the optimum position is determined.
5. The sample holder is fixed at this position along the line of the IR-
beam.
NOTE It is important to keep the sample holder at this
position because in most equipment the focal
point of the IR-beam is set to be in the sample
compartment. This means that the beam
diameter can be different if this position is
changed.
6. Once the sample holder is aligned, the diameter of the beam is
measured.
NOTE The measurement of the diameter of the beam
is performed by masking the window holder,
using tape, from the top until the tape absorbs
IR light
7. Step 5.1.5.2c.6 is repeated from bottom, left and right.
8. A square is formed on the holder, which marks the area where the
IR beam passes through without touching the tape.
9. The size of the square is measured and used in further calculations.
5.1.6 Miscellaneous items
a. The following items shall be used for acquiring and preparing the
samples:
1. Pre-cleaned standard filter paper of 70 mm diameter.
NOTE For orientation on the cleaning process see
F.2.3.
2. Piece of pre-cleaned foam rubber, approximately (50 × 30) mm.
NOTE See F.2.3.
3. A PTFE film can be used to protect the foam rubber.
4. Clean, powder-free and lint-free gloves.
5. Spectral grade solvents.
6. Petri dishes ranging in diameter from (50 - 70) mm.
7. Glass rod or micro-syringe.
8. Glass syringe.
9. Tweezers.
10. Infrared lamp.
5.2 Procedure for sampling and analysis
5.2.1 Summary
A summary of the procedures contained in this clause is given in Figure 5-1.
5.2.2 Direct method
a. The following steps shall be performed for the determination of organic
contamination by the direct method:
1. Position the infrared-transparent windows at or near critical
locations.
NOTE For example, inside the compartment, the
chamber or the clean-room to be monitored.
2. Verify that the witness plate is subjected to the same conditions
that the location to be monitored.
NOTE For a representative measurement these
conditions are crucial, e.g. identical
temperature and pressure.
3. Before installation, record the spectrum of the cleaned, non-
exposed window and retain for use as a background measurement.
4. Immediately after exposure, analyse the infrared-transparent
windows with the IR spectrophotometer.
NOTE A waiting period after exposure can cause false
results due to creeping of some kinds of
contaminants (e.g. silicones).
5.2.3 Indirect method
5.2.3.1 Preparatory activities
a. Surfaces shall be washed and wiped with solvents and tissues that are
compatible with and do not damage the surface to be analysed.
NOTE 1 For example, solvation and swelling of any
material that is not regarded as a contaminant.
NOTE 2 Scratching of the surface.
NOTE 3 IPA and chloroform (CHCl3) are the most
widely used solvents.
5.2.3.2 Washing process
a. For the washing process the following steps shall be applied:
1. Place the contaminated solvent in a Petri dish, and evaporate it in a
slightly tilted position with an infrared lamp until only a few
droplets remain.
2. Transfer the droplets to the IR-transparent window.
NOTE To avoid contamination and facilitate the work,
a glass rod or a micro syringe is normally used
for the transfer.
3. Position the droplets on the window in an area corresponding to
the beam shape of the IR spectrophotometer.
4. Distribute the contaminant over the area of the IR transparent disk
covered by the IR beam.
NOTE This step is also appropriate for contaminants
or substances of low surface tension, which
tend to concentrate in small spots (e.g.
silicones). Concentration into small spots can
lead to a local saturation of the IR signal and
thus to a subsequent underestimation of the
overall concentration.
b. The window shall then be placed under the IR lamp until the solvent
evaporates leaving a thin film of contaminant on the window.
c. For quantitative transfer, the transfer process shall be repeated three
times.
d. Finally, the window shall be fitted to the IR spectrophotometer and
aligned such that the beam of the IR spectrophotometer covers the
contaminated area of the window
NOTE 1 For details of the alignment process see Annex
C.
NOTE 2 For details of the washing process, see Annex F.
5.2.3.3 Wiping process
a. The tissue shall be pre-cleaned.
b. A blank analysis shall be performed in conformance with 5.2.3.3f and
-7
5.2.3.3g until a background level of less than 5 × 10 g for any tissue size
is obtained.
NOTE Cleaning can be performed by Soxhlet
extraction or immersion in chloroform.
c. The cleaned tissue shall be stored/kept in a clean container.
d. The surface to be analysed shall be wiped eight times, twice in each of
four directions, with either a wet or dry wipe, turning the tissue each
time a little after each wiping direction.
e. Depending on the chosen type of wiping process (wet or dry), the
following steps shall be performed:
1. For a wet wipe process
(a) Fold with tweezers the pre-cleaned tissue in order to use it
as a little "sponge";
(b) Wet with spectral grade IPA or chloroform;
(c) Hold the folded tissue with curved point tweezers;
(d) Store the tissue after wiping, when the solvent is evaporated
in the transport container.
2. For a dry wipe process, cover the foam or rubber tube with a
standard filter paper and a pre-cleaned tissue.
f. The tissue to be analysed shall be immersed for 10 minutes to 15 minutes
in a known quantity of spectral grade solvent contained in a Petri dish of
70 mm diameter.
g. During the immersion time, the Petri dish shall be covered by a larger
Petri dish in order to avoid evaporation of the solvent.
h. Handling it with tweezers, the tissue shall be rinsed with 0,5 cm of
solvent on each side.
i. The Petri dish containing the contaminated solvent shall be processed in
conformance with 5.2.3.2.
NOTE For details of the wiping process see Annex F.
Direct method
2. Complete exposure.
1. Position sensors i.e.
3. Analyse spectra.
Remove sensors and fit.
IR-transparent windows.
(See Annex D )
(See 5.2.2) (See 5.2.2)
Indirect method
1. Wash surface with solvent and collect
1. Pre-clean tissues in fresh solvent until
in Petri dish.
-7
background level < 5 × 10 g.
(See 5.2.3.1)
(See 5.2.3.3a and 5.2.3.3b)
2. Evaporate solvent under IR lamp until
2. Store in glass jar.
few droplets remain.
(See 5.2.3.3c)
(See 5.2.3.2a.1)
3. Wipe contaminated surface eight
Wash Petri dish.
times, with wet or dry wipe.
(three times)
(See 5.2.3.3d)
(See 5.2.3.2c)
3. Transfer to IR-transparent window
4. Immerse tissue in Petri dish containing
using glass rod or micro-syringe.
solvent.
(See 5.2.3.2a.2)
(See 5.2.3.3f)
5. Remove tissue and process Petri dish
4. Control area of droplets.
containing contaminated solvent as per
Evaporate remaining solvent leaving
washing process.
film of contaminants on window.
(See 5.2.3.2)
(See 5.2.3.2a.3)
5. Transfer to spectrophotometer.
Align the window, so that the infrared
beam covers the contaminated area.
(See 5.2.3.2d)
6. Analyse spectra obtained.
(See Annex D)
Figure 5-1: Sampling and analysis procedure flow chart
5.3 Reporting of calibration and test data
a. Calibration and test data shall be documented in conformance with Annex
A – DRD.
b. The surface area for the direct methods shall be based on the diameter of
the IR beam diameter at the position of the sample window.
c. For indirect methods the surface area shall correspond to the surface area
washed or wiped.
d. For contact or immersion tests, the surface area shall correspond to the
contact surface of the sample.
5.4 Quality assurance
5.4.1 Data
a. Quality assurance records and log sheets shall be retained for ten years
after they have been established.
b. Log sheets shall include the following information:
1. Trade names and batch numbers of the materials under test.
2. Name of the manufacturer or supplier through whom the purchase
was made.
3. Summary of the preparation and conditioning schedule including
the cleaning procedure.
4. Any noticeable incident observed during the measurement.
5. The obtained results.
5.4.2 Nonconformance
a. Any nonconformance that is observed during the measurement
procedure shall be dispositioned in conformance to ECSS-Q-ST-10-09.
5.4.3 Calibration
5.4.3.1 General
a. Equipment shall be calibrated for obtaining quantitative information.
NOTE Calibration methods are described in Annex C.3.
b. Equipment shall be calibrated after alignment.
c. The supplier shall calibrate any measuring equipment to traceable
reference standards.
d. The supplier shall record any suspected or actual equipment failure as a
project nonconformance report in conformance to ECSS-Q-ST-10-09.
NOTE This is to ensure that previous results can be
examined to ascertain whether or not re-
inspection and retesting is necessary.
e. The standard materials used for the IR analysis as described in Table 5-1
shall be used.
Table 5-1: Standard materials used for the IR analysis
a -1
Standard Chemical nature Characteristic peaks (cm )
b
Paraffin oil Long chain aliphatic hydrocarbon 2 920
Bis(2-ethylhexyl) phthalate (DOP) Aromatic ester 1 735
Poly(dimethylsiloxane) Methyl silicone 1 260, 805
Poly(methylphenylsiloxane) Methyl phenyl silicone 1 260, 1 120, 805
a
Standard materials should be of highest grade available, examples are given in Annex B.3.
b -1 -1
The ratio of peak heights (peak to baseline) between CH2 (2 925 cm ) and CH3 (2 955 cm ) should be between
0,60 – 0,65.
f. If different types of contaminants are frequently found, individual
calibration curves for each type of contaminant shall be made upon
customer’s request.
g. The calibration curve that is produced using the direct method shall take
into account the transfer efficiency factor when being used for the
indirect method.
h. The transfer efficiency factor shall be determined by measuring the loss
of signal due to the transfer step from the Petri dish to the window.
NOTE For experienced operators, this factor is almost
1, but for less experienced operators it can be
significantly less. Operators are for this reason
evaluated annually.
i. The standards materials used for the calibration lines shall be of high
purity.
j. Chloroform used shall be of spectroscopic grade, having a non-volatile
residue (NVR) < 5 µg/g.
k. The absorbance level of the NVR shall be lower than 0,000 1 AU in order
to minimize disturbances.
l. NVR absorbance shall be determined by evaporating 10 ml of chloroform
and recorded by means of IR spectroscopy.
m. The standards materials shall be conserved in a cool and dark area and
the evaporation of chloroform limited by sealing the measuring flask.
5.4.3.2 Calibration method
a. The calibration shall be performed covering the required concentration
range.
-8 2   -6 2
NOTE Typical range is 5 × 10 g/cm to 5 × 10 g/cm .
b. Measurements shall be performed by transferring a defined volume from
the standard stock solution directly onto the IR-window.
c. The following steps shall be followed:
1. The gas-tight syringe is filled with a defined volume from the
standard stock solution.
NOTE 1 Example of stock solution range as given in
Table C-1.
NOTE 2 A typical process for the preparation of
standard solutions is described in C.3.2.
2. The droplets from the syringe are positioned in the centre of the
IR-window, within the area where the IR beam covers the window.
The window is placed above a circular mask that corresponds to
the size of the IR beam, and viewed from above the window using
a magnification device.
3. The IR-window is positioned in the sample compartment of the
spectrometer.
4. The spectrum is recorded and the transmission loss for the
respective standards is measured at the following wave numbers
(see also Table 5-1):
-1
(a) 2 920 cm for hydrocarbons,
-1
(b) 1 735 cm for esters,
-1 -1
(c) 1 260 cm or 805 cm for methyl silicone,
-1 -1 -1
(d) 1 260 cm , 1 120 cm or 790 cm for methyl phenyl silicones.
d. Each point shall be measured at least three times, possibly with different
windows in order to eliminate systematic errors.
5.4.3.3 Calibration curve
a. The peak quantification shall be performed by measuring peak height or
peak area.
NOTE An example of such measurement is given in
C.3.3.
b. The calibration curve shall have a correlation coefficient higher than 0,98
for six sample points.
NOTE A typical calibration curve is shown in C.3.3.
c. The same method of quantification shall be used for the measurement of
the contaminant to be analysed.
d. The detection limit of the analysis shall be calculated by using the S/N
ratio at the specific wave number used for quantification.
e. The detection limit of the analysis shall be specified and reported in
Mass/specific area.
f. For the direct method, the detection limit shall be three times the S/N
ratio.
g. For the detection limit of the indirect method , the following shall be
verified:
1. The surface area of the witness plate or wiped area.
2. The NVR of the solvents used.
3. The extractable materials from the tissues used for wiping is less
-7
than 5 × 10 g.
4. The precision of the background correction for the NVR of the
solvent and the tissue.
5.4.3.4 Calibration results
a. Contamination levels shall be expressed in terms of the contribution of
the following four main group equivalents: hydrocarbons, esters, methyl
silicones, and phenyl silicones.
b. The calculation shall be performed using their characteristic group
frequencies in conformance with Table 5-1, and the peak maximum of the
same vibration mode as for deriving the calibration curve.
NOTE 1 Unless the contaminant matches the calibration
standard, quantification is always relative to
the reference material and thus semi-
quantitative.
NOTE 2 A different chemical environment from a
functional group (e.g. substitution, or
neighbouring group effects) can lead to shifts in
the frequency of the respective vibration
modes.
5.4.3.5 Limit of detection
a. The noise level of the equipment shall be measured at the wave numbers
-1 -1 -1
of the calibration standards (2 920 cm , 1 730 cm and 800 cm ).
b. The noise level shall be at least three times less than the signal in order to
recognize a signal.
c. For indirect methods, the contribution of the following criteria shall be
considered:
1. the purity of the solvents,
2. the cleanliness of wipes,
3. the transfer efficiency of residue.
d. For indirect methods, all solvents used shall have a NVR of less than 5
-1
µg/g and an infrared absorption of the NVR of less than 0,000 5 AU ml .
NOTE If the rinsing method is used (see Annex D and
Annex E), a detection limit in the order of
-8 -2
10 g cm can be obtained depending on the
surface area analyzed (e.g. for a 15 cm witness
plate).
e. For the wiping method, the used tissue shall have a contamination
-7
potential of less than 5 × 10 g.
NOTE 1 For description of the wiping method see Annex
F.
NOTE 2 With a wiped area of 100 cm , the detection
-8 -2
limit of about 2 × 10 g cm can be reached.
5.4.4 Traceability
a. For traceability ECSS-Q-ST-20 shall apply.
5.4.5 Training
5.4.5.1 General
a. For training ECSS-Q-ST-20 shall apply.
5.4.5.2 Specific training
a. Trained and competent personnel shall be employed for all calibration
and analysis operations.
b. A training programme shall be developed, maintained and implemented.
NOTE The training programme is set up to provide for
excellence of workmanship and personnel skills
as well as for thorough knowledge of the
requirements detailed in this Standard.
c. Trained personnel performing calibration and analysis shall be certified.
d. The certification of personnel shall be based upon objective evidence of
reproducibility and accuracy.
e. Personnel shall be retrained or re-assessed annually to maintain the
required skills.
f. Certification status of personnel shall be recorded and maintained.
5.4.5.3 Training procedures
a. Operators shall be trained by preparing a hydrocarbon standard solution
by the following procedure:
1. A gas-tight syringe is filled with the standard solution containing
-6
an equivalent of 1 × 10 g analyte and put in the Petri dish.
2. The sample is transferred drop-wise with the glass rod or micro-
syringe from the Petri dish onto the IR-window within the area of
the IR-beam.
3. After all droplets are transferred to the window, the Petri dish is
washed with a few droplets of fresh chloroform and transferred
again according to step 2.
4. Step 3 is repeated at least twice.
5. The IR-transparent window is placed on the sample holder in the
sample compartment of the pre-aligned spectrometer.
6. The spectrum is recorded and the transmission loss for
-1
hydrocarbons at about 2 920 cm is measured.
7. Steps 1 to 6 are repeated 10 times.
b. All 10 measurements shall be within 20 % of the average value.
NOTE Experienced operators are able to perform this
test within 10 % of the average value.
c. Once the positioning or transfer of the solution can be performed within
the accepted limits, the trainee operator shall start to produce the
calibration curves.
NOTE For the calibration curves see Annex C.3.
5.5 Audit of measurement equipment
5.5.1 General
a. The customer shall perform the standard audit in conformance to ECSS-
Q-ST-10 clause 5.2.3 “Project PA audits”.
NOTE 1 The main purpose of this audit is to ensure the
validity of test results by comparison of the test
data on identical materials by different test
houses.
NOTE 2 The infrared spectra from test houses for the
projects of the customer, obtained in the
manner laid down in this Standard, are only
accepted for the projects of the customer if the
test house is certified to perform the relevant
procedure in this Standard.
5.5.2 Audit of the system (acceptance)
a. The customer’s product assurance department shall audit the
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