Using ENVF
Facilities
How can I access the equipment in ENVF?
You should be a
registered user in ENVF.
In addition,
for using the Major Analytical or Biological equipment, you should take the
familiarization course of that equipment provided by ENVF, or declare
competency in using that particular equipment.
What are the requirements to become ENVF
registered user and how to register?
To become a
registered user, you MUST fulfil the following requirements:
(i) You must be
a frequent laboratory user in his/her own department.
(ii) You must
have completed all the necessary HSEO Mandatory Safety Training Courses.
For analytical
equipment: MC07 Chemical Safety I, MC03 Chemical Safety II
For biological
equipment: MC06 Biological Safety, MC05 Pressure Safety (for user who use
Autoclave)
Download the
registration form from this link
http://envf.ust.hk/documents/User_Registration_and_safety_clearance_form.pdf
Send an email
to envflab@ust.hk to arrange a time slot for safety clearance with the safety
officer of ENVF.
After the
safety clearance, your registration is completed. Please also take your time to
read the policies and rules of ENVF
http://envf.ust.hk/documents/ENVF_Rules.pdf
How to become a Qualified User of a specific
major equipment?
There are two
ways to become a Qualified User.
1. You must have completed the familiarization course of the specific
major equipment provided by ENVF. The schedule of familiarization courses is
shown in ENVF's WEB page.
http://envf.ust.hk/training.html
User also can
take an individual video training at ENVF Laboratory (RM 4109) during normal
office hours. User need to make an advance booking as places are limited each
day.
Click this link
to access the booking schedule
http://envflab.ust.hk/booking/trainingroom-auth.php
2. Or you and your supervisor have completed and signed the User
Competent Registration Form
http://envf.ust.hk/documents/Competent_Registration_V1_2.pdf
Then send the
form to envflab@ust.hk or submit it to room 4112 to update your competency. We
assume you are capable of operating the equipment both hardware and software
after you have signed the competent form.
How frequent are your trainings provided?
Mass section of
trainings will be provided in 1st and 2nd semester each
year. On demand video training will also be provided. Please refer to ENVF web
page for details.
Can I enter ENVF facilities by using my
HKUST Access Card?
After you have
completed the registration, we will grant your access right to room 4109 and/or
Service corridor (Biological Facility) during office hour (09:00 – 17:00)
within 3 working days.
If user cannot
access the facility after the mentioned period, please email to envflab@ust.hk
or come to room 4112 during office hour to fix the issue.
How to book or view the availability of the
equipment?
The
availability of the equipment can be viewed and it can be booked from this link
http://envflab.ust.hk/booking/
or through the
web page
http://envf.ust.hk/equipment_list.html
Can I work inside ENVF after office hour?
For long
experiments that need extended working hours in ENVF Laboratory, please
complete the Extended Hour Form and send it to envflab@ust.hk or submit the
form to room 4112.
http://envf.ust.hk/documents/Extended_Hour_V7.pdf
You MUST
observe all the “Additional rules" for working outside office hours
specified in the Policies and Rules.
How can I request ENVF Services?
You can submit
a service request through the hyper link “General Request Form” on the ENVF web
page
http://envf.ust.hk/equipment_list.html
We only accept
services that are environmental related experiments and projects. Kindly note
that we reserve the right to decline any service that we are not capable of.
Please discuss with us using envflab@ust.hk or drop by room 4112 before issuing
the service request.
How can I contact ENVF?
You can contact
ENVF via the following emails
For data base
usage or web page issue, please contact webenvf@ust.hk.
For equipment,
training and laboratory related, please contact envflab@ust.hk
or drop by room 4112.
For training
issue, please contact envftraining@ust.hk.
Equipment Related
FAQs
Energy Dispersive
X-Ray Fluorescence (EDXRF)
There is no familiarization course for
EDXRF. How can I analyze the sample using this equipment?
Due to license
issue, EDXRF can only be operated by ENVF staff members who are registered in
Hong Kong Radiation Board. User can submit the sample to us directly and raise
the request using the same procedures of using major equipment via the web page
http://envf.ust.hk/equipment_list.html
Please contact
and discuss with our staff for the measurement requirements before submitting
the sample or raising the request.
Do I need to prepare the sample for EDXRF
measurement?
ENVF only
provide the measurement service and we will not provide sample preparation.
Please discuss your sample type and how to prepare your sample with our staff
first.
Can I quantify the elements in my sample?
Yes, if user
can provide standards with the same physical form and similar matrix, the
measurement accuracy will be good. For example, measurement of elements inside
a steel against a calibration of a series of known elements concentration steel
standards.
If user cannot
provide standards with the same form and matrix, the results obtained are
semi-quantitative (estimated using standardless method). There is no guaranty
of the accuracy, due to the matrix effect and other physical effect such as
particle size effect, as uncertainty cannot be estimated.
Is EDXRF measurement non-destructive to the
sample?
It is
non-destructive to most of the sample that is not vacuum sensitive. If the
sample can be affected by vacuum, we can use He medium for the measurement in
the expense of sensitivity of some light elements. Please discuss your sample
types and requirements with our staff before submitting them to us.
Inductively
Coupled Plasma - Optical Emission Spectrophotometer [Perkin Elmer/Avio 200]
How much sample do I need to place in the
autosampler?
The autosampler
accepts 15 mL conical tube. The minimum volume of sample depends on the users
method requirements. 10 mL will be adequate for a method with typical
measurement time of less than 240 sec per sample.
If user has only
2 mL or less sample and dilution of sample to the required volume is not an
option, user should seek for another technique. In this case GFAA (Graphite
Furnace Atomic Absorption with Zeeman background correction) will be more
suitable for metallic elements measurement at such a small sample volume.
However, ENVF does not have GFAA system. Please look for other department in
HKUST for this instrument.
What is the detection limit of AVIO 200?
Instrument
detection limit of AVIO 200 is in low µg/L range for most of the elements when
it is operated in axial view whereas it is in high µg/L range when it is
operated in radial view.
User should
note that this is the instrument detection limit (3 standard deviation of
signal noise) of typical suggested emission lines and it is not the method
detection limit which depends on sample matrix, analysis method and the
required confidence limit such as LOQ (Limit Of Quantitation) or PQL (Practical
Quantitation Limit).
What concentration range of standards
should I prepare?
The concentration
range of standards depends upon elements and the selection of emission lines.
The following ranges give user a rough idea only:
Radial
view: From 1, to 1000 µg/mL
Axial
view: From, 0.1 to 100 µg/mL
In case of
detector saturation occur at the concentration range required, user might
select attenuation mode in Syngistix software.
Can I measure the elements in oil sample
without digestion?
Our system can
be changed with organic torch that can handle non-volatile organic solvent such
as kerosene and xylene. User can dilute the oil sample with kerosene and then
measure with the organic torch. Of course users should prepare the element
standards in oil/kerosene matrix and inform ENVF staff to change the torch
before booking it. ENVF might revert the torch back to aqueous type by default
after user's usage.
Can I measure hydride forming elements in
order to achieve a lower detection limit (about 5-10 times lower than axial
view)?
Yes, our
AVIO200 is equipped with vapour generation unit. Please inform ENVF staff to
configure the vapour generation unit prior to your analysis.
If my sample is digested with HF, can I use
it with the AVIO 200 ICP?
Yes, please use
all plastic sample introduction system Ryton Scott Spray chamber. The glass
cyclone spray chamber cannot be used. Please ask ENVF staff for help if you are
not sure.
Can I aspirate sea water sample directly
into AVIO 200 ICP?
The default
aqueous cross-flow nebulizer can handle dissolve solid up to 5% and so typical
sea water sample (~3.5 % dissolve solid) can be introduced into AVIO 200
without the need of dilution.
Unlike ICP-MS
that can typically handle 0.2% dissolve solid continuously or 0.6% for short
period without the possibility of affecting the MS interface and cause a performance
drift, AVIO 200 can handle high dissolve solid and it is limited by the type of
sample introduction system installed in it only.
The detection of the my analytes that have
emission lines below 200 nm are poor. How to resolve this?
Check that you
have purged with high flow of nitrogen into the optical system when measurement
lines are below 200 nm. Below 200 nm Oxygen, Water and Carbon Dioxide in the
air starts to absorb radiation significantly and reduce the emission signal to
reach the detector. This is the VUV (Vacuum Ultra Violet) region. Purging the
optics with dried nitrogen will significantly improve the signal attenuation
due to the air. The nitrogen feature absorption bands become significant
at wavelength below 145 nm which is far below the wavelength range of the
instrument (165 - 900 nm).
I found my results always higher/lower than
expected. What is the problem?
Please check the
spectrum for any spectral interference. Use either Multicomponent Spectral
Fitting (MSF) model or Inter-element Correction (IEC) to solve the problem in
case choosing other emission lines is not an option (such as not sensitive
enough). Please refer to the handout from ENVF or the software manual on how to
set up these models.
Another issue is
unmatched physical properties of standards and the sample. If sample contains
surfactant, have viscosity different from the standards or have significant
different in dissolve solid content, please prepare a standards with similar
sample matrix or use the standard addition method to solve the problem.
Do ENVF provide ICP standards or
consumables?
No, ENVF will
not provide ICP standards. ENVF will charge additionally some equipment related
consumables that will not be shared by users such as sample vials used in the
autosampler if user request these items.
On the other
hand, gas, Type I reagent water and sample tubing that are necessary for the
instrument operation and items that is shared by users will be provided without
additional charge.
Gas Chromatograph
(including Mass Selective Detector System both EI and CI, ECD, FID)
Can I use GC to separate and measure
alcohol or other organic compounds with carbon number equal or less than C2?
ENVF don't have
the column that can separate compounds with carbon number equal or less than C2
at near ambient temperature. For this type of application, the suitable column
is HP Plot-Q -PT column, PoraPLOT U (0.32mmID or 0.25 mmID X30m with particle
trap), DB-ALC1, DB-ALC2 etc. Users should consult literature to
select the suitable column for their applications.
Can I measure volatile organic compounds
(VOCs) in aqueous solution using the GCMS or GC-FID, GC-ECD?
Yes, you can
use our head space sampler to extract the VOCs from water and inject into the
GCs system automatically.
You can buy
SPME (Solid Phase Micro Extraction) to extract the organic compounds from
water and inject manually into the GC system if head space sampler is not
sensitive enough for the analysis or the target organic compound is not that
volatile.
Why ENVF require user to use its own
injector liner?
Since the GCs in
ENVF is a communal system and different users might have different sample types
and analysis methods, cross contamination of injection liner with another
user's sample residual is plain to see in the inlet. Hence, for the sake of
minimizing the possible issues due to cross contamination, users are encouraged
to use their own liner.
Will ENVF provide solvent for needle
washing?
No, ENVF will
not provide solvent for needle washing. User need to prepare their solvents.
What type of consumables will be provided
by ENVF?
Gas that are
necessary for the instrument operation such as carrier, reagent and makeup gas
will be provided.
ENVF also
provide communal column to user who does not have their own column. However,
ENVF will not not have any liability to ensure a contamination free and low
bleeding column. ENVF can provide DB5MS and DB35MS with typical column
dimensions (30 m, 0.25 mm ID, 0.25 µm film thickness column).
On the other
hand, ENVF will charge additionally to some equipment related consumables that
will not be shared with other users such as injector liner, ferrules, nut,
sample vials etc., if user request these items.
Why we need to derivatize the sample in
some applications when using GC as the measurement technique?
In order to
analyze compounds by GC method, the compounds should be volatile enough at the
GC operation temperature. For compounds that are not volatile enough or
unstable on heating, they should be derivatized to facilitate analysis by gas
chromatography. Sometimes derivatization might improve the detection (increase
the detection sensitivity using detector such as ECD or stabilize the ions
formed in EI mode during MS measurement) and chromatographic behaviour such as
broad peak for some compounds. The common derivatization reactions include
acylation, alkylation or silylation. Please refer to literatures for detailed
information and procedures.
How long does it take to change a GC column
in GCMS system?
ENVF's GCMS does
not have fast vent module installed and so it takes at least one working day to
change the column. Unlike other GC detector, the MS system is under
vacuum. It takes about one to two hours for cooling before the MS can be vented
and changed with a new column. It takes another two more hours to pump down and
thermal equilibrate the MS system before it can be tuned.
ENVF recommend
to wait overnight before tuning the MS system again.
For GC with ECD
and FID, the time requires to change the column is about 2 to 4 hours including
cooling and heating time of the inlet and detector.
Can I tune the MS myself?
Yes, the tuning
is automatically after user has invoked the procedures through the software
menu/button.
Why I need to check for air leak in MS
before analysis?
Sometimes an air
leak in GCMS interface will be found after certain GC temperature program
thermal cycles. This is especially the case when a new Vespel Graphite ferrule
is installed (due to shrinkage of the new ferrule). Air leak will cause premature
failure of detector, contamination of ion source/quadrupole, detection
sensitivity issue etc.
UV/VIS/NIR
Spectrometer
Is there any temperature control for the
integrating sphere?
No, there is no
temperature control for the integrating sphere. The temperature control come
with the system is only used with liquid sample compartment.
What is the specimen size when performing
reflectance measurement?
The size of
sample should be larger than 24 mm diameter when no custom made mask has been
used.
User can made a
custom sample mount and mask for sample with size smaller than 24 mm.
Do ENVF have mount for sample in the
transmittance and the reflectance port?
ENVF do not
provide any mount for sample that can be installed in these ports as different
sample shape or form requires different mounting method.
My spectrum below 200 nm are very noisy.
How to resolve this?
Check whether
there is any nitrogen purge to the sample compartment and the optical system.
Below 200 nm Oxygen, Water and Carbon Dioxide in the air starts to absorb
radiation significantly and reduce the emission signal to reach the detector.
This is the VUV (Vacuum Ultra Violet) region. Purging the optics and sample
compartment with dried nitrogen will significantly improve the signal attenuation
due to the air. The nitrogen feature absorption bands become significant
at wavelength below 145 nm which is far below the lower operation wavelength
range of the instrument (175 nm).
Scanning Electron
Microscope with EDX System
What is the maximum size of sample that can
be placed in Hitachi TM3030 SEM?
Sample with
dimensions as large as 70 mm diameter and 50 mm thick can be handled by this
microscope.
What sample requirements should be meet
before it can be examined by this SEM?
Sample must be
conductive, vacuum insensitive and non-magnetized unless user has a specific
device to shield/hold the samples and conduct the electron away to tackle the
charge up phenomenon.
What is vacuum sensitive sample?
Since SEM is
operated under vacuum, sample with water content (biological sample) or sample
with volatile components that will damage the structure due to uncontrolled
dehydration/out gassing during the evacuation process are classified as vacuum
sensitive sample.
How to prepare the sample so that it can
meet the sample requirements?
Please refer to
the ENVF's familiarization training handout for details.
Do I need to coat gold on the sample for
SEM?
Coating a gold
layer is usually required for non-conducting sample when observed in ENVF's
SEM. For slightly conductive sample, coating a gold layer will improve the
image quality even though you can view the specimen under charge reduction
mode.
However, if you
are plan to do EDX for elemental mapping, you should take into account of the
effect of gold layer. Gold layer might interfere the mapping by
overlaying a gold fluorescence signal on top of other elements and sometime
might attenuate the signal coming out of low atomic number elements beneath it.
If user has
other device, solution or apparatus that can minimize the charge up effect by
conducting the electron to the stage, then coating gold is not necessary. ENVF
do not provide these types of devices/solution at the present moment.
Can I use EDX setting to view my sample?
Yes, it is the
same as view the specimen with 15 kV potential energy. However, using EDX
observation mode will shorten the life of filament as the current pass to the
filament is higher than that of using 15 kV mode. EDX mode is just like shining
the specimen using the same wavelength light source that has higher intensity
than that of 15kV mode.
We would also like to know whether the
SEM/EDX can detect boron element.
Yes, according
to the data sheet. The EDX system can measure Boron.
https://www.hitachi-hightech.com/file/us/pdf/library/literature/Quantax70-TM3000-HTD-E186.pdf
However, due to lower fluorescence energy
(especially for low atomic mass element such as B, C ...), only boron atoms
that are close to the sample surface will be detected. Boron inside the sample
cannot be detected.
Please check for the depth of analysis of
elements
http://www.xrf.guru/Concepts/DepthOfAnalysis/index.html
TOC System
Which chemicals are used to be the standard
for water and solid sample?
For water
sample, three standards could be used. Potassium Hydrogen Phthalate is used for
Total Carbon, and Sodium Carbonate and Sodium Hydrogen Carbonate are for
Inorganic Carbon. Sodium Nitrate is used for Nitrogen content. For solid
sample, two standards could be used. Glucose (40% C) is used for Total Carbon,
and Sodium Carbonate (11.3% C) or Sodium Hydrogen Carbonate (14.3% C) is used
for Inorganic Carbon.
Should we prepare and refill the IC
reagent?
Yes! IC reagent
should be checked and refilled before starting. IC reagent is 17% Phosphoric
acid.
Should we use distilled or deionised water
for the water tank?
Milli-Q water is
used only which TOC value is lower than 0.1 ppm.
What is the suitable sample vials for water
samples?
Only one size of
sample table for this TOC model, the glass sample vial is 24 ml in volume, and
85mm Height x 23mm OD in size.
I would like to analysis Nitrogen content
in solid sample, how?
No! In this
model, there are no such devices for nitrogen analysis in solid sample.
What size of sample boat should be used for
solid sample?
In this model,
only 1 inch ceramic sample boat is used. Which should be got from Hong Kong
dealer, Comfort Technology Ltd.
Should I get the user manual?
Yes! It would
send it to you after video training and as requested.
Does water sample has been filter before
analysis?
It should be
better if any suspended particles could be seen. Sampling line will be blocked
if large particles is in.