Laboratory for Microanalytical Services

Sample preparation and submission guidelines

Dear user(s) of the Laboratory for Microanalytical Services

We do our best to provide accurate and reliable results. Good sample preparation is essential for achieving the best results.

Please follow the advice below when preparing and submitting your samples. This will help us avoid problems and delays and is in your own interest.

We reserve the right to reject samples for analysis if the vials are insufficiently labelled or if the submission form is incomplete.

Thank you for your cooperation!

Sample Identification

  • Submit each sample in a clean, tightly sealed vial with a clearly printed label.
  • Use a unique sample identifier consisting of letters and numbers (e.g., MAWO 001, JUBA 15).
  • Avoid Greek letters, superscripts, subscripts, spaces, or special characters that may not reproduce correctly in reports.
  • Never reuse sample identifiers. If submitting repeat preparations, append a sequential number or letter (e.g., MAWO 001A, MAWO 001B).
Eppendorf tube with a correctly labelled sample.

Please label each sample according to the example shown above.

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Documentation

Please provide a completed submission form electronically including:

  • contact information
  • sample ID
  • molecular/structural formula
  • sample properties
  • requested analyses (C/H/N/S, O, P, halogens, etc.)
  • expected elemental composition
  • duplicate analysis requirement

Please also clearly identify any hazards or special handling requirements, including sensitivity to air or oxygen, moisture, light, temperature, pressure, other specific storage or handling conditions.

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Sample Quantity

Determinations

Quantity per single determination [mg]

C, H, N, S (combined)

2

O, P, X (each)

4
Please provide us with as much sample material as possible. Any unused material that is not required for testing can be returned upon request.

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Sample Quality

The quality of the analytical result depends on the submitted sample.

Samples should be:

  • homogeneous
  • representative of the bulk material
  • free of residual solvents
  • free of water (unless intentionally present)
  • free of dust, filter fibres, grease, or other contaminants

Poorly mixed or contaminated samples produce inconsistent duplicate analyses.

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Recommended Sample Containers and Packaging

Our preferred sample container is a 1 mL Eppendorf vial. The tapered bottom is well suited for recovering the last particles of a sample during handling and analysis.

The lids provide a sufficiently gas-tight seal for many applications. In internal tests, P2O5 stored in such a vial for 48 hours at 50% relative humidity showed no significant increase in mass.

The lids can also be opened and closed easily with one hand, which helps minimise the sample's exposure to air during handling.

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Important: Do not use Parafilm on Eppendorf vials!

Please do not wrap Eppendorf vial lids containing samples for analysis with Parafilm®.

Parafilm does not significantly improve the airtightness of the vial and may pose additional risks during sample handling and preparation:

  • removal of the Parafilm may cause the vial lid to open unintentionally
  • the elastic film may become trapped between the vial lid and the vial body
  • small fragments of Parafilm may detach during removal
  • detached Parafilm fragments may contaminate the sample, affecting the analytical results

Parafilm is composed primarily of carbon- and hydrogen-containing materials and may therefore significantly affect the measured elemental composition of a sample if contamination occurs.

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Liquids and Oils

Liquids, viscous oils, and sticky materials are difficult to transfer quantitatively.

Please:

  • use the smallest suitable vial
  • avoid coating the vial walls
  • provide sufficient excess material
  • ensure the sample is well sealed to prevent leakage
  • use a container that remains securely closed during transportation

For liquid samples intended for express delivery by air freight, special attention must be paid to sealing. Air freight exposes packages to reduced air pressure, which can increase the risk of leakage from inadequately sealed containers.

For liquid samples, we recommend using screw-top vials with an elastic sealing element that maintain a secure seal under reduced-pressure conditions.

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Unknown or Non-Stoichiometric Materials

For polymers, technical products, environmental samples, reaction mixtures, and heterogeneous materials, a single determination is generally insufficient. 

For homogeneous samples, duplicate analyses are recommended, whereas triplicate or quadruplicate analyses are advisable for heterogeneous materials. 

Replicate measurements improve the reliability of the estimated elemental composition and provide a more representative assessment of the true sample composition.

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Returned Samples

Because all elemental analyses are destructive, only the unused sample material can be returned  upon request.

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Good Laboratory Practice

Sample Preparation and Shipment:
To ensure reliable analytical results:

  • Submit well-dried (at least 24 h under high vacuum) and homogeneous samples.
  • Submit sufficient material to allow repeat analyses if required.
  • Use clean and appropriate sample containers.
  • Do not use Parafilm to wrap Eppendorf vial lids.
  • Package samples securely to prevent contamination, degradation, or loss during transport.

Documentation and Sample Information
To facilitate correct handling and interpretation of the results:

  • Use unique and unambiguous sample identifiers that correspond to the accompanying documentation.
  • Provide complete chemical information, including the expected molecular formula where available.
  • Clearly identify any hazards or special handling requirements (e.g., air, moisture, light, or temperature sensitivity).

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Submission Form (DOCX)

Please submit the completed submission request form electronically to the following email address: service.mikrolabor@univie.ac.at