ISO 22581-2021 pdf download.Surface chemical analysis – Near real-time information from the X-ray photoelectron spectroscopy survey scan – Rules for identification of, and correction for; surface contamination by carbon-containing compounds.
If Carbon_is is Yes and Carbon_Sample is No then Carbon_Contamination_i is Yes 1).
Rule 1 merely expresses what is obvious, that if Cis is identified in the spectrum then the element carbon will contribute to the overall analysis of the material, even if this is not expected by the sample provider. There is thus a possibility that a contamination film is present on the surface.
This rule is also used to stop the automated procedure, i.e. if carbon is expected to be present in the sample then it will not be possible to establish whether there is a contamination layer without interactive examination of the spectra by the analyst.
An important indicator of the presence of a contamination film comes from prior knowledge of the expected composition and the history of the sample. This information will be supplied by the owner of the material to be analysed and is discussed in more detail in the following paragraph. However, this knowledge is encapsulated in Rule 2:
If Sample is Aqueous_Exposed or Air_Exposed or Spectrometer_Unbaked then Carbon_Contamination_2 is Yes (2). These two Rules illustrate the use of Objects, such as CarbonSample. or Carbon_ Contamination that can take values of Yes, or left at the default value of No. Carbon_Contamination is an example of an Object that can be given values from the operation of two or more rules. To record these values a ‘counter’, N, has been concatenated to the Object, i.e. Carbon_Contamination_N so as to be able to group these values, enable consensus to be reached, and set the value of the un-concatenated Object, Carbon_Contamination to Yes or defaulted to No. Objects typically take the values Yes or No, according to whether or not they are satisfied by the operation of a Rule or Rules. The Objects used in this document are defined in Table 2.
5.3.2 Rules for use of the sample history
The most likely source of carbon contamination arises from initial collection of the sample, its subsequent handling and the conditions of transport. Little can be done to ameliorate contamination arising during collection; for example, electrodes are likely to pick up contamination as they are removed through the meniscus layer of the electrolyte and many samples of technological interest will suffer from similar problems during collection. Transport of the sample in plastic bags is also endemic, and clear instructions need to be issued to clients of a user laboratory. Thus the history of the sample can help in establishing an opinion that the carbon observed in the spectrum is a contamination film; thus building on knowledge that contamination will arise from exposure to the environment. In one- to-one discussions between analyst and client, the history can he recorded but such ‘surgery’ type interviews are time consuming and expensive. Thus, a succinct means of establishing relevant history is necessary for an automatic appraisal of the survey scan. An ideal description of the sample might include the question: ‘has the sample been exposed to unfiltered air or other gaseous atmosphere or to an aqueous environment? A yes or no answer is all that is required to set a value for Carbon_ contarnination_2. This will be recorded as one piece of evidence by Rule 2, given in Tahki.. A suggested route giving a sequence by which the following rules might be applied is given in AnnxA.
5.3.3 Rules for use of peak positions
Knowledge of the sample type and its history suggests that information might be gained from regions other than that of the Cis peak. If the Ois peak is likely to be present in the acquired spectrum, then its position will show less variation with composition than that of Cis peakl9l. ISO 22581 pdf download.