< Previous10 HMRC BRIEF 15 AND ITS POTENTIAL IMPACT FOR THE METROLOGY & TESTING INDUSTRY By David Hooper MBA, Managing Director of Hooper and Co International Trade Consultancy Ltd bmta.co.uk 10 However, as the brief states under HMRC authorised special procedures, non-UK goods can be imported for repair or processing whilst import duty and VAT is suspended. However, once a business has obtained an authorisation from HMRC, it is not without significant issues. For the temporary movement of goods across borders there are three potential HMRC authorisations that could be sought: Inward Processing This authorisation allows for the temporary importation of goods by non-owners where there is a process performed that results in financial gain by the processor. This is the authorisation you should use if customers, from anywhere outside of the UK, send you goods for testing, measurements, calibration, repair etc and you charge them for the service and re-export it back. Temporary Admission At first sight, this also seems to alleviate the VAT and Duty issue, however, I would advise you to take legal financial advice if the goods you are processing are for financial gain before deciding whether Temporary Admission or Inward Processing is most appropriate. Temporary Admission is to facilitate the temporary movement of goods for various reasons but generally where there is no financial gain. The process of applying for Temporary Admission and its operation is very similar to Inward Processing. Outward Processing This authorisation should not be confused with Inward Processing; it is completely different. This authorisation allows you to send your goods temporarily outside of the UK for processing such that no VAT or Duty is payable on re-import on the true value of the goods but only the cost of processing those goods. In the rest of this article, we will consider further the Inward Processing (IP) Authorisation only. How IP works 1. If you are only importing items to process or repair a maximum of three times a year, HMRC allows you to use a process known as Authorisation by Declaration. This means the Application can be done at the time of import for goods valued up to £500,000 for import. HMRC will take a deposit for the VAT and Duty at the time of import usually from a deferment account, this money is only repaid on successful completion of the Bill of Discharge which must be sent to HMRC illustrating when the goods were re-exported with the customs entry numbers. The correct customs procedures codes must be used at both import and export to support this. 2. If a business is importing goods for process or repair more than three times a year, they will need to apply to HMRC for a Full Authorisation. 3. To import goods under this Full Authorisation the business (or their agent) will need to enter the correct customs import information in the HMRC CHIEF system. This is normally done by the customs broker/freight forwarder or fast parcel courier who have a direct interface with the HMRC Chief system. However, it is very important that the ‘importer’ manages this process extremely carefully and sends instructions to the person making the declaration to ensure all information is entered correctly. Instructions should include: a. Reason for import/re-export b. Description and identification numbers c. True value using one of the Customs Valuation rules see HMRC Notice 252 d. Country of origin e. Tariff code f. Weight g. CPC code for import/export h. IP Authorisation Number and Customs Supervising Office. 4. You have a specified time limit to process and re-export the goods on completion. When exporting, similar information to the above will be required along with the export CPC code. 5. Once you have completed the export correctly, it is recommended that you obtain and check the C88/ E2 document at both import and export or check the HMRC MSS data (Management Support System which you need to pay for) to ensure the import and export are completed correctly without errors. If there are errors, you are liable for them. If the errors show the IP process In October 2020 HMRC reaffirmed its position regarding import VAT and who is entitled to reclaim VAT paid on imports under current UK legislation (see Notice Revenue and Customs Brief 15). If you import goods to ‘process’ (testing, measurements, calibration, repair etc) them for financial gain, and you are not the owner of the goods, the notice suggests that only the owner of the asset is entitled to reclaim back the VAT or account for it using Postponed Vat Accounting (PVA). This is clearly an issue for the Test, Measurement and Calibration Industry (TMCI).bmta.co.uk 11 is incomplete, you will be liable for the VAT and any duty on the true value of the goods. 6. Depending on the time period granted in the IP for the import and export of the goods, you will need to complete a Bill of Discharge with HMRC for every item that was imported over the period. This will require specific details from the records of import and subsequent export. IP Application Process To apply for IP, you need to tell HMRC the following: 1. The tariff headers for all the instruments you are going to import over the next five years. There is an issue here because, in TMCI, it is difficult to even approximately predict this. Furthermore, your authorisation is limited to these declared codes so if a customer sends you something that is not covered (you will have a VAT liability), you need to reapply and retrospectively correct the import – not easy. 2. The approximate true value of the goods and how many for each tariff Header over the five years. 3. The economic code of the process and the HMRC supervising office. 4. How long it will take you to process the goods and re- export them. The above are just a few of the questions. Once your authorisation is granted (and you may need a deferment account – not straight forward and usually involves personal guarantees) it will also state what Placement and Discharge customs offices should be used, for example, East Midlands Airport. IP In Practice If you are a major international corporation with your own logistics department, transport systems and links to the HMRC CHIEF system, the IP is workable as you are in complete control. For example, an aircraft engine manufacturer having engines shipped back for overhaul. The value of the overhaul is high, making any cost in administering the IP insignificant and you have total knowledge of the engine’s true value, tariff code, weights etc. You would probably only be completing 100 or so of these high-value events a year. However, if you are an SME you may potentially have some serious problems with the IP system. You will be totally reliant on the Fast Courier networks completing your import clearances on your behalf. Therefore, you should engage with a Customs Broker or Freight Agent who can help with this process, however, in many instances this will not always be possible. Take the TMCI example: • You will be dealing with hundreds if not thousands of ‘low revenue-generating value’ items per year that may carry a high ‘true value’. • You will not necessarily know who is sending something in, from where, how and when. • If you do know what is being shipped, you need an arrangement with the Fast Couriers that they contact you for customs clearance instructions. • If the Fast Couriers do not alert you and ask for clearance instructions, they will import it as a bulk or permanent item, and you will have the unclaimable VAT liability to pay. They will use their judgement according to your customers’ shipping documentation on what information to enter in the HMRC import declaration. • If they do contact you for clearance, you will need to: • Tell them to import under your IP authorisation. • Give them the correct CPC code and your EORI number. • Declare the INCOTERMS and any insurance value on the shipment if applicable. • Declare the description, tariff code, identification, weight and TRUE VALUE of each item.bmta.co.uk 12 • TRUE VALUE. Here is a major issue for most third- party service providers. Firstly, you are responsible for this. You must provide and keep evidence on what value was used and why. In effect, you are expected to know what the value is of potentially thousands of manufacturers’ equipment of which each may have hundreds of product models and many of which have multiple configurations and options that affect the price. Impossible. It is not good enough just to accept the customer’s declared value, they might not know anyway as they may be a third party themselves. It is fraudulent to declare a deliberately low value. Furthermore, there is the complication of; what is the value of an item that could be many years old and obsolete? The biggest issue with this ‘true value’ is that you, as the importer, are liable for it. In arriving at the value, you must use HMRC’s Notice 252 valuation methods. • Note previously, the IP authorisation states where the Placement and Discharge be completed, e.g. East Midlands Airport. You have absolutely no control over this. • Having provided the Fast Couriers with all this information they then have to clear it correctly. • Assuming that the above is achieved, then you will need to re-export within the IP timeframe and instruct the Fast Couriers on how this needs to be done to correctly close out your IP return. This normally involves pre- alerting the Fast Courier by email of the consignment. From experience to date in 2021 since Brexit, we can tell you that the above will not happen without significant errors. A company we work with in TMCI have so far reported 30 IP’s over two months and the Fast Couriers have imported or exported most of them incorrectly. This is despite a controlled Returns Authorisation System being in operation with their customers and very accurate information being supplied for customs clearance. Correcting these mistakes requires the Fast Couriers to amend entries but that is simply not happening because they are overwhelmed. This company now has a VAT liability in the order of several tens of thousands of pounds for a generated revenue from the work of a few thousand pounds unless these errors are corrected. Many businesses may not even be aware of the fact they need to apply for inward processing and may at some point in the future be subject to a HMRC audit whereby they could face significant demands for repayment of VAT and other penalties which could be very costly. 13 bmta.co.uk 13 THE APPLICATION OF FLEXIBLE SCOPES IN ACCREDITATION By Paul Greenwood, Operations Director, UKAS Historically, accreditation was defined by accreditation bodies (UKAS in the United Kingdom) in very precise terms and presented as a fixed scope on the schedule of accreditation; this provided an accurate and unambiguous description of the conformity assessment activities (testing, inspection, certification and so on) covered by an organisation’s accreditation. Over time however, this model has increasingly become considered as restrictive in that it does not readily enable new or modified activities to be added to a conformity assessment body’s (CAB) scope, even when competence has already been demonstrated in similar or associated areas of expertise. Although applications for extension to scope can be submitted to UKAS at any time, the standard timescales required for the subsequent assessment and grant of accreditation may not allow the accredited organisation to respond promptly to swiftly changing market needs. Flexible scopes of accreditation provide a mechanism to allow accredited organisations to undertake new or modified activities within their scope of accreditation, even though the specific conformity assessment activities may not be explicitly stated on the schedule. The degree of flexibility can vary between technical disciplines and conformity assessment activities. Accreditation of a flexible scope inevitably places more responsibility on the accredited body to demonstrate that valid, fit-for-purpose processes and/or activities are undertaken competently, impartially and consistently, and comply with the relevant conformity assessment body standard(s). This does not mean however that an accredited organisation can simply undertake any activity that is requested of it by a client and claim that it is accredited. The bounds of flexibility in the scope of accreditation must be clearly defined and agreed upon between the accreditation body and the accredited organisation, with the CAB demonstrating to UKAS that it has the competence to work within the full range of its flexible scope, as well as having sufficient resources. Details of the flexible scope will be documented on the schedule of accreditation so that end- users of accredited activities are aware of limitations. The boundaries will be dependent on the accreditation maintained, but could include flexibility in specific components of an accredited activity, for example: a) area of activity, products, parameters, product/ process standards, certifications, materials, schemes, sample types b) range of activity, tests/examinations, technical/clinical areas, clustering of scope IAF codes (or part thereof) c) methods, procedures, parameters, equipment, measurement, extent of technical/clinical area, specification d) type of activities undertaken at a location e) commissioning of new locations For example, within some technical sectors, accredited organisations may be required to establish temporary facilities or new locations to serve specific customer needs. To allow activities at these locations to be included within the scope of accreditation without undue delay, UKAS can consider the option of awarding accreditation for adding new locations under a flexible scope, where competence in the activities has already been demonstrated at existing locations and the CAB has a fit-for-purpose methodology for setting up such facilities. Originally, flexible scopes were introduced to improve the agility of accreditation to support testing and calibration laboratories because other conformity assessment body standards already included an element of inherent flexibility. More recently, however, the interest in greater flexibility in areas such as inspection and certification has grown and UKAS has updated its guidance surrounding flexible scopes of accreditation in its document GEN 4 (UKAS policy and general guidance for the implementation and management of flexible scopes of accreditation – Edition 1, October 2019). Organisations interested in applying for flexible scopes should submit a formal application for an extension to scope (available from the UKAS website www.ukas.com) or contact their assessment manager or info@ukas.com to discuss whether the flexible scope mechanism is feasible and appropriate for their organisation and activities. 14 bmta.co.uk 14 SOFT COBOTS FOR SEMI-AUTONOMOUS METROLOGY: TOWARDS INDUSTRY 5.0 By Professor Samia Nefti-Meziani Most of the quality control and metrology solutions used by businesses to provide accurate and reliable measurements of products has, until now, relied heavily on hand-held tools and worker’s dexterity. This is a core issue as the overall performance of the process could be compromised by human error, especially when tasks are performed repeatedly and inconsistently. Moreover, there are some other solutions available for metrology-assisted operations, including fully automated machining cells incorporating metrology tools. A more interesting metrology solution that may be cost-effective for SMEs and could ensure manufacturers’ production performs better is the semi-automated system. It can offer an autonomous parts handling system with integrated inspection but requires a high human intervention level. This can be achieved by solving manipulation problems, automating the absolute measurement and higher repeatability in inspection tasks, to make it an integrated part of the production process. This is where collaborative robots, i.e. cobots, come into play. While current conventional industrial robots prove to be highly effective on the assembly line, they remain heavy and isolated from the humans on the factory floor because they can be dangerous to be around. In contrast, Cobots emerge as a solution to improve the task execution where the human is required. Cobots can provide the necessary force, repetition and accuracy required for tasks, including polishing and measuring. They can be taught manually using Artificial Intelligence to help humans ensure efficiencies and maintain the quality aspects of the product, significantly so when the process’ overall performance is compromised by human error. On the other hand, cobots are a smaller size and easy to move across the shop floor without changing the production layout. They are easy to assemble, take apart and re-task. Their joints are force limited, making them very safe in case of a collision with a person – although their safety approval could be difficult to obtain, especially if the end effectors used present some safety issues. However, the existing cobots also have serious limitations, including the low payloads that they are able to handle (between 3 to 15kg), and their typical speed is roughly considerably less than a traditional industrial robot. In terms of precision, industrial robots can produce faster and more accurate paths for a task than cobots can do, as it is challenging for workers to generate an accurate path of the task’s motion that the cobot would need to perform. In contrast, the new generation of cobots, i.e. soft cobot, with their unconventional elastic materials, take advantage of deformable materials and their intrinsic dynamics to enhance flexibility and controllability. In so doing, this makes them substantially more human-friendly and could potentially overcome the limitations in speed, handling, lifting payload, cost and the accuracy of the existing cobots. However, for soft cobots to be deployed for quality control and metrology tasks, additional steps toward providing a credible alternative to traditional rigid-bodied robots and existing cobots are required. There are still some technical challenges that remain to be addressed. For example: • the ability to modulate stiffness in soft robots is a prerequisite to suit specific tasks (especially when accuracy is required), and despite substantial research, the soft mechanisms proposed to date are still limited and need to be developed further; For UK manufacturing to remain competitive, it is imperative to focus on delivering products efficiently in a cost-effective way without sacrificing quality. bmta.co.uk 15 • soft robots are continuously flexible/deformable. The need to cope with different manufacturing environmental conditions, including humidity, temperature, vibration, and cleanliness, can be constraining factors that mean traditional sensors are inappropriate and advances are needed; • soft robots have demonstrated superior manipulation in some applications compared to conventional systems, but universal soft manipulators capable of handling all products types are still largely missing; • there is also a need for control and architectures that exploit morphological computation and control methods to external and system damage. Addressing these challenges will allow soft cobots to become more compact in size, more accurate, more dexterous, easier to control and more affordable. Professor Samia Nefti-Meziani’s research group has already tackled some of the above challenges by pioneering the first application of this new generation of cobots in manufacturing. Her team has been addressing these challenges since 1990 through prototypes and demonstrators, leading on resilient, soft robots. For example, Professor Samia Nefti-Meziani and Professor Steve Davis recently demonstrated a 40cm soft arm able to lift a weight of 150kg, higher than is typical of soft systems. It addressed the stiffness modulation challenge, advancing soft sensing through the development of a soft skin and integrating sensors into soft actuators. They also developed the first example of a pneumatic muscle able to self-heal and have been active in developing universal soft end effectors for handling all types of objects and payloads. By addressing the above challenges and increasing the UK’s research capacity in this area, we can expect true breakthroughs with enormous importance in the short term in manufacturing. Soft cobots can provide cost-effective technology for SMEs and businesses to increase their productivity, reduce waste and ensure that parts used in aircraft, cars, and trains, for example, can be made more lightweight. This in turn decreases their energy requirements and lowers the amount of CO2 released during operation. Manufacturers will undoubtedly benefit from research in soft cobots that will refine the collaborative interactions between humans and offer low-cost solutions for metrology and inspection tasks. Soft cobots will also present some interesting challenges to the metrology community in developing sensors and measurements techniques. Industry 4.0 has clearly made an impact on manufacturing, but if we want to take deployment, safety, quality, productivity and reliability a step further, we need to look ahead, embrace the next generation of cobots and pave the way to Industry 5.0. For further information please see https://howtorobot.com/expert-insight/pros-and-cons-collaborative-robots-flexibility-vs-efficiency16 bmta.co.uk SOIL ANALYSIS TO ASSESS SOIL HEALTH AND CONTAMINATION By Dr Elinor Hughes, Technical Copywriter at Markes International 16 After reading this lengthy list, it’s not difficult to appreciate Franklin D. Roosevelt’s statement that “the nation that destroys its soil, destroys itself”, a reference to the desertion of farms following the stock market crash of 1929, which caused the “dust bowl” in the Midwestern United States. Yet, despite reports that the health of our soil is under threat from climate change, population growth, urban development, waste, pollution and the demand for more food and crops for bioenergy, soil has been overlooked in UK environment policy in recent decades, according to the Environment Agency (EA).2 In a 2020 summary on the state of the environment, the EA reported that in England and Wales, almost 4 million hectares of soil are at risk of compaction, which affects soil fertility, water resources and increases the risk of flooding. Over 2 million hectares are at risk of erosion. Intensive agriculture has caused arable soils to lose 40 - 60% of their organic carbon, affecting agricultural production and our resilience to climate change. UK soils store about 10 billion tonnes of carbon, which is roughly equal to 80 years of annual UK greenhouse gas emissions. Also, soil degradation was calculated in 2010 to cost £1.2 billion every year.2 The UK government’s 25 Year Environment Plan 3 is set to address some of these issues by tackling soil degradation and improving soil health while developing better information on soil health. Soil health is defined as the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals and humans. To gather data on the health of soil samples, there are two main categories of analysis. One is descriptive indicators, such as soil colour, texture and fertility, which are often used by farmers to understand soil quality. The other is analytical indicators, which are divided into three parts: biological indicators (organic matter, soil biology), chemical indicators (nutrients, acidification, contamination) and physical indicators (compaction, erosion and sealing).1 A chemical soil health investigation typically involves drilling boreholes across a site and taking samples from various depths, which are then sent to a laboratory for analysis. Physical properties may be assessed at the laboratory together with tests for ground gases and vapours (volatile organic compounds or VOCs). VOCs are analysed using a gas chromatograph-mass spectrometer. This provides a graphical readout that can be interpreted to show which VOCs are present and at what ratio in relation to each other. What VOCs can tell us about soil health Soil is teeming with microscopic life, such as bacteria, protozoa, fungi and nematodes and each performs specific functions.4 Some bacteria, for example, are nitrogen-fixing, some form plant galls, some use inorganic substances for energy, and others are decomposers that convert energy from plant litter into forms that are useful for the rest of the soil food web. There is increasing evidence that VOCs play essential roles in communication and competition between soil microorganisms. 5 Unlike other chemical analysis techniques, such as DNA or phospholipid fatty acid tests that use live or dead organic matter to determine which microbes are in a soil sample, VOCs could give a better understanding of which microorganisms are actively metabolising within the soil. However, VOCs in soil are diverse and include a range of compounds including carboxylic acids, alcohols, terpenes, amines, esters and alkenes. 6 Detecting such a wide array across a large concentration range (many VOCs are present at trace levels) in such a complex matrix as soil is challenging. The importance of soil health Soil is vital for our survival. 95% of global food supplies are produced on soil. It reduces flooding, filters water, absorbs and reduces pollutants, regulates our climate and the gases in the atmosphere, provides a habitat for soil-dwelling organisms (some of which aid pest control and pollination), protects cultural heritage, provides a stable platform for buildings, provides raw materials, and it could be the source of new life-saving medicines.117 bmta.co.uk 17 Techniques for extracting soil samples for VOC analysis by gas chromatography-mass spectrometry (GC–MS) can help to overcome the challenge. These are: headspace (in which volatile compounds are extracted from the area directly above a soil sample sealed in a vial), headspace sorptive extraction (in which a probe coated in a sorptive phase is placed in the headspace for a fixed time before analysis), solid-phase microextraction (or SPME, in which a fibre coated with a sorptive phase(s) is used to extract VOCs), in situ extraction (in which a probe containing a sorbent sampling tube is inserted into the ground to gather VOCs by diffusion or pumped sampling) and filtration. Although headspace–solid-phase microextraction (HS–SPME) has been the method of choice for soil sample preparation,7 and detection limits for SPME have been reported to reach parts per trillion (ppt) levels for certain compounds, SPME can be limited in its sensitivity by the amount of phase available on a SPME fiber (~0.5 μL). This leads to competition between analytes for absorption into the phase. This has been overcome by cultivating the microorganisms individually by addition of a substrate to increase the relative concentration of volatiles; 8 however, this can distort the original profile of the soil sample by removing the microorganisms from their normal environment, resulting in misleading interpretations. Increasing the sensitivity of the analysis A recent study has shown that this process can be avoided by overcoming the limitations of a single headspace–SPME extraction with the use of SPME–trap (SPME combined with a sorbent- filled focusing trap, which focuses analytes into a narrow band of gas that is injected into the gas chromatograph) and SPME–trap with multi-step enrichment. 9 This maximises the sensitivity of the analytical technique to enable the detection of low levels of compounds. Maximum sensitivity is something analysts strive for to ensure that even compounds at trace levels can be detected to form a comprehensive VOC profile. In the study, the researchers agitated samples of soil taken from a roadside in vials for one hour before three headspace extractions were taken and fed into the trap and injected into the gas chromatograph in one run (Figure 1). Combining SPME with a focusing trap enhances sensitivity by improving peak shape and allowing splitless analysis of the compounds while extracting the headspace multiple times drives the equilibrium by depleting the headspace of the sample. Figure 1: Workflow for SPME–trap with multi-step enrichment. The extracted headspace volume is injected into an electrically cooled, cryogen-free, multi-sorbent-bed focusing trap where the analytes are refocused and preconcentrated. Following this step, the carrier flow is reversed (‘backflushed’) and the trap is heated rapidly (up to 100°C/s heating rate), transferring the analytes to the GC column in a concentrated band of vapour (~100 µL). The team found that VOCs from a large variety of compound classes (including carboxylic acids, alcohols, terpenes, amines, esters and alkenes) were identified using both SPME–trap and SPME–trap with multi-step enrichment (Figure 2). The most prominent compounds identified in the soil sample were benzaldehyde, n-octanal, cyclosativene, calarene (a compound known to attract organisms to facilitate spore dispersal) and 4,9-muuroladiene. However, while SPME–trap resulted in 544 peaks, SPME–trap with multi-step enrichment delivered a total of 656 peaks. In addition, some compounds could only be detected using multi-step enrichment, for example, dodecanal, a known staphylinid beetle secretion. Without enrichment, an important piece of information about the soil would have been missed.bmta.co.uk 18 Soil sampling for contamination study As well as the state of microorganisms in the soil, VOCs can be used to assess soil contamination. Contaminants can come from agricultural and industrial sources, such as improper waste disposal, leaks from storage tanks and improper treatment of organic waste solvents from chemical plants. VOCs also migrate from the air, groundwater and wastewater into soil. Common contaminants are petroleum hydrocarbons, pesticides and heavy metals such as lead. Cyanide has been found in soil, the chronic inhalation of which affects the central nervous system. Cancer-causing polynuclear aromatic hydrocarbons and BTEX compounds (benzene, toluene, ethylbenzene and xylene) have also been found in soil. BTEX compounds are often detected around roads and other areas affected by emissions from the combustion of petroleum products such as petrol and diesel fuels. They are of concern because they are known carcinogens and endocrine disruptors.10 The clear determination of BTEX compounds within soil is therefore an important factor for environmental monitoring. BTEX compounds have a high affinity with apolar matrices such as soils, making them difficult to monitor, especially at lower levels. 11 Using SPME–trap with multi-step enrichment (roadside soil samples agitated for one hour before being extracted three times), both BTEX compounds and microbial VOCs can be analysed in a single analysis. Multiple extractions lead to much higher responses for BTEX compounds, ensuring clear identification and quantification (Figure 3). Figure 2: (a) VOC profile for a soil sample using SPME–trap and SPME–trap with multi-step enrichment, with the most prominent VOCs numbered: (1) benzaldehyde, (2) n-octanal, (3) cyclosativene, (4) calarene and (5) 4,9-muuroladiene. (b) A close-up of the chromatogram shows an increase in sensitivity from SPME–trap to SPME–trap with multi-step enrichment, in particular for undecane, benzothiazole and 4-(1-methylethyl)benzaldehyde. Figure 3: Peak areas from extracted ion chromatograms for SPME–trap and SPME–trap with multi-step enrichment, indicating the increase in response for the BTEX compounds in soils. 19 bmta.co.uk 19 Conclusions A wide range of VOCs linked to biological functions can be extracted directly from the headspace of soils using solid-phase microextraction (SPME). The sensitivity of SPME can be increased by using focusing trap technology and multi-step enrichment to give a more comprehensive VOC profile for soil health analysis. When using multi-step enrichment, an additional 112 peaks were discovered from a soil sample, in addition to an increased response for contaminants (for example, the BTEX compounds). References 1. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/805926/State_of_ the_environment_soil_report.pdf 2. https://www.gov.uk/government/publications/state-of-the-environment/summary-state-of-the-environment-soil 3. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/693158/25-year- environment-plan.pdf 4. http://nwdistrict.ifas.ufl.edu/phag/2019/04/12/healthy-soil-is-teeming-with-microscopic-life/ 5. K. Schulz-Bohm, H. Zweers, W. de Boer and P. Garbeva, A fragrant neighborhood: volatile mediated bacterial interactions in soil, Frontiers in Microbiology, 2015, 6:1212, doi: 10.3389/fmicb.2015.01212. 6. J. Peñuelas et al., Biogenic volatile emissions from the soil, Plant, Cell Environ., 2014, 37: 1866–1891. 7. L.M. Dubois, P.H. Stefanuto, L. Heudt, J.F. Focant and K.A. Perrault, Characterizing decomposition odor from soil and adipocere samples at a death scene using HS-SPME–GC×GC-HRTOFMS, Forensic Chem., 2018, 8: 11–20. 8. O. Heinemeyer, H. Insam, E.A. Kaiser and G. Walenzik, Soil microbial biomass and respiration measurements: An automated technique based on infra-red gas analysis, Plant Soil, 1989, 116: 191–195. 9. Improving extraction efficiency of SPME on soil samples by using SPME–trap and SPME–trap with multi-step enrichment, Application Note 263, Markes International, 2020. 10. A.L. Bolden, C.F. Kwiatkowski and T. Colborn, New look at BTEX: Are ambient levels a problem? Environ. Sci. Technol., 2015, 49: 5261–5276. 11. D. Orazbayeva, B. Kenessov, J.A. Koziel, D. Nassyrova and N.V. Lyabukhova, Quantification of BTEX in Soil by Headspace SPME–GC–MS Using Combined Standard Addition and Internal Standard Calibration, Chromatographia, 2017, 80: 1249–1256.Next >