Statement of need: Isotope ratio mass spectrometer with integrated dissolved organic carbon analyzer-, gas chromatograph- combustion/pyrolysis furnace

1. Statement of work:

The USGS Woods Hole Coastal and Marine Science Center requires analyses of dissolved organic carbon (DOC) concentration and stable isotope ratios (δ13C-DOC) from seawater and freshwater samples, as well as stable isotope ratios of methane (δ13C-CH4, δD-CH4), and alkanes (δ13C-C2H6, δ13C-C3H8). These measurements are vital to support projects that characterize dissolved and gaseous organics from gas hydrate systems, petroleum systems and living ecosystems. This integrated set of devices will support projects funded by USGS appropriated funds and reimbursable funds from various sources, including the Department of Energy’s Fossil Energy Program, the Deepwater Horizon oil spill settlement, and the National Science Foundation.

To continue supporting ongoing, planned, and future mission critical investigations by the Gas Hydrates and Coastal Ecosystem Environmental Chemistry projects, an isotope ratio mass spectrometer (IRMS) that can measure stable isotope ratios of carbon, nitrogen, and hydrogen and is interfaced as an integrated system with peripheral devices that isolate and convert compounds from a variety of aqueous and gaseous sample types into CO2, nitrogen, and hydrogen is required. Specifically, the required peripheral for quantifying and introducing DOC to the IRMS is a high temperature catalytic combustion unit that converts organic carbon into CO2 and nitrogen. The required peripherals for quantifying and introducing alkanes to the IRMS are a gas chromatograph and combustion/pyrolysis furnace, which separates hydrocarbons and converts them into CO2 and hydrogen.

2. Salient Characteristics/Components:

The integrated high-temperature combustion dissolved organic carbon analyzer-, gas chromatograph-combustion/pyrolysis furnace- isotope ratio mass spectrometer system must have the following salient characteristics and components:

• An isotope ratio mass spectrometer (IRMS) that can measure up to mass 96 amu, including carbon, nitrogen, and hydrogen isotopes.

o The IRMS must include an electron ionization (EI) gas source, electromagnet, universal triple collector, and hydrogen collector (employing faraday collectors).

o The IRMS must be interfaced with a continuous flow interface system that can dilute samples and interface up to five peripheral “inlet” systems.

o TOC/TNb and GC sample gases must each be selectively dried; i.e. separate NafionTM (or equivalent polymer) drying membranes for EA and GC, and drying to occur only on gas which will be transferred to IRMS, to maintain longevity of drying unit.

o The IRMS must be able to measure up to 10 simultaneous, user-defined ion beams.

o The IRMS must have sufficient amplification (100V) to measure parallel ion beam amplitudes with a large dynamic range within the same analysis.

o The IRMS must have an electron impact ion source with a self-aligning filament.

o The ionization filament must be coated with thorium, or an equivalent coating, to improve longevity.

o The IRMS internal precision specifications (based on standard deviation of fit of reference gas pulses) must be demonstrated at instillation and should be:

δ13C : ≤ 0.06 ‰ (n = 10 x CO2 gas pulse @ c. 10 nA) δ15N: ≤ 0.06 ‰ (n = 10 x CO2 gas pulse @ c. 10 nA) δD should be: ≤ 0.20 ‰ (n = 10 x H2 gas pulse @ c. 10 nA) o The IRMS must use only single-phase 120V or 230-240V connection to mains power, (i.e. must not use 3-phase 400V connection for power), to ensure minimal remodeling of laboratory facilities is required o The IRMS must be bench-top and no larger than 600 Width x 500 Depth x 650 Height to be compatible with USGS lab space availability.

o The analyzer unit should be constructed of high-grade stainless steel and polished internally to UHV design criteria., to ensure minimal memory effects.

o The analyzer unit should feature intrinsically high vacuum conductance, designed for optimal abundance sensitivity performance without requiring differential pumping; i.e. it should require only a single turbo molecular pump to reach optimal vacuum (> 1 x 10-7 mBar) - within 6 hours of pumping, for minimal maintenance down-time and minimal cost of lifetime ownership.

o The gas handling (i.e. monitoring/reference gas, helium, and gas from peripherals) system must be integrated into the chassis of instrument, not housed in a separate unit, for efficient use of space and minimum lengths of transfer capillaries.

o The gas handling/management system must employ dedicated Digital Mass Flow Controllers to enable full software control of monitoring/reference gases, and dilution of high-flow inlet gases o The IRMS must come with software available to permit hardware control, real-time data viewing, and generation of data reports.

o It should be possible to perform all standard instrument quality checks without any physical contact with the instrument, i.e. system must automate system-ready procedures such as linearity checking, stability checking, tuning, H3

+ factor calculation and correction, and allow scheduling of these checks within acquisition queues.

o Digital Mass Flow controllers must be able to be calibrated within the software to enable operators to define desired amplitude of monitoring gases within methods (from 0 to 100 nA or equivalent, i.e. across the entire dynamic range of possible measurement; it must be possible to define any nA height desired within this range in a non-incremental fashion, i.e. must not use a step-wise series of restrictions to achieve different dilutions/gas pressures.

o The IRMS should have a fully interlocked fail-safe high vacuum system with automatic isolation of the source in the event of power failure, and automatic restart upon return of power, to ensure protection of system in event of power failure.

o The IRMS software must be installed on a USGS-furnished computer with the following specifications: compatible with Windows 11 Pro Operating System, i5, 16GB RAM, 512 GB

SSD.

o The IRMS must be fully compatible with peripheral devices included on this SON.

o The IRMS must come with 1 year of instrument consumables.

• A high-temperature (up to 950℃) combustion total carbon (TC) and total nitrogen (TN) analyzer that can specifically measure stable carbon and nitrogen isotopes and concentrations of total dissolved/aqueous organic carbon (TOC) and total dissolved/aqueous bound nitrogen (TNb) in aqueous samples. The TOC/TNb analyzer should not use chemical and/or UV oxidation techniques.

o The analyzer must directly physically integrate with the isotope ratio mass spectrometer to enable stable isotope analysis. This includes using compatible carrier gas (He), plumbing between the analyzer output and the IRMS input for direct measurement of δ13C-TOC and δ15N-total bound nitrogen.

o The analyzer must allow dosing of O2 withing the reactor system to promote complete combustion of samples.

o The TOC/TNb analyzer should be fully supported by the IRMS manufacturer o The device must also be able to measure carbon and/or nitrogen concentration of aqueous samples o The software that controls the TC/TN must also control the IRMS to permit seamless and integrated operation of both devices. Consolidation of the elemental composition and stable isotope results should be performed through the IRMS control software.

o The system should feature computer-controlled leak check function with leak site diagnostics.

o The analyzer-IRMS integrated system must be able to resolve δ13C of aqueous organic carbon to a precision of 0.1‰ (demonstrated at installation by analysis of 10 injections of caffeine at 43ppm C).

o It should be possible to measure δ13C, δ15N and %C within the same analytical measurement from a single sample injection. It should also alternatively be possible to measure δ13C, %C and %N within the same analytical measurement from a single sample injection.

o The analyzer must include an autosampler with a capacity of at least 30 vials (40mL “volatile organic analysis” style vials). The autosampler should not be sealed during analysis, to allow samples to be added during operation.

o The analyzer must be able to measure aqueous sample injection volumes between 200µL to 3 mL, with injection volumes defined by the user in the software methods for any individual injection.

o Aqueous carbon concentration measurements should be performed within a runtime of 5 minutes.

o The analyzer must be able to determine DOC concentration to a precision of <2% RSD.

o The analyzer must include a high sensitivity CO2 infrared detector.

o The analyzer must be able to function both as a peripheral to the IRMS and as a standalone instrument.

o The analyzer must have technology to reduce damage to the reactor by salt in marine samples via a removable/replaceable receptacle which is installed in the hot zone of the reactor, which serves as a barrier between the sample and the reactor reagents.

o The system must include accessories to pre-concentrate CO2 on a solid matrix after combustion and release CO2 by rapid thermal desorption that does not impart stable isotopic fractionation.

o The system should be configurable with separate combustion and reduction column slots, to allow installation of a reduction column for the conversion of NOx to N2 for δ15N stable isotope analysis. It should also be possible to perform analysis without the reduction column installed, to enable %N to be determined from the measurement of NO by IR detection instead.

o The integrated high temperature combustion – IRMS system must have demonstrated ability to measure δ13C-DOC for samples with DOC concentrations of XX ppm.

• A gas chromatograph (GC) – combustion/pyrolysis furnace interface system to compound-specific stable isotope measurements of light n-alkane hydrocarbons (nC1-nC5) and organic biomarker compounds using a single software interface for full GC-IRMS analysis.

o The gas chromatograph with interface unit must permanently connect to the same IRMS as the TC/TN analyzer without physical changing of connections required to interface wither peripheral to the IRMS. It must be possible to switch between the inlets from within the software.

o The gas chromatograph must include a split/splitless (SSL) inlet enabling split ratio injections up to 7,500:1.

o The gas chromatograph must have a flame ionization detector (FID).

o There must be a “heart-cutting” eluent diversion mechanism to direct the eluent between the FID and the combustion/pyrolysis interface unit connected to the IRMS which provides 100% diversion from one or the other; it does not employ a “backflush” mechanism which loses eluent to the inactive pathway.

o The gas chromatograph must be compatible with commercially available capillary and packed columns (e.g., a 30m porous layer open tubular column).

o The gas chromatograph must also be compatible with programmable temperature vaporization (PTV) and cold on column (COC) inlets (and must enable at least 2 inlets to be installed at the same time).

o The gas chromatograph must support up to 20 oven ramps with 21 plateaus, and allow negative temperature ramps; the maximum achievable temperature ramp should be ≥ 120°C/min. The oven must operate up to 450℃, and should be compatible with a cryogenic oven cooling feature.

o The gas chromatograph oven cool down from 450℃ to 50℃ should be <4 minutes at STP.

o The total GC-IRMS analysis must exhibit peak broadening no greater than 1% (i.e. analyte peak should not broaden more than 1% through the GC and reactor interface, into the IRMS).

o The gas chromatograph must have a peak area repeatability <1%RSD and retention time repeatability <0.008%.

o The system should be capable of δD compound-specific isotope analysis by pyrolysis/thermal conversion when configured with either a hollow ceramic reactor operating at 1450℃, or a quartz reactor packed with a chromium catalyst operating at 1100℃. The manufacturer should provide advice for defining which reactor is most appropriate for specific applications.

o The ceramic reactor should be relatively thick and robust to minimize potential for damage, as well as protect against leakage upon ceramic becoming more porous following extended temperature cycling.

o The system should be capable of δ13C compound-specific isotope analysis by combustion of GC eluent when configured with either a quartz reactor packed with CuO pellets operating at 850°C, or a quartz reactor packed with twisted NiCr, Pt & Cu wires operating at 950°C. The manufacturer should provide advice for defining which reactor is most appropriate for specific applications. The manufacturer should provide examples of extended capacity/longevity of the oxidative capacity of the reactor, e.g. extended unattended analyses without loss in performance.

Evaluation of data provided will be based on comparison of data provided, including evaluation of precisions, length of analysis time, drift, comparability or results from beginning to end of analysis. If data meeting this requirement is not available, please provide the best nearest equivalent for evaluation.

o In particular, the manufacturer should supply:

an example dataset demonstrating reliability of δ13C analysis on a target analyte (can be a single compound) from beginning to end of an unattended analytical run of at least 100 consecutive measurements (i.e. no maintenance or re-oxidation protocols throughout the run), which has loaded the reactor with at least 50 µg of carbon in total across the entire experiment. Overall precision should be equal to or better than standard installation specifications, without employing drift corrections.

An example of extended unattended analysis (i.e. > 100 consecutive runs totaling > 60 hours analysis time) of more challenging analytes, e.g. functionalized biological compounds. Excellent precision (i.e. equal to or better than installation specifications) should be evident on multiple compounds Data should include results for at least 4 different compounds with at least 40 replicate measurements of each compound within the entire analytical run). Repeatability of measurement of the same compounds demonstrated throughout the entire acquisition should be demonstrated without drift corrections. Again, total analysis should not include any maintenance or assisted re-oxidation of the reactor – analysis should be continuous.

o Reactors should ideally be at least 600mm in length for optimal capacity and extended hot zone.

o The combustion furnace should include an automated/programmable O2 dosing system, which can be configured either for periodic regeneration of the reactor, or continuous dosing during analysis, to allow for flexible approaches to reactor regeneration and optimal maintenance of combustion chemistry.

o The gas chromatograph split/splitless inlet should allow injection of samples by manual or automated syringe injection.

o The gas chromatograph system should provide exceptional linear performance across a broad range of concentrations of analyte; The provider should give an example of data showing at least a 250 fold range of concentrations of compound analyzed, maintaining a precision ≤ 0.4‰ (or best nearest equivalent).

o External analytical precision for GC-IRMS analysis (i.e. analytical precision of measurement of organic compounds introduced to GC and analyzed by GC-IRMS) must be demonstrated at installation on a range of compound classes, not only n-alkanes; e.g. must include demonstration of specifications using a mix including fatty acid methyl ester, nicotine, as well as 2 n-alkanes (or an equivalent mix of at least 4 compounds in at least 3 different compound classes).

Specification (1σ) for δ13C should be: ≤ 0.20 ‰ (n = 10 injections of mix, all 4 compounds) Specification (1σ) for δD should be: ≤ 3.0 ‰ (n = 10 injections of mix, all 4 compounds) The GC-IRMS system must be able to switch from δ13C mode to δD mode (or δD mode to δ13C mode) and be conditioned/settled and producing data within standard precision specifications within the space of 2 hours between switches or less. The supplier must provide example data and/or literature evidence in support of this. If data meeting this requirement is not available, please provide the best nearest equivalent for evaluation.

• Additional software specifications:

o Software should feature intuitive data search functions to enable the operator to rapidly filter and search for data, e.g. filter isotopic standards over user definable time scales to simply evaluate instrument performance, or search for specific data sets to produce reports. The search functionality should be able to search local and network drives at the same time.

o User should see immediate, real-time illustration of sample and monitoring gas peak integration with visible baseline detection when acquiring data.

o Control of the entire acquisition system should be done from a single task list o The task list should be editable during analysis (i.e., not “locked” while the system is running) o It should be possible to define standard operating procedures for sample analysis and invoke the stored standard operating procedures with a single mouse click.

o The software should include standard methods for different sample matrices with all relevant parameters pre-defined.

o Instrument control should be done primarily as “event based” rather than “time based” for reduced possibility of errors due to miss-timing of events.

o It should be possible to import any raw stable isotope data from any manufacturer’s instrumentation into the software to allow universal data processing capabilities and consolidation of collaborative data sets.

o Software must provide automatic, multi-point isotopic calibration derived from analysis of isotope reference materials, and output sample delta values with respect to internationally accepted reference scales. It must allow users to define in-house standards as well as primary and secondary isotope reference materials source elsewhere.

o Software should provide functionality for automatic drift and blank corrections if required. Drift correction should be possible between definable sample groups within an analytical sequence.

o It should be possible to set-up additional mathematical calculations to automate post-analysis data interpretation, such as compound-to-compound variation. It should be possible to define conditional color-coding for easy distinction of results (e.g. for flagging pass/fail results) o All data processing should be done entirely within the instrument software and there should be no pre-requisites for any other spreadsheet software to undertake most standard data processing tasks, e.g. review calibrated results, calculate mean average and standard deviations of replicate measurements, or to compare calibrated and uncalibrated results.

o It should be possible to create and edit instrument control methods using a simple to understand graphical user interface, such as a flow chart.

o Data processing reports should be exportable to excel and PDF, and include options to include all individual data evaluations or a batch overview, and whether to include or exclude individual chromatograms.

o Software should include intelligent peak labelling across multiple injections/similar samples, and allow injections to be grouped for processing, to make handling of large GC-IRMS datasets simple and quick with batch statistics of all compounds calculated in real-time.

o Software should feature ability to import/export other parameters, such as peak labelling parameters, screen layouts, and calculated columns.

o Software should allow isotope standards to be predefined within a task list (once information on that standard has been entered into a standards database), and then allow user to define that a calibration is then performed on-the-fly in real-time during acquisition, such that real-time data reporting is calibrated.

3. Applicable documents

A quote from Elementar Americas Inc. (Ronkonkoma, NY, USA) is included.

4. Deliverables

The vendor will deliver, install, and certify the integrated dissolved organic carbon analyzer-, gas chromatograph- combustion oven- isotope ratio mass spectrometer at the USGS Woods Hole Coastal and Marine Science Center. The vendor will also install software on the provided PC and demonstrate proper instrument control and data acquisition. The vendor will provide training for software use, routine maintenance, and trouble shooting.