Question 1

Where are the best places along the production line to inspect baked goods and snack products?

Accepted Answer

There are several points in the baked goods/snack foods production process that benefit from food safety inspection using metal detectors (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/metal-detectors.html), X-ray inspection (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/x-ray-detection-inspection-systems.html), or checkweighing (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/checkweighers.html)technology. They are listed below:

1. Incoming ingredients. Most of the larger bakers demand that their vendors meet specific HACCP objectives. They may require that metal detectors be used, provide proof of inspection, etc. Even with those methodologies in place, some will also inspect incoming ingredients. Typical incoming inspection consists of drop through and bulk flow metal detectors.

2. Dough stage. Before the product is baked or otherwise processed, this is an ideal location to conduct upstream inspection. Metal detectors are the equipment of choice because metal-based packaging is not part of the process at this stage. Bar products are another example. They can be examined right after sheeting, or after the individual bars are cut, or before the product goes into the wrapper. Alternatively, they can also be inspected after packaging.

3. After baking/before packaging. The inspection equipment type will depend on the product type and whether or not its formulation creates a “product effect”. Warm, moist, high salt content products such as breads are more suited toward X-ray equipment, while metal detectors perform well with typically-inert snack foods. Checkweighers can also be located at this stage to make sure that the product weight falls within the min/max specifications and will not create problems (such as line stoppages due to oversize) at the packaging stage. Checkweighers can also be used to confirm that all of the late-stage filling components, such as icing and other toppings, have been properly dispensed.

4. After packaging. The recommended inspection equipment type is dependent on the packaging material or combination of materials that have been selected for this product. Metal components such as aluminum foil trays or metalized firm structures are much more suited to X-ray inspection. Flexible materials without a metal component, paperboard folding cartons and/or a combination of the two, work very well with metal detectors. Checkweighers are frequently located at this stage of the operation.

5. After case packing. Some bakers or processors prefer to inspect after the final packaging stage: case packing. This is typically done via X-ray inspection, provided that the unit is large enough to accompany a case. In addition to inspection, the X-ray system's ability to detect missing pieces will help ensure that the specified count has been loaded into the case. In certain situations, especially when X-ray inspection is not included at the end of the line, checkweighers are placed here to ensure that the proper number of packages are contained inside the case.

Question 2

What is the best inspection technology to find broken or missing pieces in snack bags?

Accepted Answer

In the case of snack bars and other similar snack products, food X-ray inspection (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/x-ray-detection-inspection-systems.html) can be used for spotting missing or broken pieces.

Question 3

What is the best inspection technology for snacks in metalized film packaging?

Accepted Answer

Although most snack foods don't have the “product effect” issues found in baked items, spotting contaminants is challenged by the packaging material of choice. The majority of snack foods marketed today are packaged in metalized film which is formed into a bag via a form-fill-seal (f/f/s) machine or flow wrapper. This means that these packages are not good candidates for metal detectors. Rejection of products in the food metal detector equipment is also challenging because packages tend to be small. With these process and material obstacles in place, food X-ray inspection equipment (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/x-ray-detection-inspection-systems.html) is the ideal solution to address snack food inspection challenges.

Question 4

What is the best inspection technology for frozen baked goods?

Accepted Answer

Food metal detectors (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/metal-detectors.html) work extremely well with frozen baked goods which no longer have a product effect that “just out of the oven” versions do. The challenge is to make sure that the freezer is efficient and is holding the product at the correct temperature. If a product isn't completely frozen, its unfrozen center will have a tendency to look like a piece of metal to the detector.

In addition, many cake and pie products are frozen immediately after production, so some bakers choose to inspect after the items are case packed using food X-ray inspection (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/x-ray-detection-inspection-systems.html) equipment that can accommodate the case size.

Question 5

Which is the best DNA or RNA quantification instrument?

Accepted Answer

All of the DNA instruments offered by Thermo Fisher Scientific are of excellent quality. To find the right instrument to quantify DNA or RNA in your lab, explore the detailed comparison of UV-Vis spectrophotometers and fluorometers. Things like sensitivity, throughput and budget may be initial considerations when selecting a DNA quantification instrument. You may also consider whether you need target specificity, sample purity information, RNA quality information, or broad dynamic range.

Find additional tips, troubleshooting help, and resources within our Nucleic Acid Quantification Support Center.

Question 6

What is the difference between UV and fluorescence DNA quantification? Which DNA quantification technology should I choose?

Accepted Answer

UV and fluorescence technologies work differently to quantify DNA. UV quantification relies on the intrinsic absorptivity of DNA and RNA molecules, while fluorescence quantification uses dyes that specifically bind to your molecule of choice. With UV technology, quantification isn't as sensitive, but it has a broader dynamic range and also gives data about sample purity‒plus it is faster because there is no reagent prep. With fluorescence technology you get higher sensitivity and molecule-specific data, but it has lower dynamic range and reagent prep is required. The technology you need will depend on what features are important for your lab and experimentation.

Find additional tips, troubleshooting help, and resources within our Nucleic Acid Quantification Support Center.

Question 7

Why is the turbomolecular pump not operating when using Orbitrap Exactive or Q Exactive mass spectrometry instruments?

Accepted Answer

A turbomolecular pump may be switched off because of one of the following reasons:

- Turbomolecular pump is blocked
- Failure of fans in turbomolecular pump
Each of the above reasons might lead to an overheating of the pump. When overheated, a turbomolecular pump switches off automatically to prevent its destruction. This overheating protection prevents the outbreak of a fire and minimizes the risk of destructing the pump.

If the Exactive Series mass spectrometer does not work as expected, use the Tune software for error diagnosis:
- The instrument status window displays real-time status information for the instrument components. All parameters are arranged in a tree view. In addition to showing numerical values of parameters (for example, pump speeds or component temperatures), the instrument status window uses icons to indicate the statuses of system components.
- The messages window displays real-time information about the statuses of the instrument, the control service, or other programs. It might display additional information.

In case of an overheated turbomolecular pump, shut down the mass spectrometer as described on page 6-8 of the manual (https://assets.thermofisher.com/TFS-Assets/CMD/manuals/man-bre0012255-exactive-series-manbre0012255-en.pdf). To prevent permanent damage to components of the Exactive Series mass spectrometer, Thermo Fisher Scientific recommends that you call a Thermo Fisher Scientific field service engineer.

Find additional tips, troubleshooting help, and resources within our Mass Spectrometry Support Center.

Question 8

Why is the temperature of UHV chamber higher than expected when using Orbitrap Exactive or Q Exactive mass spectrometry instruments?

Accepted Answer

The UHV chamber heating control may have failed. During general operation of the mass spectrometer, the temperature of the UHV chamber is not regulated. Only during a system bakeout, electric power is supplied to the heating elements of the UHV chamber. The heating always operates at maximum power. Thus, failure of the heating control does not lead to a dangerous overheating of the mass spectrometer. If the Exactive Series mass spectrometer does not work as expected, use the Tune software for error diagnosis:

- The messages window displays real-time information about the statuses of the instrument, the control service, or other programs. If the heating was terminated, the window displays a corresponding error message.

In case of a failure of the UHV chamber heating control, shut down the mass spectrometer as described on page 6-8 of the manual (https://assets.thermofisher.com/TFS-Assets/CMD/manuals/man-bre0012255-exactive-series-manbre0012255-en.pdf). To prevent permanent damage to components of the Exactive Series mass spectrometer, Thermo Fisher Scientific recommends that you call a Thermo Fisher Scientific field service engineer.

Find additional tips, troubleshooting help, and resources within our Mass Spectrometry Support Center.

Question 9

When using Orbitrap Exactive or Q Exactive mass spectrometry instruments, why does the tune software show bad vacuum?

Accepted Answer

Here are possible causes and solutions:
-System was vented because of a main power failure: A main power failure has the same consequence as switching off with the main power circuit breaker switch. If the power is available again, the system is started up automatically: the pumps are switched on and the vacuum is created. If the system has been vented during the mains failure, it is necessary to bake out the system to obtain the operating vacuum. See “Baking Out the System” on page 8-12 of the manual. If the log file of the data system shows a reboot of the system and the pressure reading in the Tune software shows a bad vacuum, this indicates that the system was vented. In case of frequent but short power failures, we recommend that you install an uninterruptible power supply (UPS). If main power failures occur frequently while the system is not attended (for example, in the night), we recommend that you install a power fail detector. - Vacuum leak: Refer to pages 7-5 and 8-12 in the Operator's Manual (https://assets.thermofisher.com/TFS-Assets/CMD/manuals/man-bre0012255-exactive-series-manbre0012255-en.pdf).

Find additional tips, troubleshooting help, and resources within our Mass Spectrometry Support Center.

Question 10

Why does the metal needle insert in the heated ESI probe frequently clog when using Orbitrap Exactive or Q Exactive mass spectrometry instruments?

Accepted Answer

Clogging of the H-ESI spray needle is generally caused by the presence of non-volatile components in the injected samples. If the non-volatile components of the samples are not removed during sample preparation, they will be injected onto the column where they will gradually bleed off over time into the detector. They may also be directly introduced by the use of non-volatile buffers in the mobile phase. Non volatile buffers should be avoided in LC-MS analysis because the spray needle will clog frequently and in addition the MS optics will quickly become contaminated.

Clogging issues may be worsened when using a divert valve or bypass valve. This is because when the valve switches to waste the LC flow to the needle is stopped, causing the residual liquid in the hot needle to quickly evaporate. This in turn causes the non-volatile components to deposit on the inner wall of the tubing which will eventually clog it.

When using a divert or bypass valve, the issue may be fully resolved by adding another HPLC pump to supply make-up flow through the needle when the column eluent is bypassed. The second pump is connected to the divert valve or bypass valve so that when the eluent is diverted to waste, clean solvent flows through the needle to help keep it clean. Alternatively, sample preparation procedures should be modified to reduce the amount of non-volatile components in each sample injection.

Find additional tips, troubleshooting help, and resources within our Mass Spectrometry Support Center.

Question 11

What is High Energy Collision Dissociation (HCD) as it relates to Orbitrap Exactive or Q Exactive mass spectrometry instruments?

Accepted Answer

The HCD Cell consists of a straight multipole (octapole) device mounted within a metal tube. The metal tube is in turn connected to the C-Trap in direct line of sight.

The voltage offset between the C-Trap and the HCD Cell is used to accelerate the precursor ions into the gas filled cell. Inside the HCD cell, ions collide with the neutral gas causing rotation, stretching and ultimately cleaving bonds to create fragment ions and neutral species, which are subsequently removed by the vacuum system.

The generated fragment or product ions are then pushed back toward the C-Trap and focused before being pushed toward the Orbitrap analyzer.

Find additional tips, troubleshooting help, and resources within our Mass Spectrometry Support Center.

Question 12

What is AGC as it relates to Orbitrap Exactive or Q Exactive mass spectrometry instruments?

Accepted Answer

AGC stands for Automatic Gain Control.

The Automatic Gain Control alters the number of ions in the Orbitrap by filling the C-trap for a calculated period of time. This way, ions can enter the mass analyzer at specified times only.

The ions are gated in the C-Trap and compressed into a narrow cloud before being pushed out to the Orbitrap. The AGC is calculated and during the injection time is when the ions can pass into the C-Trap. Hence, Ion “gating” occurs by changing the polarity of the split lens after the first multipole.

Depending on the experiment and other instrument parameters, the AGC is calculated in three different ways:

AGC Calculated with a Prescan:
When the system is performing the first scan of the run, the instrument will perform a Prescan to calculate the number of ions at that time and to adjust the injection time for the analytical scan accordingly. This is achieved by opening the trap for 1 ms and by performing an acquisition in the Orbitrap (~200 ms).

AGC Calculate on a Scan-to-Scan basis: When two consecutive full scans are acquired within 400 ms, the instrument will use the previous Full Scan TIC to adjust the injection time.

pAGC (predictive AGC): When the method is setup to perform data dependent MS experiments, the dependent scans will use their master scan (Full Scan) as a reference for the AGC calculation.

Find additional tips, troubleshooting help, and resources within our Mass Spectrometry Support Center.

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