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My CartFAQ Documentation—Measurement Unit Conversion
Q01: | What is the conversion relationship between M and mol/l? |
A01: | M is equivalent to mol/l, mM stands for mmol/l, μM represents μmol/l, nM denotes nmol/l, pM signifies pmol/l, and fM means fmol/l. Specifically, 1M = 103mM = 10?μM = 10?nM = 1012pM = 101?fM. |
Q02: | What is the exact temperature range considered as "room temperature" in experimental operations? |
A02: | In biological experiments, room temperature typically refers to a range of 20-25℃, rather than the actual indoor temperature. |
Q03: | How to convert centrifugal force (×g) to revolutions per minute (rpm)? |
A03: | There are two ways to express rotational speed: centrifugal force (×g) and revolutions per minute (rpm). Some centrifuges have both rpm and ×g displays, but standard centrifuges do not have automatic switching capabilities. The following formula is used for conversion: g = r × 11.18 × 10?? × rpm2 (r is the effective centrifuge radius, measured in centimeters, from the axis of the centrifuge to the center of the sample). For example, at a speed of 3000 rpm with an effective centrifuge radius of 10 cm, the centrifugal force is calculated as: 10 × 11.18 × 10?? × 30002 = 1006.2 (×g). |
Q04: | Can frozen reagents or samples be thawed at room temperature or in a 37℃ water bath? |
A04: | When thawing frozen reagents or samples, if time permits, it is recommended to thaw them slowly in an ice bath or iced water bath. If time is limited, most frozen reagents or samples can be thawed at room temperature or in a 37℃ water bath (though some products, such as certain antibiotics, are not recommended for thawing in a 37℃ water bath). However, caution must be exercised by observing, gently shaking, and monitoring the thawing process. Once partially thawed, they should be removed from the water bath to ensure that the temperature remains close to 0℃ during the thawing process. If the reagent or sample does not freeze at 0℃, it can be placed in an ice bath or iced water bath after thawing. |
Q05: | How to Measure Trace Amounts of Liquid Reagents? |
A05: | 1,Prior to opening centrifuge tubes containing trace reagents, it is advisable to centrifuge them briefly (5 seconds at 500-2000 rpm). This crucial step aims to collect reagents that may have adhered to the tube wall and cap due to transportation or handling, ensuring they are at the bottom of the tube for use. 2,To minimize unnecessary loss, the aliquoting of trace liquid samples should be minimized. Each additional aliquot can result in a loss of 0.5 to several microliters of reagent. For instance, when working with a total volume of 100 μl, dispensing 5 μl at a time usually does not necessitate 20 aliquots. 3, Precalculate the number of samples and the required reagent volumes. Prepare a sufficient amount of working solution in one go and then dispense it into individual reaction tubes. This approach reduces the frequency of reagent aliquoting. 4, It is preferable to use calibrated, high-precision micropipettes and tips with an appropriate volume range, as deviations can lead to unexpected errors and losses. When performing consecutive dispenses, replace the pipette tip after each dispense to prevent significant overdispensing caused by residue from the previous dispense. 5, When aspirating with a pipette, insert it vertically into the liquid surface a few millimeters deep. Avoid inserting the tip directly to the bottom of the tube; positioning it slightly below the surface is sufficient to prevent excessive adhesion of reagent to the tip. Aspirate slowly and release the control button gradually to prevent rapid liquid entry into the pipette tip, which can cause a backflow of a small amount of liquid into the pipette body, resulting in reduced dispensed volume. (6)When dispensing the liquid, position the pipette tip against the wall of the container at an angle and release the liquid slowly. This ensures a controlled and gradual release of the liquid, minimizing any potential splashing or loss. |
Q06: | How to properly handle and utilize trace powder reagents? |
A06: | 1,Prior to opening a centrifuge tube containing trace powder reagents, centrifuge it briefly (5 seconds at 500-2000 rpm). This step ensures that reagent adhering to the tube wall and cap during transportation is collected at the bottom for use. 2,For solid samples weighing 10mg or less, it is generally not recommended to use a balance for measurement but rather to directly prepare the solution according to the amount indicated on the product label. For example, while it may be difficult to extract all 5mg of powder from the tube, it can be fully dissolved within the tube. For slightly larger amounts of trace powder samples, minimize weighing frequency, with each weighing ideally not less than 10mg. Frequent micro-weighing may introduce errors that skew test results. If solution stability is not a concern, it is advisable to prepare all powder reagents in one go according to their labeled doses. 3,If weighing is necessary, use a high-sensitivity analytical balance and calibrate it before use. Avoid wearing latex gloves (opt for disposable polyethylene gloves) during weighing to prevent electrostatic interference between the gloves and weighing paper, which can compromise accuracy. Wearing latex gloves is not recommended for weighing 20-30mg or less, as various tested latex gloves (including some imported brands) can generate static electricity upon contact with weighing paper, causing errors of up to several milligrams. In contrast, polyethylene gloves (similar to cling film material) do not generate static electricity when in contact with weighing paper, resulting in smaller errors. |