Francesco Bertolami 22 d ago

Activate QC parameters in METHOD drop down menù. Select noise and drift and set critiria. Normally i use ASTM for noise and save the method, then start a run without injection (-1 in the batch vial position). In the browser open the data file, drag over the method. In a drop down menù you find execute QC and noise drift report in created with resulta pass o fail. there are other method to obtail noise drift calculation in labsolutions software but this is the simplest

hari patchamatla 15 d ago

In Lab solutions to calculate signal by noise ratio first integrate blank and use the option in integration parameters select the option of signal and drift select the usp not astmand save.
after blank integrate the analyte and keep the spectral reference data of blank it automatically provide the s/N

Calebbuzy1 1 m ago

mostly caused by poor column. maybe you probably injected too much sample which exceeded the capacity of the column.

Kashvenaa Santhiran 29 d ago

but im using a new column.. just few injections

hari patchamatla 15 d ago

if you r using new columns the wrong standard preparation and in few cases if system is not in good condition.

Alan Cervantes 1 m ago

Mode: LC
Detector: UV 266 nm
Column: 4.1-mm x 25-cm; packing L21
Column temperature: 35°
Flow rate: 1 mL/min
Injection size: 50 uL
System suitability
Sample: Standard solution
Suitability requirements
Capacity factor: NLT 2.0
Reiative standard deviation: NMT 2.0% for replicate
injections
Analysis
Samples: Standard solution, Sample solution, and Blank
Calculate the percentage of the label claim in the portion
of C4H13NO7P2 taken:


Result =(r u/rs) x (Cs/Cu) > (Mr1/M2) x 100


ru peak area from the Sample solution
rs peak area from the Standard solution
Cs concentration of anhydrous USP Alendronate
Sodium RS in the Štandard stock solution
(mg/mL)
Cy nominal concentration of alendronic acid in the
Sample stock solution (mg/mL)
Mni molecular weight of alendronic acid, 249.10
Mi2 = molecular weight of anhydrous alendronate
sodium, 271.09
Acceptance criteria: C4H12NNaO7P2 equivalent to
90.6%~110.0% of the labeled amount of C 4H13NO7P2

Alan Cervantes 1 m ago

Use alendronic acid USP MONOGRAPH

ASSAY
• PROCEDURE
Solution A: 14.7 g/L of sodium citrate dihydrate and 7.05
g/L of anhydrous dibasic sodium phosphate in water.
[NOTE-Adjust with phosphoric acid to a pH of 8.0 before
bringing the solution to volume.]
Solution B: 38.1 g/L of sodium borate in water
Solution C: 1 mg/mL of 9-fluorenylmethyl chloroformate in
acetonitrile. [NOTE--Prepare this solution fresh just before
use.]
Mobile phase: Acetonitrile, methanol, and Solution A
(20:5:75)
Diluent: 29.4 g/L of sodium citrate dihydrate in water
Standard stock solution: 0.03 mg/mL of anhydrous alen-
dronate sodium in Diluent, from USP Alendronate Sodium RS
Standard solution: Transfer 5.0 mL of the Standard stock
solution to a 50-mL polypropylene screw-cap centrifuge tube
containing 5 mL of Solution B, and mix for 3 min. Add mL
of Solution C, and agitate for 30 s. Allow the solution to
stand at room temperature for 25 min. Add 25 mL of meth-
ylene chloride, and agitate for 40 s. Centrifuge the mixture
for 10 min. Use the clear upper aqueous layer.
Sample stock solution: Transfer NLT 10 Tablets to a 1000-
mL'volumetric flask. Add 500 mL of Diluent, shake by me-
chanical means for 30 min, and sonicate for 5 min. Dilute
with Diluent to volume, and centrifuge a portion of this solu-
tion. Quantitatively dilute a portion of the clear supernatant
to a concentration of 0.02-0.03 mg/mL of alendronic acid.
Sample solution: Transfer 5.0 ml of the Sample stock solu-
tion to a 50-mL polypropylene screw-cap centrifuge tube
containing 5 ml of Solution B, and mix for 3 min. Add 4 ml
of Solution C, and agitate for 30 s. Allow the solution to
stand at room temperature for 25 min. Add 25 mL of meth-
ylene chloride, and agitate for 40 s. Centrifuge the mixture
for 10 min. Use the clear upper aqueous layer.
Blank: Transfer 5 mL of Diluent to a 50-mL polypropylene
screw-cap centrifuge tube containing 5 ml of Solution B,
and mix for 3 min. Add 4 mL of Solution C, and agitate for
30 s. Allow the solution to stand at room temperature for
25 min. Add 25 mL of methylene chloride, and agitate for
40 s. Centrifuge the mixture for 10 min. Use the clear upper
aqueous layer.

youhana Hosny 1 m ago

✅ 1. Detector-related causes:
Lamp instability: UV or DAD detectors depend on a stable light source; an aging or unstable lamp will cause noise.
Detector cell contamination: Dirty flow cell → light scattering → increased noise.
Temperature fluctuations inside the detector (especially in refractive index detectors).
✅ 2. Mobile phase-related causes:
Impurities in solvents: Even high-purity solvents may contain UV-absorbing impurities.
Air bubbles: Entrained gases passing through the detector cause spikes or drifting noise.
Incomplete degassing of mobile phase.
✅ 3. System-related causes:
Pump pulsation: Mechanical inconsistencies cause pressure and flow fluctuations → noise.
Leaks or loose fittings → flow instability → noisy baseline.
Column issues: Damaged or contaminated columns may cause unstable baseline.

Sebästien Gonzälez O.o 23 d ago

C18 classical and friendly hahaahha

youhana Hosny 23 d ago

:D

youhana Hosny 1 m ago

check the system for air bubbles or leakage

Alan Cervantes 1 m ago

Bad purge between primary and accumulator plungers. or maybe a leak. check all tubing and connections

Sebästien Gonzälez O.o 23 d ago

bubbles on your system, because bad purgue o review bottle mobile phase