# Hach Method 10360 – Luminescence Measurement of Dissolved Oxygen (LDO ®

# ) in Water and Wastewater

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### Hach Method 10360 Luminescence Measurement of Dissolved Oxy g en in Water and Wastewater Revision 1.1 Januar y2006

1.0 Scope and Application

1.1 This meth od i s for the dete r minatio n of dissol ved oxyg en (DO) in su rface a nd g r o und water, an d munici pal an d indu strial waste w ater. 1.2 The metho d may be use d as a re pla c e m ent for the modified Wi n k ler a nd mem b ran e ele c tro de pro c ed ures fo r the mea s urement of DO in wa stew ater treatment proce s se s su ch as aeration a nd biologi cal nut rient ba sin s , effluent outfalls, re ceiving water, an d in Bioche mical Oxygen Dem and (BOD) dete r mination s wh ere it is de sired to perfo rm nonde stru cti v e DO mea s u r eme n ts. 1.3 The method is for use in the Environmental Protection Agency’ s (EPA’s) survey and monitoring prog ram s un der the Cl ean Water Act. 1.4 This meth od i s ca pabl e of measuri ng DO in the rang e of 0.20 to 20 mg/L. 1.5 For this m e th od, the Metho d Dete ction Li mit (MDL; 40 CFR 1 36, Ap pendix B) ha s been dete r mi ned as 0.05 mg/L and the Mini mum Level (ML; Referen c e 15.4) ha s b een set at 0.20 mg/L.



### 2.0 Summar y of Method

2.1 This lumi ne scence-b a sed sensor p r o c ed ure me as ure s the light emissi on charact e risti cs from a lumine scen ce -ba s ed rea c ti on that take s place at t he sensor-water i n terface. A light emitting diode (LED) provid es in cide nt light requi red to excite the luminoph ore su bstrate. In the pre s en ce of dissolved oxy gen the re acti on is supp re ssed. The resulting dynami c lifetime of the excited luminop hore is evaluate d a nd equ ated to DO co ncentration.



### 3.0 Interferences

3.1 There are n o kno w n inte rfe r en ce s at normal wa stewater co ncentrations that interf ere with DO detectio n and quantificatio n usin g this method.



### 4.0 Safet y

4.1 This meth od doe s not add ress all safety issue s asso ci ated with its u s e. The labo ratory is respon sibl e for maintai n in g a safe work envir onm ent and a currentawarene ss file of OSHA regul ation s re gardi ng the safe handli ng of any chemi c al s sp ecifie d in this metho d . A referen c e file of material sa fety data she e ts (MS D Ss) sho u ld be av ailable to all p e rsonn el invo lved in these analyses. Additional information on lab o rato ry safety can be fou n d in Refere nce s 15.5-15.6.



### 5.0 Equipmen t

Note : Brand na m e s, su ppliers, and part numbers are for i llustrative pur poses only. No end orsement is im plied. Equivalent perfor m ance m a y be achieved using apparatus an d m a te rials other than those s pecified here, but d e m onstr ation of equivalent perfor m ance th at m eet s the require m e n t s of th is m e thod is the responsibility of the laborato r y.

5.1 Lumine s cent dissolved oxy gen mete r an d sen s o r(Ha c h Compa n y LDO ® , Hydrolab LDO ® , or equivalent ). 5.1 BOD bottle 3 00-m L 5.2 Magneti c Stirring plate (opt ional) 5.3 Magneti c stirring device (o ptional)



### 6.0 Standards

6.1 Initial Calibration – add a p p r oximately 1⁄4 inch of re age nt water to a clea n BOD b o ttle and stop per.

6.1.1 Shake vigo ro usly for ~ 3 0 se con d s. 6.1.2 Allow 30 minutes for the B O D bottle and its contents to equilibrate to room tem perature.

1Ha ch Metho d 10360 – L u m i nesce nce Measure m ent o f Dissolved O xygen in Wat e r and Wa ste w ater

6.1.3 The sto ppe r may now be removed from the BOD bottl e and the pro be inserted fo r calib ratio n purp o ses.

6.2 Calib ration V e rificatio n , Initial Preci s ion and Recovery, and On-goi ng Pre c isi on and Recovery, - Add app roxi mately 1500 mL of orga nic-free water to a 2-L bea ke r.

6.2.1 Allow the wat e r to equilib rate to room temperature ( ± 2 o C). 6.2.2 Usi ng a ste a d ystream of ai r ( ≈ 1 0 – 40 mL per min u te) ae rate the water fo r a mi nimum of 30 minutes. 6.2.3 At the comple tion of aeratio n, let wa ter re -equili brate to room tempe r ature ( ± 2 o C) for 30 minutes a nd note the baro m etric p r e s su re of the labo ratory du ring prep aration. 6.2.4 Tran sfe rthe aerate d wate r to a BOD bottle until overflowin g and stoppe r. 6.2.5 Cal c ulate the theoreti c al di ssolved oxyg en co ncentrat i on usi ng a di ssolved oxyg en table such as Hit c hma n (197 8).

6.3 Method Dete ction Limit – Prepa ring di ssolved oxyg e n referen c e water at co nce n tration s othe r than air-satu rated water req u ire s sp eci a lized equipm ent an d expertise n o t generally available to ro utine analysi s labo ratorie s . It is recom m en ded that these sa mples b e obt ained throug h a comme rcia l

sou r c e

.

6.3.1 Usi ng a NISTtracea ble so urce of oxygen and nitro g e n , saturate re agent water to a desi r abl e DO con c entration. 6.3.2 Colle ct the prepared water in 300-mL BOD bottle s an d stopp er.



### 7.0 Sample Collection P r eservation and Storage

7.1 See Title 40 of the Code o f Federal Reg u lation s Part 136.3, Table I I (Section 15. 3) for info rma t ion rega rdi ng re q u ired sam p le colle ction con t ainers, pre s e rvation tech ni que s and h o l d ing times,



### 8.0 Quality Control

8.1 It is recom m e nded that ea ch laboratory that us e s this method be re quire d to ope rate a form al quality assurance pro g ra m (Refe r en ce 15.1). The mi nimum req u irem ents of this prog ram consi s t of an initial dem onstration of laboratory cap ability and on going a nalyses of labo rato ry prep are d water stand ard s a s a test of conti nued p e rfo r m ance to asse ss a c cu racy a nd pre c i s ion. Laboratory perfo rman ce i s co mpa r ed t o establi s h e d performan ce criteri a to determin e if the result s of anal yses meet the perf o rma n ce ch arac teri stics of the method.

8.1.1 The analy s t shall make an initial demon strati on of the ability to generate a c cepta b le accu ra cy and preci s io n with this met hod. This a b il ity is established a s de scri bed in Sectio n 8.2.

8.1.2 The labo rato ry shall, on an ongoin g ba si s, demon strate throug h cali bration ve rification and analysi s of the ongoi ng pre c isi on an d re covery samp l e that the ana lysis sy stem i s in co ntrol. These proced ure s are de scribed in Se ct i ons 8.3 a nd 8

. 4, resp ective ly. 8.1.3 Acco mpa n yin g QC for the determi nation of DO is re q u ired p e r a nal ytical batch. An analytical batch i s a setof sample s p r ocesse d du ri ng a co ntiguo us 8-hou r pe riod. Each an alytical batch mu st b e accomp ani ed by a calib ration verificati on and o ngoi ng pre c i s ion and re cove ry sampl e , re sul t ing in a minimum of three analyse s (1 CV, 1 sampl e , and 1 OPR).

8.2 Initial demonstration oflaboratory capability.

8.2.1 Method Dete ction Limit (M DL) – T he M D L an d ML for DO i s not a requi rem ent in Method 1036 0. However, its dem onstration is recom m en ded as a pa rt of the labo rato ry’s overall Q C prog ram. 8.2.2 An achieve d MDL an d ML less than or e qual to the MDL an d ML in Table 2 is re comm end ed prio r to the practice of this method. The ML is esta blishe d by multiplying the MDL by 3.18 and ro undi ng to the numbe r nea re st to (1, 2, or 5) x 10 n , where n is a positive or negative integer.

2Ha ch Metho d 10360 – L u m i nesce nce Measure m ent o f Dissolved O xygen in Wat e r and Wa ste w ater

8.2.3 Initial preci s io n and re cove ry (IPR) - To e s tabli s h the a b ility to generate accepta b l e pre c isi on and a c cura cy , the analyst shall p e rfo r m the followin g operation s :

8.2.3.1 Prepa re an d measure f our sample s of the IPR stand ar d (Se c tion 6.2) acco rdi n g to the pro c ed ure begin n ing i n Section 10. 8.2.3.2 Usi ng the re sults of t he setof four analyse s , com put e the average percent recovery (X) and the st anda rd deviat i on of the percent re cove ry(s) fo r DO. Use the follo wi ng equatio n for calcul ation of the stan dard d e viation of the percent recovery:



# ( )

1 2

2

−

−

= 

# ∑ ∑

n n x x

s

whe r e:

n

=

N u mb er of s a mp le s x = Con c entration in ea ch sam p le

8.2.3.3 Comp are s a nd X with the corre s p ondin g limits for initial pre c isi on a nd re cove ry in Table 1. If s and X meet the accepta n ce cr iteri a , syst em perfo rma n ce i s acce ptable and analysi s of samples m a y begin. If, h o weve r, s exceeds the precision limit or X falls outsi de the ran ge for recove ry, syst em perfo rma n ce i s una cce p table. In this event corre c t the probl em, and re peat th e test.

8.3 Calib ration ve rification – D O calibration is perfo rmed im mediately pri o r to sam p le analysi s

.

8.3.1 Prepa re a cal i bration ve rification stand a r d (Se c tion 6. 2) with ea ch analytical b a tch. Analyze according to the pro c e d u r e beginni ng in Secti on 10 a n d comp are the recovery re sults to those in Ta bl e 3. Actual average re cov e ry and sta n d a rd deviatio n sho u ld be within the spe c ification s in Table 1.

8.4 Ongoi ng calib ration an d preci s ion a nd recove ry - To demon strate that the analy s is system i s in control, and a c ceptabl e pre c isi on an d accuracy is b e in g maintaine d with ea ch an alytical batch, the analyst shall perfo rm the followin g ope rations:

8.4.1 Prepa re a p r e c isi on an d re covery stand ard (S e c tion 6.2) with ea ch analytical b a tch a c cordi n g to the pro c ed ure be ginni ng in Section 10

. 8.4.2 At the end of each analytical batch of sa mp les, an alyze a pre c isi on and re cove ry stand ard and compa r e the con c e n tra t ion recovery with the limits for ongoin g p r eci s io n and recove ry in Table 1. If the recove ry is i n the rang e spec ifie d, mea s ureme n t pro c e ss i s in co n t rol and analysi s of samples m a y proceed. If, however, the recovery is no t in the specified range, the analytical p r o c e ss i s not in control. In this event, co rre ct the pro b le m, recali brate and verify the calib ratio n and re analy z e an alytical batch, repeati ng the ong oin g pre c isi on a nd re cove ry tes t. 8.4.3 The labo rato ry should a dd results that p a ss the sp ecif ication in Ta b l e 1 to IPR and previou s OPR data an d update Q C cha r ts to form a gr aphi c rep r esentation ofcontinu ed la borato r y perfo rman ce. The labo rato ry shoul d also devel op a statement of laborato r y data quality for each analyte by calculating t he average percent recovery (R ) and th e stand ard d e v iation of the percent recove ry (sr). Expres s the a c cura cy as a recovery interval from R 2sr to R + 2 s r. For exampl e, if R = 95% an d sr = 5%, the accuracy is 85% to 105%

.

8.5 Dep endin g u pon spe c ific p r og ram requi rements, field repli c ate s ma y be requi red to assess the pre c isi on an d accura cy of the sam p ling and sample transportin g techni que s.

3Ha ch Metho d 10360 – L u m i nesce nce Measure m ent o f Dissolved O xygen in Wat e r and Wa ste w ater



### 9.0 Calibration and Standardization

9.1 Becau s e of th e possibl e diversity of future LDO in stru ment hardwar e, no detailed operatin g

con d ition s are provide d . The analy s t is advise d to follow the re co m m ende d ope rating co nditio n s provide d by the manufa c tu rer. It is the resp on sib ility of the analystto verify that the instru men t config uratio n and op eratin g conditio n s sa tisfy the analytical req u irem ents of this m e thod an d to maintain qu al ity control dat a verifying instrum ent pe rfo r man c e a nd a nalytical re sul t s. 9.2 Wate r-satu rat ed air (Se c tio n 6.1) is us ed for ins t rument c a libration. 9.3 Calib ration ve rification (Section 8.3) is pe rforme d with air-s a turated water prior to any DO sample measurement s to the meth od sp ecifi c ati ons.



### 10.0 Procedure

10.1 Instrum ent Setup and Sa mple Analysi s – follow the instru ment m anufa c ture r’ s instru ction s for instru ment se tup and samp le analysi s

.



### 11.0 Data Analysis and Calculations

11.1 Follow in stru ment manufa c ture r’ s instru ction s

.


### 12.0 Method Performance Acceptanc e Criterio n Section Limit

Method Dete ction Limit 8.2.2 0.05 mg/L

Minimum Lev el 8.2.2 0.20 mg/L

Initial Accu ra cy 8.2.3 95% to 105% Initial Preci s i o n 8.2.3 2.1%

Ongoi ng Accura cy 8.2.3 95% to 105% Ongoi ng Pre c ision 8.2.3 2.1%



### 13.0 Pollution Prevention

13.1 There are n o stand ard s o rreag ents u s e d in th is meth od that pose any threat to the enviro n me nt.



### 14.0 Waste Management

14.1 It is the laboratory’s respo n sibility to co mply wi th all federal, state, and lo cal re g u lation s gove r ning

wa ste mana g e ment, parti cularly the ha zardo u s wa ste identification rule s and la n d disp osal rest rictio ns, a nd to prote c t air, wate r, an d land by min i mizing a nd control all rele ase s from fu me hood s an d be nch o peration s . Complia nce with a ll se wage di scharg e permit s and regulatio ns i s also requi red. 14.2 For furth e r inf o rmatio n on wa ste mana g e m ent, con s u l t “The Wa ste Manage mentmanual for Labo rato ry Personn el”, an d Less is Bett er: Labo ratory Chemical M anag ement fo r Wa ste Red u ctio n”, b o th available from the Ame r ica n Soci ety’s De partm entof Governme nt relation s a nd Scien c e Poli cy, 1155 16 th Street N.W., Wa shin gton, D.C. 200 36.



### 15.0 References

15.1 Handbook of Analytical Qua lity Control i n Water and Wastewat er Laboratori e s,” USEPA, EMSL-CI, Cinc innati, OH 45268, EPA-600 -4-79-019, Marc h 1979. 15.2 Hitchm en, M.L. (1978 ) Che m ical analysi s . Vol. 49. Measu r em ent of Dissol ve d Oxyge n . Wiley and

son s , Ne w York. 15.3 Title 40, Cod e of Federal Reg u lation s (40 CF R), Part 136. 15.4 Protocol for EPA Approval of New Methods for Organic and Inorganic Anal ytes i n Wastewater and Drin kin g Wat e r @ (EPA-821-B-98-003, March 1999).

4Ha ch Metho d 10360 – L u m i nesce nce Measure m ent o f Dissolved O xygen in Wat e r and Wa ste w ater

15.5 “OSHA Safet yand Health Standards, G eneral I ndu stry,” (29 CF R 1 910), O c cupa tional Safety and Health Admi n i stration, OS HA 2206 (Re v ised, Ja nua ry 1976) 15.6 “Safety in Academi c Ch e m istry Lab ora t ories, ” Ameri c an Chemi c al Society, Co mmittee on Chemical Safety, 3 rd Edition, 1979.



### 16.0 Tables

16.1 Acce ptan ce Crite r ia for P e rform a n c e tests – T he Q C perfo rma n ce crite r ia for t h is metho d was perfo rmed with a Ha ch Co mpany HQ 10 LDO ® meter usin g the am bient use se n s or m ode (se e Ha ch Compa n y Instrume nt Manual ). Ca libra tion wa s perfo rmed with water-saturated air.

Table 1. Initial Precision and Re cov e ry Method Performan ce IPR Rang e IPR DO Co n c

. (mg/L) 97.5 % Lo w e rLimit of Re cov e r y ( % ) 97.5 %UpperLimit of Re cov e r y ( % ) 95 % Upper L i mit of Precision ( % ) Low 1.72 – 1.74 95.0 104.0 2.07 High 7.22 – 9.23 95.8 104.8 1.26

Table 2. Method De tec t io n and Minimum Limit Performanc e MDL Tes t DO Conc entra t ion MDL ML 0.07 mg/L – 0

. 09 mg/L 0.05 0.20

Table 3. Calibration Verification Perfo r mance

CV DO Conc entra t ion Av erage % Recov e r y %Standard Dev i ation %Relati v e S t andard Dev i ation 7.22 mg/L – 9

. 23 mg/L 100.1 2.5 2.5



### 17.0 Glossar yof Definitions and Purposes

The definition s and p u rp oses are sp ecifi ed to this met hod but have been confo r m ed to comm o n

usa ge a s mu ch a s po ssi bl e.

17.1 Units of weig ht and mea s u r e and thei r a bbreviatio n s

17.1.1 Symbols

o C degree s Cel s i u s 17.1.2 Alphabeti c al cha r a c ters mg/L milligram per liter

17.2 Definition s, a c ro nyms, an d abbreviatio n s

17.2.1 LDO ® - Luminesce nce dissolved oxyge n 17.2.2 BOD: Biological oxygen d e mand 17.2.3 DO: Dissolve d oxygen 17.2.4 CV: Calibration verific a tion 17.2.5 MDL: Method detection limi t 17.2.6 ML: Minimum level 17.2.7 IPR: Initial preci s ion a nd recove ry 17.2.8 OPR: On-goi ng pre c i s ion and re cove ry

5Ha ch Metho d 10360 – L u m i nesce nce Measure m ent o f Dissolved O xygen in Wat e r and Wa ste w ater



### Appendix

6